It looks to be heading to Louisiana, but Florida is getting the bulk of the rain. As far as storms go, this should be pretty mild, but you never know what tornadoes might pop up. Driving could be tough. Trees can fall on power lines.
Hopefully, those of us in the storm zone just get some soaking rains and our solar power will keep the lights on and set an example for our neighbors to follow.
Ok, you know I like to talk about safety, often based on experience, so here is a quick one I bet you haven’t thought about.
I am planning to try some of those 10 cent FS70 solar panels that Sun Electronics is selling and then write a review. I have actually used 4 of them in the lighting system in my “boxcar”, a 40′ boxcar-red shipping container. At the Solar Shed, some space freed up in my test rack, so I reconfigured for these modules. Next step was to fetch them and try them on a larger scale.
They are not big, but they are heavy, so I move them only two at a time. With one pair on board the Solar Yamaha, I went back for another. I am very careful with these as the panels can put out about 100 volts and some are missing the MC3 connectors, exposing bare wire.
So I curl my fingers around the corner to tip it toward me–there should be no wires at the corner–and, OMG!!!! 100 volts, my hairy hind end! It was more like 10,000 volts! I fully expected to see a charred nub where the finger used to be, but, no, there it was, all pink and healthy-looking, even if it did still feel like it had a hot nail driven through it. What the heck?
Then I saw the wasp fly out from behind it! Great! One more thing to worry about. If there is a moral to this story, it would be to watch out for Mother Nature. She is a practitioner of Murphy’s Law. Look out for wasps behind panels that have been leaning. Black widow spiders like to live under things on the ground. Don’t overlook the possibility of a snake or a scorpion under a pallet. It’s always something, isn’t it?
For a day or two, I went around with a hand that looked like those big foam “we’re number one” hands that people wear at football games. I learned a lesson I won’t forget and I am admitting to it so maybe you won’t have to learn it for yourself.–Neal
In it was a handout touting the cooperative’s dedication to service to its members. The coop power had been out for over 3 hours at that time, owing to a car vs. pole incident. A neighbor had power because I could hear the generator buzzing. I had power, too, but nobody could hear it.
Back to the power bill. I have been waiting for it with glee. How often to you hear of that? Pretty often when you are dealing with people who enhance with solar.
This was the culmination of efforts on one of my latest solar experiments. I have done a writeup on the whole deal, but I just thought I’d show the power bill first. $50. There was a time when I would have thought that was terrible. $9 of it was for electricity and the rest of it was….terrible. Fortunately I “don’t have” grid intertie, or they’d tack on another $50 service fee.
What I have done is put the “generator circuit” and a/c completely on solar. That left the big stuff. I added a limiting grid-tie apparatus that helped during the day, but it wasted a lot of power fighting for the solar. The latest revision is battery enhanced grid-tie. It works all day, all night and the two units never fight. This is what happened to the bill.
The reason any use showed up at all is that the oven and the clothes dryer each run at about 5kw and the little grid tie units I use are only good up to 1900 watts with the sun shining and a bit less at night. Several blackberry cobblers were baked last month, running up the power consumption, but well worth the expense of about 13 cents each. I’ll release the full story on this project in a day or so.–Neal
Last week, during my morning coffee and internet infusion, I read of a very large solar power plant being planned for Bureau of Land Management (BLM) land in Nevada. Then, this morning, I read about a 6.5 earthquake in Nevada. Man, it’s always something going wrong, isn’t it? Then I heard Puerto Rico had one!
It just goes to show that normal, everyday conditions are not the only ones to plan for. Here in Florida, we don’t get a lot of earthquakes. I recall a rattle or two, but nothing like the 1781 quake of 6.5 recalled by Chaplain Waldeck of the German mercenaries who were defending Pensacola from the Spanish at the time. That was enough to crumble chimneys and knock barracks houses off their foundations.
I wonder if there are special design considerations for solar in earthquake zones. Years ago, when I was providing management systems for distribution warehouses around the country, I notice that most had steel beams. However, in earthquake zones in California, Washington state and Alaska, the beams were wooden, because they would flex.
Most solar installations I have seen use galvanized steel posts or beams. Put a heavy mass of panels on top of that and the mass will try to stay fairly still while the poles take the shock and perhaps bend. I’m thinking there needs to be something springy or slidey involved in the mounting. I think I will look into seismic mounting to satisfy my curiosity.
Here on the Gulf Coast and up the East Coast, we have hurricanes. Forecasters were talking this week about a storm already forming and there was a weak swirling mass that went through Miami and is now crawling up the Atlantic coast as a tropical storm. Call those a warning. It is time to prepare NOW.
We have a long history of hurricanes here in Pensacola. Juan Tristan de Luna y Arellano and friends sailed into the bay in 1559 to set up a colony. A few weeks later they were holding onto trees for dear life while their ships were being bashed to bits in the shallows. Bienvenidos a Florida, amigos!
Despite this long history with hurricanes, people tend to forget the lessons. It has been maybe 15 years since we’ve had a good one, here, but we have had some whoppers on either side of us. Trees grow up along the powerlines and even a mild storm can knock the grid down for a while. Trees are tough on a roof, too. When hurricanes Erin and Opal came through, the stronger one did not cause as much damage as the first because the trees had already been taken out. The last big storm that came through was so strong it didn’t need any help from trees because the power poles blew over. When Hurricane Michael came through just east of us, it blew pretty much EVERYTHING over.
A battery backup system can help keep the lights on during and after a storm. The 2500 watt system I had back during the storms helped keep life fairly normal in the 5 weeks before the power company made it to our street. A daily top up of the batteries with the generator kept things going without the noisy generator running 24/7. NOW is the time to act if you are considering backup. John’s guys already have some package plans, so it isn’t a big deal to get moving on this. My house was wired for this from the beginning, but any good electrician can retrofit this stuff, if you can’t do it yourself.
And what if you have solar power, already? Is it grid-tie-only or can it provide backup after the storm? A LOT of people who start out with grid-tie regret that decision when the grid goes down. There is equipment that will let you have it both ways! Maybe what you already have has an option you are not using. Check into it!
What about your precious solar array, assuming you have one? The Rocky Mountain Institute has a free report on what has been known to fail and what holds up against a storm. Find it. Read it. Essentially, use strong racks and use bolts instead of sheet metal screws.
In my own case, I know I have vulnerabilities. The solar shingles that Sun Electronics gave away are only rated for 60 mph. That worries me. That can be improved upon, but is way too much work. Additionally, I have a number of other modules on temporary racks. Steel stakes driven into the ground help anchor the wooden racks, but the panels are held on with screws. All of these panels I plan to remove and store in a safe place until after a storm blows over. Assuming Sun King, the solar boat, survives in its shed, it can come out and connected with the stored panels provide thousands of watts of solar input and its 5kw inverter can keep necessities running in the house. That’s the plan, anyway.
What else can you do to plan? Have some water stored for drinking and maybe a plastic garbage can full to use to refill the toilet. Kitty litter and a 5 gallon bucket can serve as a toilet if there are unpowered lift stations involved. There are ceramic water filters, like the Berkey, that can clean up pretty much any water source or you can make a purifier with a ceramic filter kit from ebay and a couple of plastic buckets.
You need access to food. The virus situation has shown us how vulnerable we are there. Normally Walmart sells a 2 or three day meal package in the camping department. Sam’s Club will deliver a one year supply for the whole family, but right now you have to get in line. There are many options for camp stoves, including those that do not require commercial fuel, but if you have backup power, a microwave and a coffee pot you can prepare all sorts of meals. Yes, you can make pancakes in a microwave, if you know the trick! A single “burner” induction plate would be a good tool in your emergency kit. (My bro was camping at my place last week and used one plugged into an inverter to make breakfast.) Commercial MREs don’t last as long as the military stuff. I have cases of GI MREs dated 1984 that I would still eat in a pinch. Under normal circumstances, you could buy a big sack of beans and another of rice and be fine for a while. Cheap, easy foods seem to be in short supply, these days, but they can be found and it is best to set aside a bit for a stormy day.
You can’t prepare after a storm and supply chains are already strained with the pandemic, so get busy!–Neal
I read online solar news journals every morning while the coffee soaks in. Most of it is grid stuff, but those guys are in it for the money and have the bucks to pay for the research, so I pay attention.
I also paid attention when I lived very closely with my solar power during my 44 days aboard Sun King. What I learned there was that we waste an awful lot of solar potential. I had 1620 watts of panels, which is not a lot when you consider that it provided motive power, lighting, cooking and, most importantly, coffee. However, sitting there all day, arm’s length from the meters, I could see that by 10 or 11 a.m., the batteries were usually topped up and less than half of the solar power was being used to run the motor. The rest went unused.
I mitigated this, somewhat, by changing my load/use strategy. After about the first week, I’d get underway about 5 a.m. to burn off some of the 350 a.h. battery storage I had. That got me further up the river each day, typically around 50 miles and up to 100 miles, and I got to use more of those kilowatts shining down.
At home, I see much the same thing. By the time I get up and out, around noon, the batteries are often topped up or at least in bulk charge. The air conditioning season is beginning to make a seasonal adjustment to the load pattern. The house a/c starts up around 0930 and the man cave a/c in the Solar Shed starts around 10. I encourage my wife to use heavy loads, like the dishwasher (1kw) and cooking (separate solar hybrid, there) during the sunny hours. She baked me a blackberry cobbler this morning! She’s ok.
I honestly don’t know how many kilowatts of solar I have available right now, but I do know that I am not using all of it on a sunny day. I also know that when it is cloudy, I don’t have enough.
So back to the grid guys, that’s where the big money is and they keep coming up with bigger batteries and cool new gear. One battery beginning construction is rated at 100mw for utility backup. That is not mwh, that is mw output. Furthermore, it is rated to run for 150 hours at full output. 6 days at 100 MILLION watts! If you know the math, try calculating the number of John’s Sun 230 batteries you’d need to match that. Furthermore, the new chemistry of that battery uses water and air! Tesla has provided some pretty sporty lithium grid batteries in Australia, too.
All of this work is leading up to solar providing more power this year than coal. They can do this because they’ve been building an awful lot of solar AND they have been figuring out how to not waste it and continue using it after the sun goes down.
A new study from Wartsila (I’m sorry, but that name just conjures up an image of the offspring of Godzilla and a warthog) suggests the ultimate setup for the grid is to install 4.3 times the peak load of solar in sunny areas, with 4 to 10 days of storage. That may sound a bit extreme, but a utility can’t compel you to do your heavy power use only during the day, or even to be conservative in your consumption.
In looking at my own system, I have always tried for 4 days backup, though my ever-increasing load makes it closer to a single day if I maintained all loads and the sun didn’t come up. I’ve nearly 800 a.h., now and plan to add another 440 a.h. soon. That’ll give me nearly 60kwh of battery, but, of course, that’s only 30kwh at the usual 50% drawdown limit. I’m sure that won’t satisfy me, either, nor will it meet the Wartsila guidelines.
As far as meeting their guidelines on solar input, my inverter was tripping above 5500, so let’s say my current peak is 6kw. By their formula I should have 26 kw of solar input! Yikes! You guys will have John’s crew really hopping if you all install 26kw of panels! Or more. My best guess is that I have around 13kw actually running. I know I have two strings of around 720 watts each that are not working and maybe that much more up, but not connected pending the construction of the final bay of the Solar Shed. Just sitting in piles I have another 5 or 6 kw of panels that I have not nailed up, yet, but it seems I can get pretty close to their goal when the project is finished. My shortfall can be mitigated by not running street lights and traffic signals all night.
So that leaves batteries. Someday we should see all of this utility battery development trickle down to the solar homeowners. It is already, really, with the drop in lithium prices. At the present time, what I see is the cheapest entry into storage is the Sun Electronics Sun 230. Best bang for the buck, if you have the upfront cash, seems to be the SimpliPhi lithium. They are pricey, but should outlast you. Ask Roberto about them.
How does your system stack up to these new guidelines?
I told you the other day I had reached the limits of what my homebrew 5500 watt inverter could do. I had a 10kw driver module to install, but it was bigger and was going to need some more cables.
One night I switched the house to grid, ran a power cord from the Sun King for lights and I shut down the inverter for a recon. What I found was that I could use what was in there, but I need to add some cables because a 10kw inverter eats lots more amps than a 5kw unit. I made measurements and notes and buttoned things back up a threw all the switches. Next day I built cables.
John likes me to talk about the basics, so here was a perfect opportunity. If I were building this inverter from scratch, I would use four parallel #6 cables because they would add up to plenty of current and wire that is easy to bend.
I promise we’ll eventually get to the fun stuff, but we gotta do the book learnin’ stuff first.
Let’s start with the cable itself. I’m talking power cables here, for high current. These are cables you might use to join batteries or to go from batteries to inverters. How big do you need? Well, I want to run a 10kw inverter on 48 volts, so it is easy to find out how many amps. 10,000/48= a bit over 200 amps. NOW the question is what size cable do I need?
Look on the internet and you can find ampacity for various gauges of copper wire. I don’t like most of these charts because they relate more to how many amps you can get through the wire without melting the insulation or starting a fire than how much is safe, practical and has little resistance. I have a memory trick I use to come up with numbers I like. I can remember the common household gauges of 12 and 14. You use 12 on 20 amp circuits and 14 on 15 amp circuits in the house, though 14 gauge is banned in some places.
Wires and cables are typically even numbered and if you go down two even steps, you double the capacity. So going from 14 to 10 you double from 15 to 30 amps and from 10 ga. to 6 ga. you double it again to 60 amps. Some charts will say 6ga. will carry a lot more and it will, but it will get hot and drop some volts. If I were making a long cable, I would run less than 60 amps in 6 ga. cable. It boils down to USE A BIG ENOUGH CABLE. Or enough little ones.
But wait! Why am I building 60 amp cables when I need 200 amps? If I went with 4 60 amp cables, filling up all the terminals, I’d be good for 240 amps. No problem.
I’m not going to make it that easy, because the negative line already has a good 2 gauge cable. That’s two steps down from #6, so we double again. That’s a 120 amp cable. Adding my two 60s and we have plenty of amps.
Regardless of whether any of that sank in, we are going to build 6 gauge cables today, because that’s what I need for my project. My favorite cable for this is marine cable. It is fairly tough, very finely stranded and flexible and every strand is tinned. In some cases you might be required to use cable that is UL listed for solar applications. If you are wiring inside your inverter or making cables for your golf car batteries, then use what works for you.
What do we need? Wires, terminals and tools. I have a roll each of black and red #6 cable I’d bought for something else. Having both black and red makes it pretty obvious which is for positive and negative. Here’s a tip, bolt cutters make great cutters if you have a set just for cables. You won’t be happy if you cut the bolt first.
The inverter module came with some terminals that have foldover tabs. They are not my favorite, but they were free and they fit the screws. I also have some heavy duty tinned terminals, too. Terminals, by the way, are sold according to wire size and stud size. Putting #6 wire in a terminal made for 00 gauge wire is not a good plan. Match your terminals to your cables. It’ll mean having more terminals in the bin, but will make for better work.
You’ll need some pliers to bend over the tabs on the copper terminals, but don’t think that makes you done.
You need a crimper tool. Some look like bolt cutters, except they crimp instead of cut. I have a couple that are like little presses that hold the terminal in place while you give it a couple of whacks with a big hammer.
The tool I use works best when it is sitting on an anvil. My shed anvil has gone missing. There’s one over near the barn, but that’s a long way and it is heavy. Today, we are substituting the stump of an oak tree that dared to extend a limb over my solar array. Take that!
An anvil works better. Last time I lost an anvil I found it with a bush hog. That wasn’t good.
Back to tools, you’ll need a sharp knife. Keep it simple. I use a sodbuster and a lot of electricians use Barlows. A butane mini torch is very helpful for soldering. You’ll need a roll of solder, too. I like old fashion 60/40 rosin core. Never, never ever use acid core or stuff from the plumbing department. A good collection of shrink tubing is very nice to have for professional results.
Here we go, now. Determine how far back you need to strip off the insulation. Use the knife to go around gently, getting through the insulation without cutting the wire strands. For the open terminals, take pliers and bend over the tabs the best you can to hold it in place. On the tube terminal, just slip the cable in, making sure you get all the strands in.
Next, put your wire and terminal in the crimper and do the deed. In the kind I use, a “+” sign is embossed to show you got a good crimp. Some people are happy to stop here, but we are going to solder, too.
To solder, you’ll need your mini torch. A jet lighter will work on these smaller cables, too. Put the flame on the terminal, with the overshoot going away from the insulation.
On an open terminal, like our copper example, poke at the cable to see if it is ready to melt solder. Don’t put the solder in the flame. It will melt and fall into your shoes. On the closed tube terminal, poke the solder in at the gap between the insulation and the metal. When it begins to melt, run it on in. When it begins to puddle you have enough. A slight shake will get rid of excess. Let the cable cool before the next step. Warning: If you are making really big cables like 00 and 4/0 gauge, it WILL get hot.
Shrink tube comes in all sizes and types. There is some really thin cheap stuff on ebay and you should avoid it. The best and most expensive is usually referred to as marine type. It has a melty inner lining that seals up both ends. This is great on boats and around battery acid.
I like to keep red and black tubing to help denote polarity. Sometimes I only have black cable and the colored ends help keep things straight. Ideally, you own a heat gun to shrink the tubing. A hair dryer can work in a pinch. If you are careful, the mini torch works, too. Just back off 3 or 4 inches and keep the flame moving. You can screw it up in an instant.
One other handy trick is to buy CLEAR shrink tube. You type/print a message on paper, like “Main Inverter Cable, Positive”, slip the clear tubing over the cable and slip the message under the tubing. When shrunk, you have a permanent ID for that cable.
So there we have ’em, the new cables to go into the inverter project. I will eventually double up the 2/0 cable going from battery to inverter. The ones that are there are adequate, but I will have less resistance and voltage drop. Why double cable instead of bigger? First, I don’t do 4/0 cable. I can get it for the same price as 2/0, but I just don’t like it. Second, I have the 2/0 cable and maintain a supply of terminals.
In case you are wondering how the inverter project turned out, it went splendidly.
It fired right up without any complaints. I still have a few loose ends on changes to fans and control cables, but it is running and we’ve had no more overloads.
John tells of the glories of swimming with the fish in Miami’s bays. Then he tacks on something solar. It’ll be a while before I get back into the water, but I have some solar sea stories.
I built an electric boat and it was great, but I couldn’t travel with it. I could easily do a 20 mile day trip, but I wanted to go places and explore. That is how Sun King came about.
It was a 16′ Luger Leeward hull stretched to 20′ to give it a more efficient stern. After much experimentation, I installed a single 80lb thrust motor, based on a Minn Kota troller. I outfitted it to do sidescan sonar bottom surveys of our local river. I’m a historian, among other things, and there’s a certain amount of history down there. It is a great boat for exploring rivers.
Did I mention that the electric motor got its power from 6 270 watt “B” panels? So there you go, a solar boat. Infinite range.
The first time I tried my river boat in a bay was nearly the end of me. It sits very low in the water and sometimes bay water does not sit low. Don’t even get me started on the Gulf of Mexico! Eventually I got things sorted and learned to deal with the limitations and I took some trips. Then I got this wild idea.
Have you heard of the Great Loop? Look it up. I know with Sun King’s limitations that trip is a nonstarter. However, there is what I call the Mississippi Loop or the Short Circuit. Essentially, the state of Mississippi, along with bits of Alabama, Tennessee and maybe some others, is an island!
You don’t believe that, do you? An island is, by definition, a parcel of land you can drive a boat around. You can drive one around Mississippi. I’ve done it.
I got in my river and went down to Pensacola, where I turned right and proceeded westward. I turned right again at Mobile and went up the Tombigbee River, which took me on up to Paducah, Kentucky.
The sun didn’t shine every day and on one stretch it went a good 4 days of cloud. I reckon I nailed the balance of solar power (1620 watts), battery capacity (350 ah) and motor load (625 watts at cruise). I did not go fast, but I went steady, often making 50 miles and maxing at 100 miles.
At Paducah, I turned to port (left) and went down the Ohio River to Illinois, where I turned left into the Mississippi. Yeesh. I was not prepared for the next thousand miles, but I survived.
Most boaters doing the Great Loop go south the way I come up. They don’t go down the Mississippi because there are only two places they can buy fuel, at Memphis and Greenville, before they make it to New Orleans. A solar boat doesn’t need fuel. I was doing something with my dinky 20′ solar boat that most boaters cannot do!
So here I am on the outskirts of New Orleans, docked behind the High Tide Bar and Grill and Marina and Convenience Store. I skirted the 12,000 hp pushboats, a hurricane and a tornado, but could I do the Gulf of Mexico? With this boat you want smooth water. Barring that, you want a wind on the stern and the boat will act like a surf board. Weather was lining up to go my way. It was going to be a matter of timing. I sought out local wisdom. I also sought flush toilets and real food. Noodle cups, MREs and Vienna Sausages are sometimes not enough.
I dined on Cajun seafood and monitored a discussion moderated by a young lady on where men could go in New Orleans for certain favors from ladies. She had everyone’s attention until she let slip that the aforementioned ladies were not actual ladies. Her audience pretty much lost interest after that and I looked at her more closely for signs of discrepancies.
I engaged in chitchat for a while with the guy next to me before being introduced to Rain Webb, the artist-in-residence. You didn’t know that a Bar and Grill and Marina and Convenience store had such, but this is New Orleans, mind you. Before he moved on he informed me that I was to meet with him aboard his sailboat later that evening. Oooookay. I don’t believe I have ever had such an evening of discussions on such a broad range of subjects. I really enjoyed it.
The next morning, Rain brought me a sack of avocados and oranges, to improve my diet on the final days of my voyage. He gave me a benediction, of sorts, informing me he was sending angels with me to protect me on my voyage. I thought that a bit odd, but this was New Orleans.
We checked with the cook, a former shrimper, who thought conditions would be good. Rain got in his kayak to guide me on a tour of the nearby fort and then guide me to Lake Catherine, where we parted company.
It was a short trip to the Pearl River, where I holed up waiting for the wind to align. The shrimper I met in a lock had called the waters ahead, “The Chopper.” I didn’t want to get chopped.
Finally, it was time to get underway. The wind was just right for the course I needed to sail, but I had to get around a point and had to tack back and forth to keep the boat dry-ish. Once around the point I was set. The seas were not dangerous, but they were not pleasant, either. After a while I realized that I was going to be out of luck if I wanted a cup of coffee or a hot meal. The galley was forward and I could not let go of the boat for a second. Fortunately, my custom was to rack up bottles of water and tea before getting underway, plus I had MREs behind the seat and Rain’s sack of fruit. I did fine, except for lack of coffee.
In the tedium of it all, it is sometimes difficult to stay alert and on course. I felt the boat bump something, which jarred me alert. I felt the bump a few more times and then was delighted to see I had been joined by a pair of dolphins! I decided they must be the angels Rain had sent with me. I was alert the rest of the way to Biloxi.
The next morning I got underway before daylight, leaving Deer Island around 0500, this time with better provisioning. I made good time to Mobile and owing to changing weather decided to charge ahead across Mobile Bay, which can be treacherous. Believe it or not, my angels were with me again, keeping me alert as night fell and I safely made it to Oyster Bay, a large puddle in the next county. That day I voyaged over 18 hours, dropping anchor after midnight. Solar powered! I know people with power boats that won’t or can’t travel that far in a day. Best of all, there was still enough power in the batteries to run the microwave to make supper that night and breakfast the next morning. I was on the home stretch and it seemed I no longer needed the company of angels. It would be another day and a half before I beached at my home port of Molino and called for the trailer.
And that was the end of forty-four days in the sun. A few years later I had a transporter gig in New Orleans. I took the scenic route home and stopped by the High Tide. The place was abandoned and I was disappointed. I’d like to see Rain again, sometime, and tell him about his angels.
They are now making solar modules with power output in excess of 500 watts! Wow, that’s what I need for the Solar Yacht, instead of the 330s I have now. The thing is, you just can’t buy them, yet. The superest, duperest biggest and bestest go to the solar farms. Don’t worry, by the time the Gopher sets sail they will be available, but you’ll be wanting the 600s.
A few years back, someone came up with the idea of making a “microinverter” and sticking it right on the panel. You plug the panel into the microinverter and a big cable runs along the rows, connecting them to 220v. The solar power mixes with utility power and you get a smaller bill. I thought that was a really lame idea at the time, buying an inverter for each module, but the concept has grown on me. Someone dropped off a case of microinverters and a pallet of 300 watt LG panels, so what the heck? I gave them a try. I don’t have a grid-tie agreement with the power company, so I could not use them as intended. I used them in a most peculiar way and found them to be generally satisfactory, especially since I didn’t have to pay for them. Since I could not put them on my power line at the house, I connected them to the MOTOR side of the compressor relay in my outside a/c unit. Using just enough panels to cover the run current of the compressor, I pretty much got free air conditioning. The biggest aggravation with them is a legal requirement that they don’t kick on until the power has been on for 5 minutes. They are coming back to mind, now. I recall they have a communications bus. I need to see if I can use that for another off the wall idea! Can the communications bus turn the modules on and off or is it just for monitoring? Inquiring minds want to know.
Someone has come out with a new idea for hanging stuff off the back of a solar panel. Now they want to hang a battery! That can’t be much of a battery, but it may not be as crazy as it sounds. It all depends on what they have in mind and I don’t have details on that, yet. It interests me because I am now running my grid tie system, with limiting to prevent inter-tie or back feeding, and I am feeding it with battery. Never mind the advantage of being able to take on nighttime loads, eliminating the variability caused by puffy cumulus clouds, UFOs, Black Helicopters and other troublesome shades you can maintain a steady output from the grid tie inverter (GTI).
I’m holding off on a full article on the subject until I collect a little more usage data, but this one change, adding battery to grid tie, is going to knock off roughly 2/3 of my grid usage, which is already pretty low. The reason it doesn’t get 100% is that I have a clothes dryer that my wife is not afraid to use and it can burn about 3000 watts more than the 1900 watt GTI system can provide.
I am going to keep watch for more of this panel-side battery business. In the meantime, if you go with any of this microinverter or other panel-mounted stuff…mount it on the back side! It’ll work a lot better.
I chased one and it wasn’t what I thought it would be.
A big part of living off grid or keeping the power bill down if you are on grid is efficiency. Try as you may to get everybody in the household to turn off unused lights or to not leave the fridge door open, there can still be waste. Some of this comes from “phantom loads” from devices that still use power, even when they are turned “off.”
Our first TV was a big wood cube of a Magnavox. It had no remote. The switch was on or off. Thank goodness, because all those vacuum tubes used an awful lot of power. Today, my TV has a red light down in the corner and it is glowing when the TV is off. Under the covers, there is a microprocessor that is constantly processing. Oh, the whole off-state consumption is less than just one of the tubes in the Magnavox, but it is power consumption, all the same.
Next to the bed there is a phone charger. It always draws a miniscule amount of power. At the kitchen table, the laptop charger is always drawing. The satellite and wifi gear upstairs is always drawing a lot power. My wife’s rechargeable hand vac stays plugged in long after it is charged. I have a shelf full of tool chargers out in the Solar Shed and they all have a light glowing, even when the batteries are topped. Look around your house and you may find dozens of such phantom loads.
Hey, I’m using free solar power, so what’s the problem? It was a big problem when solar was $10/watt. Not so much, nowadays when John always has super deals on solar power, but come a cloudy day, you can get deeper into your battery, which reduces its life, or you might be on the edge of capacity with your inverter.
It may be it doesn’t matter and it may be that you are just obsessive about efficiency. Handle it your own way.
If you do want to track down these little varmints and are on “lockdown”, now might be the perfect time. There are several tools available to help in your quest but the eyeball is cheap and effective. If it has a glowing LED and it isn’t do anything, “sic’em.” The original portable power meter was the “Kill-a-watt.” You plug it in the wall and plug the suspect into the outlet on the Kill-a-watt. The display tells you how many watts are burning away.
A switched outlet strip is the traditional way of dealing with these offenders. I don’t know about you, but at my house it seems that nearly every outlet in use is behind a piece of furniture. The switched outlet strip moves things into the open. You still may decide to leave that load running if, say, your TV wants to reprogram itself after every power interruption. You don’t want to dash in to view your favorite soap opera, only to have to wait an eternity for the programming to complete.
Another way to determine that you have phantom loads is through the instrumentation of your solar gear. My recent battery upgrade to my grid-tie system let me see what was going on at night. Let’s face it, traditional grid-tie doesn’t work very well at night! What IS this stuff going on all night? Power cycling higher, lower, off, and back on. It almost looks like a fridge, but all of my fridges are on the full-on solar circuits.
I initially blamed my laser printer. That thing is possessed, I swear, and find it best to just leave it unplugged. I unplugged and found the instruments reading zero, so I thought the problem was solved. Then it came back, sometimes burning hundreds of watts.
In the “before times” I might have taken longer to track this down, but since we are “in the now” (I have recently watched all of the Mad Max movies, if you are wondering about the language) I went after it.
This involved pulling the big handle on the breaker panel from the grid. I knew what should go dark and what shouldn’t. Now’s time for “the telling.” The outlet for the aforementioned laptop charger was hot and it should not have been. The laser printer was right there, exonerating it, at least from grid power usage. It still isn’t off the hook for stealing wifi. When I got around to the chest freezer and big fridge, they were silent. Aha, what the heck?
It turns out that when I went to move that circuit from the grid panel to the solar panel box, I pulled the wire from the breaker next to it, giving my laptop solar power, but costing me perhaps 60kwh per month on my grid bill.
Well, adding the battery to the grid-tie is covering that consumption, but it is costing me a bit when I can’t cancel some of the power used by the clothes dryer when it is running. It also cycles my batteries a little deeper at night.
Now the question is, do I have room for another breaker in the solar box? In the “now times” it’s “time for the doing.” We’ll just see.
Sooner or later, you gotta do it, whether it is the clock, the smoke detector in the hall, the car or your solar power system. Oh? You have grid tie and don’t have to change the battery? We’ll talk about that, too.
The batteries that I had on the main bank were in great shape, but there weren’t enough of them, especially now that the brutal air conditioning season has begun. One of the auxiliary banks in my EVs was getting punky. I think I got that desulphated and it is feeling much perkier.
No, the main thing is that I wanted to test a specialty battery before adopting them in the Solar Yacht project. I’m a big fan of GC2/T105 type golf car batteries, like Sun’s inexpensive Sun230 model, but dealing with acid and hydrogen generation in a closed area of the boat was presenting technical issues with which I did not care to deal. The easy way out is to eliminate acid and hydrogen generation.
That left a choice between lithium and some sort of sealed lead acid (SLA or VRLA). The cost of lithiums, if considered over the long term, is a great deal, but it is a bunch up front. This boat only has to last a year, and lithium might outlast me. My government funding budget, which is to say my Social Security check, demands a lower up front cost. John sells sealed batteries at a fraction of what they go for at the Marine store (the one out West) but doesn’t have the size I needed for the boat.
I found some used ones from a guy in Georgia. I don’t normally go for used batteries, but since I was testing durability and on a budget, what the heck? I figured I would get 8 for the main bank, four for the grid tie and one spare. The spare would give me an age-matched replacement should one of the others fail and, in the mean time, provide a robust power source for my 12v Solar Boxcar system. (It is actually a 40′ cargo container, but my wife thinks it looks like a boxcar, so it is The Boxcar.)
I thought to do a reality check. It seems that you can’t actually put 13 of these in the bed of an Avalanche. If you could, you’d break the axle. I settled on 9, which fit nicely and was only a wee bit over gross weight.
It was a nice outing for my brother and me. With Andy navigating, the 514 mile trip became 667miles, but we saw some interesting countryside. Two blocks from our destination there was a minor fender bender. Minor for us, that is. I got a silver smudge on my trailer hitch ball, which tore the fascia off the front of the RAM that rammed us. After acquiring our load, we headed to Talbot County, where I showed bro an old cemetery in the bounds of the old family plantation. He’d not seen it, before. I sprayed 200 year old tombstones with tombstone cleaner and he learned a little genealogy.
On the way to another family plot in Harris County, we passed a new solar farm under construction. It looked like progress may have been halted by virus worries. There were some neat, shiny rows and there were some torn up acres still piled with stumps, but no activity. After cleaning up some more great-great grandparents’ rocks we limped back to Florida, as a tire had gone bad somewhere along the way.
Then the fun began. Saturday, between old coming out and new going in, I moved over a ton of batteries. Literally. Another 500 lbs would wander over to the grid tie project on Sunday afternoon.
I was in luck. I had most of the cables I needed, already. Nice fat 00 cables with marine shrink tube on the terminals. I had to make one cable to join banks, but had the wire and connectors. When you buy supplies like this, always buy a few extra. If I hadn’t had these, then I would have been delayed for a week or two, waiting for them to come in the mail.
Overall, I only had to switch the house to the grid for a few hours and everything came back online without a hitch. It really pays to check everything twice, from voltage to polarity.
OK, listen up! This is where we get to the educational stuff.
The main bank is two strings of sealed VRLA batteries and the two auxiliary EV banks, when they aren’t elsewhere, are flooded lead acid (FLA). THEY HAVE DIFFERENT CHARGING CHARACTERISTICS. Time to reset the charge controllers.
Let’s go back in time a bit and I will tell you why I have been hesitant about sealed batteries. Tom, my nearest solar neighbor to the west (12 miles by air, 20 by road) bought 3 strings of the nice Outback VRLA batteries. He connected them to a 10kw array and fried them within two years. There was way too much charging current. There IS a specification for that. After some experimentation, I was able to bring most of them back. One gave its life to science. OK? So, you see that I am not wanting to kill my new batteries.
Reading the fine print (always RTFM*) I learned that you should not exceed 40 amps charge rate per string on these new batteries, should float them at 54.4 volts per string and you can bulk charge for a while at a higher voltage. Now the fun begins because I have 4 charge controllers, three different models and I haven’t been into the menus of two of them in quite a while. I set the twins at 54.4 and 54.3. I offset them a little so they don’t just drop out at the same time. Another controller had a menu selection for VRLA battery, but it has only one button and you have to combine short and long pressings to get where you want to go with it. Mo’ buttons = mo’ better, I have decided. Then there is the FM60. It is wonderfully adjustable, but there is a password and there is a trick to getting into hidden menus. Hint: shut it all down, press and hold the correct TWO buttons and turn on the breaker to the battery. There’s a whole new world of menus in that thing! Save yourself some grief…RTFM.
Next morning, I kept a close watch on charge rates and float voltages. All was well. Nailed it!
What about the EVs? They will be perfectly happy with the VRLA settings, but they won’t get into the equalization stage. They will have to be taken offline every now and then for equalization, which is basically a quick overcharge. DO NOT equalize sealed batteries! They burp out the gases, which cannot recombine to replenish the electrolyte. They dry up and die a horrible death. You mourn their death when you have to buy more. Don’t kill your batteries.
Now, as for the Sun230 batteries that I moved to the grid tie system, I think I will save that story for later. If interested, do your homework and look back through the blog for the GTIL or grid tie limiter stories. But yeah, we’re gonna put batteries on Grid Tie.
Spare, extra or redundant, call it what you like, chances are you are going to need more. Oh, yeah, there’re fuses and connectors and such as that, but I’m talking about wire and cable, here.
When I was a young broadcast engineer at WCOA, Pensacola, I engaged in a total rework of its broadcasting facility. It was tricky, since the station had to stay functional while the new stuff was being installed. An important part of the installation was the rewiring.
At one time I could have told you exactly how much wire I pulled. I can’t now, but I can tell you it could be measured in miles. I handled so much wire that my forearms broke out in a rash from the PVC oil in the insulation. Lots of wire went everywhere there was a studio, including lots of spare wire. Every room had a junction box and active cables went to rack mounted patch bays. In addition to the normal arrangement, any studio could be patched into any other studio, for whatever purpose.
Well, plan as you may, you can’t think of everything, so we ran lots of extra wire in every direction. Sure enough, those extras started getting used. Amazingly, all the extras from Studio A to the AM control room soon got used. No problem! We’d just route through another room.
That kind of thinking stuck with me into my computer career. Every room in our new headquarters had cables going to a patch bay in the computer room and, sure enough, it wasn’t long before things started getting routed all over. Then came that new-fangled arcnet and ethernet stuff. We hadn’t even conceived of that when we built the place, but had left available access and pretty soon every room had both.
The same sort of thinking ahead can pay off in designing your solar power system, too. My Solar Shed is 200′ from the house, so it is a major pain to run a new line, especially considering there’s a water line in close proximity. In addition to the main power line, there is a conduit containing 5 cables, which are now in use, and a spare, empty conduit.
My limiting grid tie experiment is progressing and because of the versatility of the extra cables, I have been ok, so far. I am considering that empty conduit, but pulling stiff wire through 200′ of conduit is easier said than done. I actually have some 10″ and 12″ concrete pipe that would have made a wonderful conduit, had I thought about it. Boy, could I get some wire through that!
For an ordinary installation, you probably don’t need huge conduit, but consider putting in some extra cables and empty conduit. Sure, it is an extra expense if you never need it, but getting a trencher or backhoe to install new work without cutting up the old stuff can be expensive and even perilous.
OK, so your modules aren’t 200′ away, they’re on the roof. It will be pretty easy and cheap to install a combiner box that is a little bigger than your minimum requirement and to put a few extra runs of solar wire. Maybe even put in some small control or sensor cable in case something comes up where you want to monitor temperature or something else up there.
Leave access, too. My solar control room is also now my Man Cave. The ceiling and walls are all closed in where you can’t see the wires. There is yet another expansion of the Solar Shed planned, which may add 50 to 150 more modules. That means lots more wire, but it isn’t a problem. Wall panels around the control panel were installed with screws, so it will be easy to get the new wires run. The wall effectively becomes a raceway and raceway is much easier than conduits for channeling big bundles of wire.
The point of all this is to say, “think ahead” and make it easier on yourself in case you can’t think of everything.
I wrote the material below quite a while back and it somehow fell through the cracks. I have since gone through a couple of variants of a Zero Export Grid Tie system, including a new one this past weekend…and the power company’s meter hasn’t budged since! Read this to get up to speed and there will be more on the latest changes.
The season is changing and so are the solar connections at the Solar Shed.
Grid Tie can be the cheapest way to get into solar and can even turn a profit for you in some places. In other places, the system is rigged.
A much cheaper way to do Grid Tie is a Zero Export Grid Tie (ZEGT) system, using solar power mixed with grid power to run your loads, but not to back feed into the grid. I call this “house tie solar.”
Why is this even a “thing”? Why not just grid tie, using the grid as a virtual battery? Straight grid tie with net metering is a great deal where you can get it. Daryl, in Texas, has a great deal on grid tie and his huge system actually makes him an income stream. A lot of places you can’t get it, though. A lot of places where you could get it have changed the deal. Bruce, in Pennsylvania, ran into this. He’s the one who reminded me of ZEGT.
Let’s say you live in Alabama. I think a recent article said they have $50/month tie fee and it is going up! Here in Scenic West Bogia Heights, Florida, that’s sort of the same sort of deal, but ours is higher if you can even work it out. You pay for a bunch of extra metering equipment and an electrician to install it. Your solar system has to be signed off by a certified tech. Then, on a monthly basis you have your basic $40 connection fee and a $60 solar fee. That a hundred bucks of power bill before anybody gets any power.
Turn on the juice and all the power that you make and don’t use at the time goes to the power company for less than 4 cents. At night, you get to buy your own power back for 13 cents. I am no math genius, but I think under these conditions it will cost you more to have solar power than to go without. Maybe we should run some numbers on this.
Let’s say you use 1500kwh per month. You build a grid tie power system that can supply 1500kwh per month. At 13 cents that’s $195 from the power company. Now let’s figure that the a/c and fridge and the miscellaneous loads (like the clock you can’t set on the DVD player) will use 500kwh in real time, reducing the intake from the power company to 1000kwh, which at 13 cents is $130. 1000kwh of your excess daytime power went to the grid at 4 cents per kwh. You get a credit of $40 off the $130 net grid import, so you have to pay $90 for your power. You also have to pay another $100 for the meter and solar fees. That makes your bill $190 with your grid tie connection. Without it, your bill would have been $195 plus the $40 meter fee, or $235. Ok, so you did save $45. Did I mention that West Bogia Power and Light also requires that you buy a multimillion dollar insurance policy to indemnify them should your dinky little power system damage their grid! The average squirrel can cause more damage to their system than a proper grid tie system can! Hold on, now, I have a solution or two for you.
First of all, and this costs little or nothing, change your ways. If you use more of that solar power before it leaves the house, then they don’t pay you 4 cents and charge you 13 on the power that goes out and comes back. If somebody is home during the day, do the laundry and baking then, instead of in the evening. Set the thermostat for more run time during the day instead of at night. If no one is home during the day, is someone close enough to come home and start the dryer? If nobody can make it home during the day, start a crockpot meal before you leave for work and set a water heater timer to heat during the day. Look into smart appliances that can be controlled with a phone app while you are away!
Having shifted your loads a bit, you are now burning 1000kwh of solar and 500kwh from the grid. You are also selling 500kwh to the grid. That comes to 500 x 13cents to buy, 500 x 4 cents to sell for credit or $65-20= $45. Now add in the various fees and the bill comes in at $145.
Let’s review. Your bill without solar would be $230. Your bill with the first grid tie example would be $195. Changing the routine a bit the bill with solar is $145. OK, I think we are getting somewhere. What else can we do?
The availability of ZEGT can help get new prospects into solar and can help get folks who have had the rules changed on them get back into a profitable state.
Let’s go back to our example, only now no power is backfed to the grid. We CAN make 1500kwh, but we still only use 1000kwh during daylight hours. We discard the excess capacity because we are not exporting to the grid.
As with the previous example, we are importing only 500kwh from the grid. Again, that’s $65 for power, no credit for exported power, $40 for the meter fee and NO SOLAR CONNECTION FEE. That makes the bill $105!
Let’s try that in the example before changing our ways with power consumption. I believe we were using 500kwh of solar, dropping what we buy from 1500 to 1000kwh. That’s $130 for the power you buy, plus the $40 meter fee, for a total of $170 as opposed to the $195 you were billed when the power company was “buying” your excess power!
As usual, your mileage may vary. Your power company may charge more or less, pay more or less and have different requirements and fee structures. Zero Export may or may not be for you. A lot of you have banged on the calculator and are now wondering what it is going to take to build your new ZEGT system or convert your existing GT system.
If you have an existing GT system, RTFM. That’s right, read the fine manual for your GT inverter. Many, especially those made in the last few years, have this capability built in if you add a device to monitor the power line and report back to the inverter. These go by various names, often coming in the form of a power meter or electricity meter, originally intended to just let you monitor your system. Two current transformers slip over the grid lines coming into your breaker box. They connect to the “meter”. The meter has an RS485 (or other communications standard) that connects with the GT inverter. A few changes are selected from the inverter’s menu and now the inverter knows when the solar power need to get in and out of the mix to match the consumption, when possible, but not overdo things and send power out. Hence, you can tell your power company to pull the extra meter and discontinue grid tie.
If you do not find anything on export limiting in your manual, check out a company called ELGRIS. They have an export limiter that they claim works on a lot of GTI models and may have one for yours.
Now for new solar users, hold on. There are reputedly some inexpensive modules that will do the trick and installation is pretty easy. I say reputedly because I have not personally tried it, but I have heard good things. I have ordered two units and will quickly get them installed on my minigrid for testing the ZE claims. If that goes well, then I’ll go live with them and report results, like whether or not the power company busts me for backfeeding. Tom got a visit from the power company within 2 hours of inadvertently backfeeding his system, so going up against West Bogia Power and Light with these new gizmos is a really good test.
We have some new buzzwords in our vocabulary and a new normal. Self-isolating and social distancing.
Miami is kind of a hotspot in Florida, so John has the store closed so everyone can stay safe. Roberto is manning the phone, though, so if you need something you can still get it. The phone transfer mechanism leaves a bit to be desired as far as sound quality goes, but I had a chat with Roberto and if you need to deal, you can get it done.
I also had a chat with John. He is hunkered in place in his concrete bunker, I mean condo, there in Ivory Towers, overlooking the idyllic land of flamingos. I think he is going stir crazy, wanting to go to the jetty and commune with the manatees, but with John it is hard to tell. You’d think he’d write some new blogs! Get with it John! He anticipated me, so check out his latest rantings.
A natural question is “what are you doing”? A lot of people are comparing notes. Well, I am doing pretty much what I always do. On a farm there is about twice as much that needs doing as there is time or, in my case, inclination to do it. Self-isolation is pretty much my normal state. My wife goes out and collects the germs and brings them back so I don’t have to.
I do go to town every week to donate platelets. Blood banks are in low supply due to cancelled blood drives. I figure I am safe enough there, with everybody wearing gowns and gloves and swabbing everything with alcohol. Safe, that is, unless Eman is there. Treat her right or she can and will hurt you. You might consider a trip to your blood bank. Don’t worry, Eman only works in Pensacola.
Now, since this is a solar blog, why don’t I point out some solar-y things you can do while you are at home?
Spring has definitely sprung. The pollen has coated the panels and the berries are making fruit. We usually have a late freeze in March, but not this time. And no rain. What that means is the thick yellow pine pollen, mixed with a little dew has caked on the modules and is reducing the output a bit. Well, we can’t have that. I took a broom after the lower panels in the experimental banks, but it did little good. I am hoping for an afternoon shower to wet them so I can get after them with a long-handled scrubber tool. Otherwise I will have to drag enough hoses out to use tap water.
I had a feed pipe to my water-powered pump come loose, so my water pressure is slowly coming back after repairs. It was an easy fix, but there was a large water moccasin guarding the pipe. That kept me looking over my shoulder. You can shoot a snake and he will slither off before he dies, or you can miss him and he will slither off and make plans to get even. Sometimes you aren’t sure of how it went, so you just stay wary. Water mocs can be mean and aggressive.
I suppose I could also work on my solar water pump, Version 3. The first two were nice, except the submersible pumps quickly died when submerged. Hardly seems right. Just need some fittings and a round tuit to do that. A simple rack of treated lumber has served to hold the panels, recycled 34 watt solar shingles. A lot of times, you don’t even need a charge controller and a battery for a solar pump. Version 3 will have a pump that does not live underwater. I have learned that lesson.
If you have solar, there are the mundane chores you can tend to. Water the batteries, tighten battery terminals. Equalize the batteries. Change the oil in the backup generator and give it a test run. Tighten connections on your charge controllers. Check your instruments to see that everything is really working. Take a look at those MC3/MC4/Tyco connectors to make sure they are tight.
Oh, and if you can see the back side of your panels give them a look. It seems that in the big solar rush of 2010-2012 some substitute materials were used for backsheets and they can break down, leading to eventual failure. How old are your panels?
Some time I will do a piece on repairing modules. Even if you don’t have a backsheet issue, you should check for hotspots. I had a panel with a hot cell that discolored and cracked a 6 inch square area on the backsheet. If you find one of those, take it out of service until you can repair the problem or replace the module. I think I had a bad diode cause my hotspot, but shading and leaves can cause a problem. That’s another reason I need to keep the pollen off, because a lot of the modules in the experimental rack are not even mine. When I get to it, maybe some time I will do a piece on repairing modules. You may have seen the article I did on how to destroy them.
How about a new solar project or upgrade? I finally found some specialty batteries I can use in the next phase of my Grid Tie Limiter project. So I will dash out this week to fetch them, wishing I had a bigger truck to carry more. More on that, soon.
Finally, I did a little fun project with old solar panels, dead ones. Out at the Solar Shed, rain has been getting on the door to the Man Cave. It is cypress and it shouldn’t matter, but it swells up a bit and makes it hard to work. I took a couple of “inert” solar shingles and fashioned an awning. It was easy and it looks great. Eventually I will use them to build a carport for the farm EVs, but this was just a quick job. While I was at it, I added a couple of pecky cypress planks to serve as trim.
So, what kinds of solar chores and innovations are you doing while holed up? Peruse the Sun Electronics website for inspiration. If you want a good chuckle, compare John’s prices to other websites. I guess they can fool some of the people some of the time!
The homes of my grandparents were special places when I was a kid. Bro and I went by the former Collier house on a recent trip to Lake City, Florida. It was a sad sight.
The big camphor tree, where Dad had his tree house is now just a stump. The yard is grown up. The house looks shabby and gutted. The old houses of Lake City had a great architectural element in their pressed tin roofs. You never had to replace them if you just sent somebody up every 10 years with a bucket of silver paint. The roof has been replaced with asphalt shingles. I guess the more recent owners didn’t get the memo about the silver paint.
The house was built sometime in the 19th century, but I don’t know when. I know Lake City was around during the Late Unpleasantness because the residents got even with Yankee soldiers by throwing their rifles in the lake across from the boarding house while the blue coats were having lunch. True story. A few years back they drained the lake and found the guns!
Does Grandmother’s house date back to then? Dunno.
When the house was built, it had indoor plumbing, consisting of a pitcher pump at the kitchen sink. When city water and sewer came along, a bedroom was converted to a bathroom and later another bedroom was added.
Electric lights, a fridge and an electric range replaced the lamps and the icebox and the kerosene stove gave way to an electric range. The kerosene stove used a large glass jar as a fuel tank. Yikes! Central heat started out as an oil burner and later a gas furnace in the dining room, the center of the house. By the late 60s there was a window a/c in the dining room, as well.
We get a taste of something new and better and we want more of that new and better stuff. Human nature.
They discovered the same thing at the DelcoLight company in the 1920s-30s when light plant salesmen fanned out across the country side. They’d show up around sundown in a Model A Ford with a light plant stuffed in where the rumble seat would normally be. They’d give a little pitch about how better light would make it easier for the kids to study.
Yeah, they’d go to the Moms and save the kids. Worked every time. Once they had a foot in the door, they’d go on about all the other wondrous things you could do with electricity. Save time and labor on pumping water. Fresh water would make the cows give more milk. Oh, and you could have an electric cooler to preserve the milk. Oh, the wonders of electricity!
Then the guy would go out to the Ford and drag out a long cord with a light bulb. He’d put that in the parlor and turn the switch. Behold! Let there be light! The electric bulb, dim by today’s standards, outshone the oil lamp and clinched the deal. It would not be long before the house was wired for more than just a single lightbulb hanging on a cord from the ceiling. We always want more.
As I have grown my solar power system I have added more and the bill from the power co-op keeps getting smaller. We are now up to 3 refrigerators and a chest freezer. I’m charging 2 EVs and a boat, which in turn share their batteries. The two central a/c units are on solar. Welding and woodworking are solar powered, as are the chainsaw and other commonly used tools. The Man Cave has a rudimentary home theater and is getting a/c.
More, more, more. My inverter is getting toward its limits, as is the battery stack. Well, I can always stack more batteries and I have a bigger power module I can stick in the inverter cabinet when the time comes.
The moral of these ramblings is “Plan for Expansion.” If off grid or hybrid, get the biggest battery pile you can afford and not one of those dinky, toy Powerwall thingies. Get an inverter that can be run parallel with another so you can double up, later. If gridtie, you can add more solar strings and inverters to cover the bill.
Did you ever read, “A Tree Grows in Brooklyn?” I can’t remember if I ever did, but I know I had the book. If there is a tree there, I’m sure the dogs appreciate it. There probably isn’t much solar power on the neighborhood level in Brooklyn, so all is good.
There are lots of trees at my place. It is a tree farm, after all. The blooming Paulownia grove is a delight to the senses, right now. The pines, the ones the beetles aren’t eating, are clogging my lungs with pollen. The green pickup and the blue solar panels are yellow with the pollen. Then there are those danged oaks I have killed every year for the last 3 years. THEY are putting out again, indicating maybe I didn’t do such a good job of killing them.
I have talked about these before, but I feel like venting again.
Why am I trying to kill them? One is to the north of my array and the canopy does not hang over the panels, but the arc of the sun is such that it gives a bit of shading on a couple of banks, midsummer, when I need all I can get for air conditioning. I’m adding MORE a/c in the form of a mini-split for the Solar Shed’s control room/Man Cave. It hit 95 out there yesterday when I was working on taxes. That’s starting to get too warm.
The other big oak is off to the east and causes a slow start to the power production in the morning. The original phase of the Solar Shed was only 16′ long and was not affected, but the shed has grown and is getting near the canopy.
Dad used to kill the oaks in the planted pines two ways. They had a backpack-mounted machine called a Little Beaver. It would gnaw the bark away around the tree. This is called girdling and it interrupts the flow of nutrients.
They also had a thing that looked like a bazooka. You’d bang a pointy beak into the bark and pull a trigger. That dribbled in a dose of Agent Orange, as they called it in Southeast Asia. Agent Orange is the good stuff, but Home Depot doesn’t carry it, for some reason.
Well, I started with girdling, using the solar chainsaw. I have girdled a second channel. I have attacked the trees with a flamethrower. I have axed away all the bark between the two channels and charred the raw wood. I have bored holes in the trunk and roots, filling repeatedly with herbicide. And a different herbicide. And copper sulphate. The trees are filling out beautifully with the new leaves.
So why not just cut them down? Listen up. I was a Boy Scout, a half century ago before they ruined Scouting. I have skills. You put a bottle cap within range and I can drop a tree right on it. The rules for tree felling do not apply, though, when near expensive stuff and they totally go awry if there is a video camera running.
Therefore, I have turned to just plain killing in place. When you can actually get the tree to die, the smaller limbs fall straight down and the larger limbs come in pieces. You end up with the central trunk, which is easy to handle.
My next step will be to pour rock salt around the tree bases and to call my crop duster friend Rex. He has a reputation for killing every living thing in two counties whenever he goes up with a load of Roundup. He also managed to kill a 50′ swath of trees with an emergency dump of fertilizer at my place, last year. The man is death on wings.
If there is any point to this rambling, it would to be to advise you to take care of the tree issue before you start putting up panels.
It has been in the 80s here for a week. When the nights were still dipping down low enough at night the house would stay cool enough. Not now. It is time to fire up the a/c. The solar-powered a/c.
I have written about combining solar and a/c before. Go back in the blogs to find the articles. I’ll update some things, here.
The house started getting undeniably warm, so it was time to get the a/c going. Normally that would just be the flip of the switch, but I tend to mess with stuff. Last autumn I was rigging the heat pump (downstairs unit) to run on solar when I bumped something or knocked something loose. The heat pump would not pump heat.
Well, no worries, I have not used it in years, anyway. Not for heat, at least. I have an outdoor wood furnace that runs on beetle-y trees I need to cut down anyway. It is super efficient and costs practically nothing to run if you have an unlimited supply of wood and a solar chainsaw. The current generation of 40v and 80v rechargeable saws is great! So I just forgot all about the heat pump, having other things to do.
My first attempt at firing up the a/c (upstairs unit) yielded nothing. The downstairs unit was missing the lockout relay, so nothing was working. I replaced it and life is cool.
If you are planning a house, consider inverter or variable speed units. If the layout is simple, consider mini-splits. Here is why.
These things are super efficient. My rattly old units were “hi-efficiency” at SEER 13 when new. These inverter units run 18-25 SEER. That means a low power consumption even if you don’t have solar. If you do have solar, there are more benefits in not having to have as many solar modules, batteries, charge controllers. You don’t need as big an inverter. A friend and I remodeled a carriage house in Georgia, replacing two loud, inefficient SEER8 window units with a 2-head mini-split. It is awesome! It doesn’t start and stop. It speeds up and slows down. You don’t even know it is running most of the time.
A conventional a/c compressor starts up with a tremendous power surge. My sturdy 5kw inverter would not start either of my conventional units. An inverter a/c eases its way into operation and the inverter barely knows anything is going on.
Wait a minute. Time for definitions. My 5kw inverter is the big box that turns the solar DC volts into household AC volts. The inverter in the a/c is a variable speed controller. Got that?
You either make it easy on your solar equipment or you buy more of it. Maybe better to spend a little more on the a/c than a lot more on everything else.
Here is a curious thing. A/C guys don’t seem to like variable speed split units, though the mini-splits seem to be catching on. There is more potential for something to go wrong and I think most of the techs are simply not comfortable working on them, yet.
In the meantime, if you have a legacy system, there are things you can do. Add a Smart Start device. It connects to the contactor and condenser in the outside unit, allowing the compressor to start up over 2-3 seconds instead of instantly. My 5 kw inverter does not even grunt and it settles down to a 2kw load to run the a/c.
Normally the upstairs unit, set to 71 will keep the downstairs at the target 75 degrees with no problem. Last summer, when temps frequently hit over 100 degrees, it needed a little help. I did not think it a good idea to run BOTH units at the same time, especially since the inverter was in a room that typically ran 135 degrees during the day. A LOCKOUT RELAY was installed in the downstairs outside unit. This is a simple 24v single pole double throw relay that activates when the thermostat operates that unit. When the relay clicks, it interupts the thermostat line to the upstairs unit.
Use programmable thermostats! Oh yeah, that was something else that hindered my startup. The thermostat needed a new battery. Anyway, the programmable thermostats let me set the house much cooler during the day when the free power is shining and then back off at night to save the batteries. Yes, we did have to run some at night when the temps never dropped below 80 after being 105 during the day.
Downstairs gets a boost from its larger unit, but only when needed and I don’t have to upgrade my inverter. Of course, I still need to fix the downstairs unit that I broke. Always something.
My brother and I drove across Florida from Pensacola to Lake City on business. It was good to put faces to the voices we knew from the phone calls. What we were not expecting to see were thousands of solar panels. The last few times I’ve been across Interstate 10, all you’d see of note on I-10 was the devastation of Hurricane Michael.
Suddenly, I realized something and told Andy, “Hey, we own that!” At least we own a few hundred shares of the company that owns that.
That Florida, the alleged Sunshine State, has solar farms is not unexpected. Suwanee County is timber country and was not devastated by the hurricane. They did have some pine beetle problems, so maybe they decided to get out of the pine tree business and into power.
I found some newspaper clippings and was surprised to see how quickly it had happened. NextEra started the approval process something like a year and a half ago for a solar farm that is to be built a mile from my place. There was a flurry of activity last year with surveyors and such, but not the first post hole has been dug. You just wouldn’t believe the regulatory hurdles involved!
Financing is always an issue and so is material supply. So many solar farms are going in that the module plants are running flat out with backorders. Folks who use import panels are now having to deal with China essentially being shut down owing to the Wuhan Flu. It is always something isn’t it?
On the return trip, as we drove west of Tallahassee, approaching Marianna, we were back in the hurricane zone. Millions of pine trees were broken off half way up. Acres of land were layered as high as a house in wood chips made from clearing all the downed trees. This seemed an area suited for a new solar farm. The entire power grid was wiped out in this area, so they had to start from scratch. Have they incorporated Solar-Plus-Storage in their plans? Don’t know, but it would seem a good idea.
More notable than the solar farm we saw and the place I thought would be good for another one was the total absence of rooftop and backyard solar. Maybe we just didn’t see it from the Interstate. Again, if you are rebuilding from scratch and had gone through a period of months without power, you’d want solar, wouldn’t you? Perhaps the priority was to get a roof and solar will come later.
If you do decide to go solar, YOU should not have to worry about the kinds of shortages that concern the big boys. John does not generally import the Chinese modules and much of what he buys comes from factory closeouts, bankruptcy auctions and used panels from decommissioned arrays. You’d be surprised how much of that stuff is around when you have a solar bloodhound like John on the hunt. Sun Electronics always seems to have a good inventory at great prices.
I don’t watch much TV, beyond the network evening news. I was in the kitchen eating when my ears perked up about something solar on 60 Minutes. Then I heard Rocky Mountain Institute mentioned. I had to watch.
You’ll recall that a Cat 5 hurricane clobbered the Bahamas and just smashed the Dickens out of parts of it. Traditionally, power in the Bahamas comes from a Diesel plant on every island. Fuel deliveries are ever a logistical challenge. I’ve not personally seen that in the Bahamas, but I did see it in the Caymans when I was a computer tech back in the last century. The power made by the Diesel plant was fairly dependable, but not really “clean” the way computers like it…hence my island visit.
60 Minutes didn’t talk much about the Diesel generator, except that it was over yonder and most of the users were here, 20 miles away. Not a power pole was left standing in between. I am betting the big engines ran just fine. The problem was how to get power from yonder to here. It would require new poles and lines, like folks didn’t have enough other stuff to worry about.
Then somebody came up with the idea of microgrids. Put the power source close to the users! You can still tie microgrids together to make a big grid, too. The plan is to put a few acres of solar here and a few more over there until everybody has some.
Enter the guys from Rocky Mountain Institute. Google them when you finish here and download some papers I am going to tell you about.
You say they are going to put up solar panels. Didn’t nearly every house on the island just get flattened? How are solar panels going to stand up to 180 mph winds?
That’s where the Rocky Mountain Institute boys come in. A while back, they studied solar panel failures after storms. For the most part, the failures were either caused by flying objects or the panels themselves became the flying objects, causing more havoc. They concluded that it would be a good idea to mount your panels well enough that they stay put and do not become flying objects. They are taking it a step further on the island system, mounting them very low and skirting the to keep the wind from getting under and lifting them.
Duh. Well that may seem obvious, but nobody had really analyzed installations and failures to see what that meant. Turns out it isn’t that complicated to tie things down and a lot of common practices need to be changed.
You can find the Rocky Mountain Institute website and download the free pdf report for all the details, but I’ll hit the highlights. Oh, I should warn you…there will be graphic photos of smashed and twisted solar panels. It’ll break your heart.
So many times you see one clamp between the edges of two panels and a bolt going down between them to the frame. Don’t do that! Use separate clamps for each module.
Don’t hold things down with screws. Use bolts.
Make sure your supports are firmly in the ground.
That’s just hitting the highlights, but it makes sense. It really doesn’t take much to hold the panels down under normal conditions. When the hurricane comes, the challenge is simple, though: keep the panels in place.
To avoid wasting land for mounting solar panels, a lot of microgrids try to use rooftops. Keeping a rooftop in place can be a challenge and a necessary part of installing solar. Many of the same techniques apply to rooftop solar, but the challenge has to include keeping the roof in place. Keep the roof in place and chances are you can still use the building after the storm! RMI just finished a paper on rooftop system survival, so be sure to download that one, too.
To emphasize their point as to the value of microgrids, they used Puerto Rico as an example. After the total destruction of their grid, solar microgrids were installed at schools. The recent earthquakes knocked the grid down, again, but the schools and other buildings so equipped had power. Hurray for solar!
Another point made in the story was that building a solar power plant is now pretty much on par with building any other source. Batteries have come way down in the last few years, though we individual users would surely like to see some more breakthroughs.
I look at my own system and really, really hope we don’t get a hurricane. We are overdue, here, near Pensacola. My recycled solar shingles are only rated at 60 mph. That’s just tropical storm level. There was an optional clip that is no longer available, but I could replicate it, sort of. The problem is there are hundreds of panels and not all of them are readily accessible.
Most of my conventional panels are on temporary mounts for some of the cockeyed tests I am running. I know they could be better and they could be easily bolstered or just taken down in a few hours. The entire mounting structure is wood. Wood has some give in a stressful situation, but it is all very high and there are no bolts. The framework was put together with a nailgun to get started and long deck screws were added to strengthen the bond. Metal straps would be better and maybe they will get added.
After reading the RMI reports, I am a bit nervous about my own installation. Upgrades are not out of the question, but it is quite obvious that it would have been a whole lot easier to put them in place during construction and they really would not have cost a lot extra.
How would you rate the survivability of your system?
Kris Kristofferson had a big hit with a song on that theme. Instead of moaning about why things had gone so wrong, though, he was wondering why good things had happened when he felt he didn’t deserve them.
Well, things can go wrong in your solar power system, just like anything else, and you’ll have to get off your wallet to fix them. You can ask, “Why me?”, but if you are just feeling sorry for yourself it’ll likely happen again. If you ask “Why me?” constructively, that is to say, analyze what you might have done differently, you might end up with a better and stronger system that won’t have such a failure in the future.
Here at the Solar Shed, I have all kinds of experiments running. Many are temporary, but sometimes stick around longer than expected. If I get sloppy on these temporary rigs, then it can get expensive. Also, different circumstances seem to offer different “learning experiences”.
Example 1–Do you know what the schematic symbol is for an antenna? Visualize an upside down wire coat hanger and you have a pretty good idea. If you have 3 solar modules in series, you can twist all the wires together and have the pair for the downline together or you can have them take the shortest path, with ends up with a more or less triangular circuit…just like the antenna symbol. Now, a loop antenna is directional, so if lightning hits the tree over yonder, the induced current from the blast may be out of phase and not bother your system a bit. OR it may be 90 degrees around and channel the hit right into your system, which can get expensive. Trust me, I know this to be true. Keep your wiring tight and not looped.
Example 2–If you do not have a surge arrestor on your system, you should not complain about a surge getting in and causing havoc. In the spring time, we have some really nasty lightning storms around here. I mean, go hide under-the-bed-with-the-cat-bad storms. In a case of Example One and Example Two combined, you may discover interesting things. For one, a charge controller might NOT be injured by lightning, but because it operates slowly it can pass it along to your inverter. The inverter monitors its output and adjusts according to the input with which it has to work, but this adjustment is not lightning fast, so you can get some really interesting effects. One brand of inverter I had online would blow its display board. It was the weakest link and it took the hit, saving everything else. It would run just fine without the board, but I had spares. After a couple of times of this, I was out of spares and decided to run without display. I had other meters. I did, however, lash up an output surge arrestor. Good thing. The next storm did not kill the inverter, but it wiped out the feedback loop, so it got the urge to keep making lots of voltage…lots more than is considered socially acceptable. Fortunately, I had put in that output surge arrestor and only it went up in smoke. Otherwise, everything in the house on that circuit would have been destroyed. The saddest part of the story is that my new 48v system, not yet online, lost its big 12kw inverter. Have you priced a 12kw inverter? They cost a lot more than surge arrestors! I think the system packages that Sun Electronics sells pretty much have arrestors in the kit, but ask. If building a system a la carte, install surge arrestors!
Example 3–Nothing bad happened, here, because I was prepared. Lots of gear has fans in it. All of my charge controllers have them and the Sun King 5548 inverter that I built in the shell of my deceased 12kw inverter recently had one of its fans start getting noisy. There is a manual fan in the top of the case that I use a lot in hot weather and another fan operated by a thermostat on the transformer. That one never runs as I am running 5500 watts on a 12,000 watt transformer. Right down on the driver board, there is a small fan that runs based on the heatsink temperature. This one is pretty important and it would rumble and howl when it started up. In this inverter’s design, heat won’t cause it to blow up, but it will shut down until it is comfy again. Having the lights and a/c blinking on and off on a warm day is really annoying. Folks, when your fans start talking you need to listen. I have a drawer full of fans for just such occasions. I bought two extra when I built the inverter and I have several more dissected from old PC power supplies by an 11 year old who likes to take things apart. Never throw away working fans! If you buy replacement fans, TRY to get ball bearing fans. They cost more than fans with sleeve bushings, but they last WAY longer. The specs, like voltage, current and airflow (CFM) are usually printed on the hub of the old fan. Listen to your fans. They mean it!
Example 4— Pay attention to the meters. I recently pulled a set of 2 year old batteries from the system. Why me? I have batteries 5 years old that are just fine! Interestingly, it wasn’t just one battery with a bad cell. I was hoping to use some of that set in other 12 and 24v systems around the farm, but No-o-o-o-o, they were all bad. Curious. Well, it seems I had two charge controllers that had a bad firmware revision and may have had some damage from all those lightning episodes. Since they run less than half the power for the whole system and otherwise seem well-behaved, I ignored the high-ish afternoon voltages, thinking they were supposed to go that high as part of their multistage charging act. Nope, they were cooking the batteries. Pay attention to the meters. They are there to tell you stuff!
Example 5–Unless you have sealed batteries or some of those fancy Lithium packs, then there’s a good chance you will need to add water to your batteries from time to time. How often depends on how hard and how deep they are cycled. If you pretty much use up the battery at night and have enough solar to charge it hard, you will probably go through a good bit of water. Once a month is probably good for most folks, but that previously mentioned set that died young was going through gallons every two weeks. Keep the water above the plates and use only distilled water. It is only a buck at the grocery store or WalMart.
Example 6–Keep your terminals tight and clean. Terminals just get loose and need to be tightened. Otherwise, they can run hot and waste power or even burn off the lugs of your battery or inverter. Just today, I opened the cover of a charge controller to get to the temperature sensor wire and while I was in there I decided to check the terminals. Two were not loose enough to cause harm, yet, but needed to be snugged up, just the same. On your batteries, you can add the threat of acid corrosion. Don’t let that green stuff build up. Clean it up and coat with grease for protection.
Example 7–Pay attention to the heat. I haven’t had any problem from this, but it got uncomfortable in the Solar Shed’s control room/man cave last summer. There was no ceiling, then, and the backside of a solar panel is hot. The IR thermometer showed 140-150 degrees and the room was routinely over 110, even with the door left open. This had its own issues, like random animals showing up on the couch. The a/c I had didn’t even stand a chance. There is now a ceiling and insulation, so much of that issue is handled. I will be adding a vent fan and, budget permitting, a mini-split heat pump. Mostly the heat pump will be for me. A check of the spec sheets on all the gear indicated we were well under the too-hot mark. If you don’t have temp specs, you can check the equipment itself. Lick a finger and touch it to a transistor. If it doesn’t sizzle, you are good. If it sizzles, you are close to the limit. If you don’t get back all of the finger, then it is too hot and you need to cool things down.
You might thought I have forgotten poor ol’ Will. No, I have been busy and I think Will is now leaning toward grid tie. He has such a big load and the whole purpose of going solar was to save money when he retires. Grid tie can be a whole bunch cheaper than going off grid. In his case, if the grid goes down, he has a whole house generator that kicks in automatically. That gives him a low power bill and a backup supply.
I will continue with the answers, though, because, regardless of the size, many of the steps and advice in this series of posts will be the same for most off-grid situations. It is just a matter of scale.
We previously determined the load, how many panels we need and how many batteries we should have. Today we’ll go over the charge controller(s) that you need to get batteries charged safely.
Except for a super cheap shed system, I almost always recommend a Maximum Power Point Tracking (MPPT) charge controller. Heck, I even put an MPPT charge controller on my new Boxcar Solar system. What’s that all about and what are the advantages?
If you look at the label on the back of your solar module, it’ll have an open circuit voltage that is at one level and a maximum power voltage that is lower. That is really only valid at full sun. If it is overcast, the open circuit voltage may still be pretty high, but the maximum power point will be completely different. The brain in the MPPT charge controller constantly tinkers and adjusts to find the best charge. Not only is that a neat trick, but you will typically end up getting around 30% more power from your panel. That’s something on the order of getting extra free panels, but without having to haul them up onto the roof.
Another neat trick of the MPPT controller is that you can use a higher input voltage. There are all kinds of advantages here. First of all, you could use a cheaper “24v” panel on your 12v RV or boat AND the higher voltage will start the charging sooner in the morning or under cloudy conditions.
Remember, too, that John sometimes has some odd panels from grid tie service that have weird voltages, but they are dirt cheap. I bought a pallet of those 70 watt, thin film panels he sell for a dime a watt. They output 96 volts! You know how a lot of people will test a 9v battery with their tongue? Don’t do that with these panels!
I have 4 of them in parallel on the boxcar. (It is really a 40′ shipping container that looks like a boxcar) The 96 volts goes into the charge controller and comes out as 12 volts to charge the lighting battery. The panels are flat on the roof and in a forest, making for a challenging installation, but it works.
You can also use less wire. Solar wire is often 10 gauge, which in 120v service is good for around 30 amps. If you run 30 amps at a lower voltage you get substantial voltage drop and power loss that can only be cured with more or larger cables. For Stan the Hermit’s system, we put 4 large panels in series-parallel on each downline to his charge controllers. 4 panels do not exceed his power limit and only use half the capacity of the cable, so losses are low.
Now, what about the controllers themselves? They come in all sorts of capacities. I have 4 60 amp controllers on my system. John sells a 250 amp controller that I know of and I think a larger one. In some ways it might be better if I ran the one controller because then it would have all the knowledge of conditions and all the control over the charging. I got in the habit of using multiple controllers for redundancy on my sokar expedition launch and that turned out to be a good thing one time when some rough water nearly sank the boat and killed one of the controllers
In my home system, on a cloudy day or early in the morning, all of the controllers are running flat out to gather power and that is a good thing. Come 10 a.m. on a clear day, it can be possible to have too much of a good thing. You should only hit your batteries just so hard (the C rate) and I have enough solar to hurt the batteries.
I solved that situation by leaving one controller, my nice FlexMax, at factory setting and then step down the ratings of two of the others. That way, when we get into the range of bulk charging the two shut down. I go out at 10 a.m. on a sunny day and the two might be at or near zero output if the load is light. If I turn on the electric heater in the control room, then the dormant controllers spring to life, providing the extra 70 amps DC to the inverter to run the heat, but no more to the batteries.
Some of the newer models have a feature that let you link the controllers together so they can effectively think as one. That’s great, especially if they have a menu item where you can specify just how much battery capacity you have available. It is always best when the system components are working together.
On a system the size Will would need, you’d use the biggest controller you could find and use enough of them to have all that power covered. And, really, the same goes with smaller systems like mine.
I think I mentioned early on in this series that the higher your system voltage is, the more efficient you will be with your charge controllers. Here are some examples. The boxcar system is 12 volts and uses a 40 amp controller. 12 X 40 yields only 480 watts. If used in my 24v boat, then the same controller could handle 24 X 40 or 960 watts. On a 48v system I can run 1920 watts through it. Think how much money you can save buying one controller instead of four!
One last thing I should mention is that MANY, if not MOST, of the inexpensive “MPPT” controllers sold on Ebay and Amazon are not really MPPT controllers. Some are pretty good Pulse Width Modulated (PWM) controllers but not true MPPT. Some are dangerous. There are some bargains, but if you want to make sure of getting good gear, talk with one of Sun Electronics’ sales engineers and they will fix you up with the good stuff.
Going through this morning’s online solar newsletters, I saw some new products that are on the way. This is not at all unusual, but a couple of these things made an impression.
In solar modules, Trina is using bigger cells, but slicing them up and arranging them so you can get 500 watts from a panel the same size as a standard 72 cell unit! Wow, and to think I was drooling over 435 watt panels for my solar yacht! 500 watt panels would give me 4500 watts, which could come in handy to run the bigger motor that it seems I’ll need on my 6000 mile trip. No, I don’t think they are available, yet.
Another thing, a bit more mundane, is a new panel mounting system. Oh, somebody is always coming up with some new kind of clip and maybe I should do a post showing some of what’s in our media library sometime. This new thing is totally unique, though.
Are you familiar with seamless gutters? Bear with me, my mind has not wandered. The contractor arrives with a roll of metal and if you need a 40′ section of gutter along the garage, the roll of metal is run through some forming tools and out comes your 40′ section of gutter. This new solar panel mounting system works pretty much the same way. The trailer is pulled up to your house, the guy on the roof calls down the lengths of mounting channel he needs and the person operating the machine starts cranking out custom lengthe mounting rail. The result is a lopsided U shape channel with ledges at the top. You bolt this to the roof with the higher side down. Then you mount another at the appropriate spacing. Set your modules on the ledges and clamp them down. The channel area is your metal raceway for all the wires.
Neat idea. There’s always something new under the sun.
You know the old saying about one bad apple causing the whole basket full of them to go bad. The same thing applies to batteries. I am there, now, and so is Mark. Like me, Mark seems intrigued by the Simpliphi lithium batteries, but is also interested in getting a little more life out of what he has. Here’s his note.
Ok, since my 8 Rolls L 16 batteries are 8+ years old, all but one (one cell is 20) are reading good PH, would it be better to get 1 battery new or replace with a Simpliphi? How much do they cost and how many would I need for a 24vDC, 3KW 220 volt a/c system used as a backup on house? It’s the old array and battery bank, we have since added a separate grid intertie array but like both.
We will first consider stretching the life of what you have. I am all for that, but I would NOT buy a new one to mix in with the 8 year olds. Have you given them a good, bubbling equalizing charge? Sometimes that will bring them back.
It may be that you can find a good used one at an industrial battery dealer. Stores like WalMart and Target use L16s in the floor scrubbers and trade them out. Maybe you could pick up a used one, and one that is a better match, for a hundred bucks or so.
Another option would be reconditioning. Here in Pensacola we have an outfit called Battery Guyz that will sell a reconditioned golf car battery for $60 with a one year warranty. Reconditioning includes desulfating, washing them out and refilling with fresh acid. Maybe an outfit like that could refresh your L16.
Now, as far as replacing one of your L16s with a Simpliphi…NO! The L16 is 6v. The Simpliphi is 24 or 48v, depending on the model. You can replace your entire collection of L16s with Simpliphi. Could you keep the one good bank of L16s and run parallel with Simpliphi? I don’t know the battery well enough to answer that question. I have the same question myself as I have two 48v EVs running in parallel to my house banks. It is a possibility I would look into by contacting the company. From what I read about the Battery Mangement System (BMS) I think it is a possibility, but you would probably have to separate the L16s offline when you equalized.
Let’s assume the worst, that we’ll have to swap out them all and start with his L16s’ specs. 8 of them on a 24v system is two strings. Depending on which version he bought, they are good for 390 or 445 amp hours. Let’s just round off to 400 since I hate math. 400ah x 24v x 2sets=19,200. Call it 20kw. Now, you can only safely draw down 10kw, so to replace the entire set of L16s with the Simpliphi 3.8kw units, you’ll need 10/3.8 or 3 of them. Because of all the rounding, they may give a little more drawdown than the 16 Rolls. One Simpliphi, I think, weighs less than an L16, and 3 of them will take up a whole lot less space.
Here’s the kicker. The Simpliphi is rated for 10,000 cycles. That’s more than any other lithium I have seen. 10,000 cycles is 27 years. If you are my age, then that is a “forever” battery. And no maintenance.
You’d have to get with Roberto or Tony for some hard prices, but I would guesstimate that 8 shiny new Rolls L16’s, a premium brand, would set you back around $3000, especially if you throw in postage on those heavy beasts. I think the retail on the Simpliphi is around $3000 each. So you end up paying maybe 3 times as much for 3 batteries as the pile of L16s. Yikes! BUT, now you have more capacity, less maintenance, and may never have to change a battery again. Oh, and bet that if an L16 is $350 today, it will be more 8 years from now!
It’s a bunch of money, I know, but if I am running the numbers right, that sure sounds like a bargain to me. Call Sun Electronics to get up-to-date numbers and an actual quote.
Note that earlier I ran the numbers for 16 batteries instead of 8. That gave a completely whacked comparison, but the conclusion remains the same.
His old 12v system, pictured above, is really getting tired. It consists of nearly 50 mismatched modules and two windmills in parallel on a single overworked charge controller! His new 24v system is running, but only half-installed and there have been issues.
After our little troubleshooting session the other day, Stan-the-Hermit left the cabin on the creek for a few nights on the beach. He’d returned to the creek to find his batteries were full for a change. Of course, to zing me, he started out like there was some kind of problem.
Best news of all, for the first time ever, he ran his well pump and got all of his tanks charged up so he could bathe. Normally he has to fire up the generator to run the well pump, but it started and the charge held until all four of his tanks were full and the pump shut off. Given that his inverter is of the modified square wave variety, that’s quite a feat, as motors tend to prefer sine wave inverters.
To review what happened, Stan THOUGHT he had 5 of his 10 300+ watt modules connected in parallel to his 60 amp charge controller. Owing to a bad MC4 connector, 3 of them were actually NOT connected. Just as well, because all 5 of them would have exceeded the capacity of the charge controller. We replaced the connector and reworked the arrangement to two series pairs of panels, which reduced the amperage (and loss) on the downlines and gave the controller a little more voltage to work with in the morning and afternoon.
He swears he will finish wiring the rest of the modules and return my big roll of wire. I hope he remembers that if his 60 amp charge controller isn’t big enough for 5 modules, then his new 40 amp controller won’t handle the remaining 6 modules. I’ll be expecting a call next time the sun comes out.
I knew there was trouble as soon as I saw the Caller-ID. Stan’s system has been under performing, partly because he doesn’t have a decent battery and partly because half of his panels never got connected. Well, more than that, it turns out.
I loaded up my big spool of solar cable and a fistful of connectors and adapters and headed for Canoe Creek. You can’t get to his cabin in a straight line. No, you have what seems like miles of hill and dale and switchbacks. Florida is reputedly flat, but not along Canoe Creek. I know to take it easy and asked myself when was the last time the pickemup got new shocks.
I finally arrived and was delighted to see he was wearing pants. That was probably more in deference to the cool weather than knowing company was coming. If the weather is warm and there is nobody to complain about your wandering around in your shorts, then why not?
One thing I knew I wanted to do from the beginning is put the panels in series pairs to get a little more voltage to the MPPT controllers than just hanging them all in parallel. His is a 24v system so you can get away with it, but I like my way better and he’ll have less loss than trying to run 40 amps through a 30 amp wire.
Remarkably, he got away with just that sort of stuff for years on his old 12v system, which still works.
Stan has more ladders than anybody else I know, so there was one handy to go up for a better look. Just a word of advice here about old fiberglass ladders that have been left out in the weather. They sprout little glass fibers that will cause you to itch like mad if your bare arms come in contact.
First thing I noted was the panels were dirty. OK, mine are, too, so don’t count on 100% of rating. I cut the cable ties loose so I could see what was going on. Two panels were in parallel on one downline and 3 more were on another. Technically, he was running too much power into that 60 amp charge controller, but not really. There just wasn’t that much power. Stan was telling me that at high noon on a clear day he was getting over 500 watts on the meter. These are 305 watt panels. Five of ’em. Dirty or not, there should be more power.
I paid attention as I dismantled stuff. First of all, I cut the switch to the charge controller. That’s what it is there for. Pulling MC4 connectors under load can draw an arc and either burn up the connector or even burn you. So, for a few minutes, I was up and down the ladder, switching off and on and reading meters. Stan could have worked the switches and meters, but I wanted to see for myself what was going on. Know what I mean?
About the right amount of power was coming in on the one downline and not a thing was coming down the other. One of the MC4 connectors didn’t look quite right and it was indeed bad. Maybe it was corroded or maybe it was burnt.
“Well that’s one I got from you!” Stan declared. True. He got it out of my junk box. What happened after I took it out of service was beyond my control, yet the problem was MY fault! Stan must be related to my wife. They think alike.
I cut off the connector and put on a new one and he was back in business with 4 modules instead of two. That’s got to work better. I barely had enough time to get to Pensacola for something I wanted to do, so I told Stan to just copy those pairs 3 more times and he’d be done. I even drew a picture.
Moral to the story? Get everything out so you can see how it is connected. Check every connection. Don’t assume anything. If something seems wrong, maybe it is.
As for finishing up, Stan decided to go to the beach, instead. He still has my roll of cable.
Yes, it HAS been a while since the last post. This time of year just seems to keep me busy.
Last update on Will’s system we essentially concluded he is going to need a huge battery. Batteries should not be a system afterthought. They are probably the most important and expensive part of the system. Do it right and you can minimize having to do it again, unless you can find a “forever” battery.
I know Sun Electronics has several kinds of batteries, because I have been there and seen them. And bought them. The thing is John has all kinds of stuff that never gets shown on the web site until they have a closeout sale. I bet John doesn’t even know what lurks in the back corners. Sometimes it doesn’t hurt to just call them and tell them your situation and maybe they’ll surprise you.
Well, in a conversation with a fellow who got a quote from Tony for a pretty substantial battery, I learned about one that is real interesting. Understand, MY interest because right now I have one bank that is well on its way to ruin and others that are pushing up to 6 years old. I need batteries myself. Golf car batteries are generally considered beginner batteries and the better stuff can cost a lot more. Better can last a lot longer, too, making the expensive stuff cheaper. We’re talking about quality, here.
Well, here’s this lithium battery, the Simpliphi 3.8. It comes in 24 or 48v configuration, 3.8kwh. It is the good kind of lithium, that is they don’t burst into flames. It is much lighter and much smaller than conventional batteries, so if you need a really big (capacity) battery, you don’t have to build a new wing on the house to hold the battery. Apparently the built in battery manager (BMS) let’s you use it like any other battery and, in effect, go to 100% discharge of rated power. The BMS holds the necessary reserve to keep from harming the battery.
So, with a lead acid battery you strive to use less that 50% of capacity to maintain better battery life and the Simpliphi lets you use 100%. That means you have an even smaller pile of batteries in the power room. Throw in a lot more useful cycles (around 10,000) and this battery starts to look economical if you take the long view.
Unit size is 13.5″x14″x8″ and it weighs about 78 lbs. 3 of these weigh about the same as 3 1/2 Trojan T105s and have the usable power equivalent of around 16 of the Trojans! Wow.
It seems there are wall brackets available to fit these batteries, too. Compact, long life, neat installation, no hydrogen or acid fumes and long term economy. What’s not to like?
If you have your own solar power system, you literally own the power company. Heck, you ARE the power company. It can be a big chunk, at first, but over the long term you should save some big bucks. Like the big power company, you’ll have maintenance costs, but at least you won’t have to replace 10,000 poles next time a hurricane or ice storm rolls through. The big power companies know that solar is the cheapest power source now, so follow their lead!
I own another power company, too, or at least some shares of it. First there were shares of one of the local power companies. The GOOD company, not the one that supplies me. Then there were shares in this hot shot company that is buying up other power companies and installing solar farms all over Florida and other places. Then they bought the local power company.
The “financial advisor” says I need to sell some shares. I have too much. It upsets the balance. Maybe sometime I will sell, but here is a company that is making money hand over fist while investing in loads of solar power. Just imagine the profits they’ll have when they finish all the solar farms, quit buying coal, quit buying natural gas and use up their last nuclear rod? Sell? No way. They pay good dividends.
I think it was Don Lancaster who suggested this sort of investing to pay your bills. Invest in what you use. You eat, so invest in a profitable food company. You drink, so invest in a beverage company (this has been the crown jewels in my family for over a century). You wear pants…and so on. So why not a power company? Since most power companies are keen on solar for THEIR use but don’t really want you to have it, wouldn’t there be a sweet irony to you using their dividends to build YOUR solar power system?
Well is there a future in power companies? Some thoughts there: Yes, because not everybody can do their own solar power system. Yes, because as electric cars catch on they’ll need power, too. Yes, because we keep finding more ways to use more electricity. Yes, because they get rate hikes tied to costs, so they are guaranteed to make money.
I don’t use much power from my grid provider, but they charge a lot anyway, because they are corrupt and inefficient. I’ll pay the bill with my dividend checks from the other company. I’ll also keep making most of my own electricity and maybe get to spend what I don’t get billed, assuming I ever quit expanding the system! Maybe I can just put that expense down to “entertainment”, because I really enjoy this stuff!–Neal
Will needs a big solar power system for his big house. We figure he has the perfect slab of roof for installing enough solar modules. Now, since he wants an off-grid system, we are going to think about a battery. A really BIG battery.
No, I have not forgotten about Will and his new solar power system. It’s just, well, holiday season, firewood cutting season and working on my own system season. I have been thinking about it, though, and I’m thinking I’d hate to see Will completely leave a perfectly good grid. But is it a perfectly good grid?
Lots of places in Texas, where Will lives, give grid-tie folks net metering and some that don’t at least don’t try to punish you for having solar. If you have a good power company you can put together a system that will take care of most or all of your power consumption and you’ll still have the power company as a backup. Maintaining the connection to the power company can cost a bit, but it could save you a good bit of expense in your power system, like on the size of your battery bank.
Warning: Your power company might change the deal at any time. It happens all the time. I just saw where one power company figured the value of your grid tie solar power at nearly 8 cents, yet they decided to pay 2 cents for it and charge you a bunch if you buy it back. They might also tack on an extra $50 per month or more just for the grid tie connection. Grid-tie, traditionally did not give you power backup if, say, the power company shut the power off for a week to prevent forest fires. We have ways around all of that, now. We can interact with the grid instead of intertie. More on that later.
Will’s motivation is to save on expenses when he retires. Smart move. What I am going to suggest is a path where he can keep the grid for a backup and eliminate most of the power bill OR cut the cord. It is the same equipment and following this path, except you have more or less battery expense. Your solar panels will provide all of the house’s power, if all the calculations were right, and you can cut the cord to the power company when you are confident about the system.
Let’s start out, though, just planning our battery size for going off grid. I find that being able to go 4 cloudy days is a pretty good reserve. On a cloudy day, you might only get 10% out of your solar modules. If it is cold then the batteries might get a little sluggish, too.
I came upon the number 4 because that is how long the grid was down after a hurricane when I was building my house. Only basic circuits were included in my battery backup system and that worked fine until the hurricane with a 5 week outage! I do sometimes see 5 or even 6 dreary days in a row, but that is rare. Think about how many days of reserve you need for your location. For our purposes, here, we’ll calculate for 4 days.
Back in Part 2, we estimated that Will uses around 3000kilowatt-hours (kwh) a month. He’s going to need a 48 volt system, for sure. There is equipment with higher voltages, but it is rare. 48 volts will keep the amperage at modest levels.
OK, 3000kwh per month divided by 30 days in a month gives us 100kwh of power per day, or 400kwh for our 4 day reserve. Divide 400,000 watt-hours (remember, those were KILO watts) by 48v and you get 8333.33 amp hours of battery. See that huge battery at the top of the page? I think that one is 3000 ah. If you haven’t had an OMG moment, yet, consider it really hurts a battery’s lifespan if you drain it down below 50%. So we double it and round it up to 17,000 ah. OMG!
Don’t panic, yet. That 3000ah battery up top belongs to a fellow named Daryl. Daryl has a chain hoist and a gantry to get it tucked into the house and a forklift to move it outside. Daryl is kind of an exception with the equipment he has around the house.
You can buy 2 volt cells with lots of amp-hours that one person with a hand truck can move around. There are also modular racking systems. It is going to take some space and I’m not talking along the back wall of a typical garage, unless you leave the car outside. No, this is not one of those dinky little Tesla Powerwall toys.
There are many choices in battery types. We hear a lot about Lithium these days. They are probably the most expensive option, but they are a lot lighter and you can discharge them deeper without hurting them, so you don’t have to have quite such a large battery. On the other hand, they require a battery management system because running the battery down too far JUST ONCE can ruin it. The best thing is they are sealed and require no maintenance.
Pocket plate Nickel Cadmium, or NiCad, is another expensive option, but these batteries are hard to break. Unlike the NiCads we used to see in power tools, these don’t lose capacity owing to “memory effect.”
Nickel-Iron Edison batteries were so good they quit making them! There are 100 year old batteries still working. The only maintenance is to add water and maybe wash them out every few decades. You can run them completely down and ignore them for years and they’ll come right back to life. They were still made in eastern Europe and China and are now back in USA production. I have been told they have a higher self-discharge rate than other batteries, but have never seen it in a spec sheet. This is as close as you’ll probably get to a forever battery. Pricing is along the lines of Lithium.
Lead-acid batteries are most common. They come in both sealed and open varieties. Flooded, or open, batteries are fairly tolerant of abuse, but require regular service in the form of adding distilled water and neutralizing acid mist. They need good ventilation as they produce hydrogen gas. They come in relatively small and cheap units in the form of golf car batteries or large and rugged industrial cells, as you see in the photo of the red Rolls battery, above. These batteries have thick plates and large electrolyte reservoirs for long life.
Sealed batteries do not normally require any service and can have a very long life. They can be damaged by charging them too hard, though. Make sure to use the appropriate setting on the charge controller.
Regardless of battery type, in a system this large it is possible to have a charge rate that can damage the battery bank. If multiple charge controllers are needed, it may be best to use a controller family that can be linked together to coordinate the charging. I don’t have that with my 4 charge controllers, three different models, but can set the parameters differently on each one to allow for a more modest charge rate.
Here is another consideration of going off grid. You have to have a certain amount of kilowatts coming in to meet your living requirements, but you have to have a battery that can handle all of those amps and watts coming in.
Let’s say we have panels that can put out 200 amps and one string of the Sun230 batteries. 200 amps into a 230 amp battery is charging at almost a charge rate of C1. They are great batteries in their size class, but at C1, they’d melt. Quickly. These batteries are probably best charged at C10 or C20, or a whole lot less than 200 amps. 8 or 10 strings of these batteries would take the charge just fine, but you really should limit the number of batteries strings (groups) because minute differences can cause them to fight each other.
200 amps going into Daryl’s 3000ah Bull Dog battery would be fine. Will’s system is going to make a bit more than 200 amps, so there we are back to another reason to have a humongous battery.
But maybe it doesn’t have to be quite that big. If you keep your grid connection and use a hybrid inverter, you can set it to provide the power when the batteries have it available and automatically switch over to grid power when they don’t. With a relatively small battery, you could run around the clock in good weather, with low a/c demand and pull from the grid if you have one of those long dreary periods. Will has another ace in the hole I’ve not mentioned. He has a natural gas whole-house generator, so the generator could take up the slack in cloudy weather.
Since he has the generator for backup power, there is a way of going grid-interactive without spending as much on the system. That involves the use of Zero-Export Grid Tie. I don’t think that’s the best name for it, but that’s what we have to work with for now. This lets your solar panels reduce your grid power consumption without incurring and Grid Intertie fees that would negate the savings. These can be equipped with batteries, too, to extend the savings into the night. I just commissioned such a setup this morning on the little bit of my house that is on grid, so I can’t yet address what kind of savings you can expect there.
Some lifestyle modification might help on the size of the batteries and other system components. Can you operate the pool pump only during the day with a timer without it turning into a swamp? Better yet, could you just fill in the hole? Snapdragons and Dianthus would be lovely this time of year. Pansies, too, if not exposed to rain and sleet. Will probably likes his pool, but a lot of people do fill them in! It is probably where about $100 of his power is going, too.
Also on the pool, if you have a heater and you have natural gas, I hope that is what you are using. Better yet, solar thermal heat. Super cheap and efficient!
Anyway, I have rambled on a bit long, but you should be able to find some things to consider in there, too.
We can talk about charge controllers to charge that big battery next time.–Neal
Take a good look at the photo. These guys are going to lose space for an entire panel because of a vent pipe poking up through the roof. Why are there vent pipes? Because when you use a sink or any other water source in the house, it needs to be vented to drain properly. The vents stick out the roof because clean water is not the only thing that goes down the drain. You don’t want the aroma of your septic tank or sewer line in your attic.
Why is it on the roof? Plumbers put a vent for every drain cluster because it is easier and cheaper for them. I don’t like holes in my roof, so I went to the expense and effort of plumbing them all into one vent. My roofer dude tells be there is a gadget available so you don’t have to have ANY vents poking through the roof. It is basically a check valve that lets air into the line when you pull the plug on the bathtub, but does not let the stinky fumes out. These guys (or the homeowner) could have eliminated that vent, gaining a few more watts and a better looking installation.
Next, put your modules up in order. That saves having to walk on the glass. Glass is slippery, (more so when dusty) which is a danger to the installer. Most panels are not made to support a lot of weight, either. At least where this guy’s foot is, the frame is taking most of the load. Oh, and a suction cup would have made it easier to get the bottom end of that module brought up even without risking a finger.
Finally, why not give the panels a wipe down before installing them? Rain won’t necessarily wash all of that off.
Otherwise, things look pretty good. Two rows, mounting on good hardware and walkways for future access.
Just a quick tip coming from experience. I was out in the Solar Shed, today, pulling wire to add a couple more panels to my Non-Export Grid Tie experiment. I’ve been running 1200 watts, being shared by two GT inverters. Now it is 1800 watts. Soon, it’ll be 2400 and live on the grid instead of in the lab.
I have the giant spool up on a rack on the back of one of my electric trucks so I can point myself in the right direction and run with the end of the wire. Apparently I have been doing that a lot, because I am starting to see the core. I checked the number on the side of the spool with the number on the wire and, yep, getting close to 1000 feet that’ve been used. The Shed is 80′ long, now, so some of the wire pulls are pretty lengthy. I had hoped that spool would last me through the next addition to the Solar Shed, but looks like I’ll have to buy another spool. Tip: write on the side of the spool the first footage number you find on the wire so you can keep up with how much you’ve used and make sure your vendor is straight with you.
I rummaged in my parts drawer and found MC4 splitters and enough connectors for the job, but not enough for the next and final step to a total of 8 modules on this project. Then it dawns on me, using the splitters I’ll have too much current on that #10 wire, so that means perhaps another 80′ of wire. AND, naturally, I didn’t have enough pins for the connectors. As I progress with the Shed, things are gradually getting more organized, but there was difficulty finding the sack of MC4 connectors I knew I had recently (sometime this year) bought. I finally found them and was in business. Hooray! When I finished, I put them in the new parts bin, an old lateral file from Goodwill. Lateral file cabinets are showing up everywhere as businesses put everything in digital form in the “cloud”. A friend paid $15 for one, I think, and they told him they had a bunch more he could just have at no cost. They are wonderful for storing parts. I have plastic tote bins in mine to separate the parts.
You can, of course, buy pre-made cables, and they’re fine if they come with a kit, but do you really want to stop your project and order stuff every time something turns up a bit short or you make a change? For a bigger system, you’ll also find buying wire and cable in bulk can save a bunch. I’ve bought the big 1000′ spool of solar wire, full 100′ spools of 00 and 0000 cable, sacks full of MC3 and MC4 connectors, and buckets of terminal ends for battery cables. Yeah, it hurts really bad when you buy a big spool of cable, but ultimately, it hurts a lot less than buying by the foot or by the finished cable. Not only that, it gives you the resources to make changes or additions when you are ready to do so and not when the postman or UPS dude brings your small order two weeks later.
It’s also good to have some spare hardware when Stan-the-Hermit comes buy looking for some stuff for his system. He may be too late to get into THIS spool of wire.
We now know a bit more about Will’s roof, his power consumption and what he wants to do. Let’s get started…on some Texas-sized solar power.
I’ve been in contact with Will and he supplied some more information. If you read Part 1, you know he wants to go with solar power, but that leaves a lot out. We now know that he has a big house, 3700 sq. ft., and pool. He also has a Texas-sized power bill and wants to go off grid before he retires.
Let’s start with his power bill, a bit over $300. We don’t know the kilowatt-hours he uses, but we can come pretty close from the bill. “A bit over” can cover the base fee, leaving $300 even. Another Texan, Donald, tells me his power costs a dime per KWH. So .10 into $300 gives us 3000 KWH.
That’s a bit more than most folks, but I am told a pool can take up $100 worth of power. I don’t know much about pools, but I am aware there is a pump and often a heater. I wonder if the pump could be put on a timer to only run during the day when the sun is working? I don’t know how Will is heating the pool. I know he has natural gas. That’s the way to go OR use a solar thermal heater. That is relatively inexpensive and there is no fuel cost.
Regardless, 3000KWH divided by 30 days in a month, gives you 100KWH of power per day of consumption, which is an easy number to use.
We don’t know his average hours of insolation (not inSUlation), but he can look that up on numerous websites, but lets go with 5 hours, as he is at a similar latitude to my place. Divide your daily 100KWH by your presumed 5 hours of full effective sunlight and that means you need 20KW of solar.
When we say 5 hours of insolation, you know you’ll be getting a little bit at 7am, a lot at noon, and a little at 5pm. That’s 10 hours of some amount of sunlight and factors in the average and some cloud time. It isn’t perfect, but you have to start somewhere!
If you find a deal on 250 watt panels, divide 250 into 20,000 (remember, it was 20 KILO, or thousand watts) and that comes out to be a whole bunch…80 panels. Oh my, that’s gonna take a lot of roof. Let’s run that again with some of the newer, more efficient panels. I have some 300 watt panels that are the same width as a 250 and maybe and inch or two shorter. 300 into 20,000 gives us a need for 67 panels. That’s a lot less, but still a bunch. 400 watt panels are becoming more common. I saw where one company just announced a 440 watt panel, but I doubt you can buy them yet. Let’s try 400 into 20,000 and you get a more manageable 50 panels. However, these are going to be bigger panels.
We’re now at the point where an old boss of mine said we’d “play with paper dolls.” This was before computer CAD programs. We’d take a piece of graph paper and draw out the roof, in this case, to some convenient scale. Next, using the same scale, we’d cut out 50, or 67, or 80 paper panels to scale (starting out in strips) and then start shuffling the paper panels around on the paper roof to see IF they’d all fit and HOW’d they best fit. A good scheme is to butt together two rows, skinny sides together, then leave some walk space, unless you want people walking around on your panels. If fact, I think the Code now requires that you leave some walking around room. In two row sets you can get at them for troubleshooting or service if you should ever have a weather (hailstones or hurricanes) or electrical issue (lightning, hotspots, hungry squirrels). If you use CAD at work, then you are already prepared to make a roof model on your lunch hour. There are even free CAD programs that you can download and learn to use at home. We didn’t have CAD when I went to engineering school, so I am comfortable with a pencil and a bit of graph paper, but I designed a bunch of computer stuff using CAD, too. Your choice.
Looking at a sketch of Will’s roof, it seems to be 69′ long and facing south. You couldn’t ask for a better start! Let’s see, those 300 watt panels are a meter wide, let’s call it 40 inches. 69′ is 828″. 828 divided by 40 is about 20 panels wide, not counting a useful walkway. One thing that concerns me is a dashed line. I’m thinking that represents something like we have at Mom’s house. There, you have one level of roof over the living area, then it steps down 2 feet across the double carport and the garage. If there is a stepdown, depending which way it goes, there’s going to be some shading going on early morning or late afternoon. You’d best leave some panels out to avoid the shade. Shading a panel can do more than just reduce your power. We won’t talk about that right now, but it isn’t a good thing. Let’s assume a shady area and leave a panel or two out for a walkaround.
Can we do more rows, because it looks like we’re short? Yup, he has 24 feet of slope. Let’s just say a solar module is 6′ tall. Most aren’t but that’ll give us some margin. 3 rows is then 18′, leaving 6 feet to divvy up for walkways. Let’s just say we took out two panels for our presumed shade, leaving 18 to the row. Three rows make room for 54 panels. Not enough for 300 watt panels, so we might want to consider the 400 watt class. Download a spec sheet to make your paper dolls, either the literal kind or the virtual ones.
Oh, but no worry. Aside from that long stretch of 24 feet, he has an extension in the middle. It is 16 x 24, which could give him maybe 3 more rows of 4 panels, bringing the total to 66. We have this licked!
Ok, understand that solar panels are rated for certain standards for conditions. Unless they are on a mountain top, free of haze and running cool, they are not going to put out full rated power. Also, understand that things may change and you’ll want more power. Think ahead and leave yourself some margin.
What I am thinking here is to fill every one of those rows up with 335 watt panels, assuming the scenario I have described will play out. Where’d we leave off? About 66 panels? 335 watt panels are cheap and plentiful and 66 of them will make (ideally) 22KW. Multiply by 5 and we have 110KWH, giving us a 10% margin. Hey, if you can get more up there, go for it. Trust me, except when it comes time to write the purchase check, you won’t complain about having more than enough power.
OK, we’ll leave Will to check the numbers for how many he can get up there without shading and check on walkway requirements in the local code. I think this will work.
Next time we’ll talk about something else that is very important: the big, ginormous battery. Will’s going to need one.
The Texas-sized power system in the photo at the top of the page comes from Daryl T.
UPDATE: Wouldn’t you know it, I say 335 watt panels are cheap and plentiful and then find John is out of them! He has plenty of 320 watt panels, but I think 66 of them will cut it too close. The big surprise is the deal on some of the newfangled half-cut 385 watt panels. They will give lots of margin and cost less than the 320w modules! Available in pallets, only, but Will is going to need pallets. Call Sun Electronics for a spec sheet to get the size.
Actually, Will has several questions, but they all boil down to “how do I get started?”
” I am looking into installing solar panels on my roof. I have a straight gable roof that the back slope faces South. I have a 200 amp breaker box and would like to keep that amount of power when I go solar. Looking at solar panels, they come in different amounts of watts per panel. How many watts do I need to support my existing amount of power?”
I have been looking for just the right topic on getting started and Will handed it to me by email. I’m not going to get terribly detailed in this installment. We’ll hit the highlights, this time, and fine tune the details, later.
He wants to go solar. Yay! But how? He does not specify, but it sounds like he wants to go off grid. Again, how? Grid-tie? Hybrid? Off-grid? It can make a big difference in costs and your circumstances may change your options. Pure grid-tie used to be the best bang for the buck, but that has changed in some areas. It can ADD to your power bill! (I am testing a workaround for that.) Do your research and find out what the deal is with YOUR power provider. The major downside is that if the power goes off, it goes off. All those panels on the roof don’t help.
A hybrid system can do grid -tie and give you backup power when the lines are down. Sound good California? OR a hybrid system can interact with grid power, reducing the bill, and NO extra charges for grid-tie. It is almost like being off grid, but the grid is your backup power. In an emergency, you can be off-grid by cutting back on your loads.
Of course, there’s off-grid, too. This is going to cost you the most and may inconvenience you a bit. You don’t have any backup from the grid. If anything goes wrong you run the backup generator or you sit in the dark until parts arrive.
Those are the choices that jump right out. As I said, we’ll dig deeper, later.
“ I am looking into installing solar panels on my roof,” he says. In many cases that is pretty much the only choice. Rejoice, Will, that your roof faces south. It may not be at the perfect angle for your location, but PLEASE don’t let the installers go with some whacko angle! Keep it low and subtle.
There are questions that must be asked, though. Are you wanting to use conventional panels or some of these solar shingles, like Mr. Musk is promoting? Do you have a homeowner’s association that will pitch a fit over panels? Is your roof strong enough? (I have over a ton of panels on the roof of the Solar Shed.) Are you going to have to hire an engineer to prove it? Does your roof have a bunch of pokies sticking out all over? Are there trees shadowing it? What kind of condition is the roof in?
Most important, maybe, is the condition of your roof. An old roof could not stand the trauma of a bunch of guys stomping around stringing wires and bolting down panels. I’d need to spend 12 grand on a new roof before considering putting solar panels up there. Is your roof in good condition, Will?
“I have a 200 amp breaker box and would like to keep that amount of power when I go solar.” Hold on, there, Will. You have a 200 amp breaker box because the code required it, not because you need it. 200a x 240v= 48,000 watts. I can’t imagine you using anywhere near that much power, even if you were trying. My first house wasn’t big, but everything was electric except the heat. It was an older, post-WW2 house with 60 amp service and I never blew a fuse. After one particularly nasty hurricane at my present house, I fed my generator in through a 30 amp breaker and got by ok if using the loads on a staggered basis. For a real world example, Tom lives in a 25 year old all-electric house, full of computers and home entertainment stuff, central air, served by two 8kw inverters. He could get by on 8kw if staggering loads. 12kw worked fine. The pair of 8kw inverters allows him to get by if one breaks. 16kw/240v is 67 amps, about the same as my old house! What I am saying is, you don’t need 200 amps of solar-generated AC.
“How many watts do I need to support my existing amount of power? “ Good question. First of all, are you currently cutting back on comfort to save a little on the power bill? First thing I did when I got the a/c ported to solar was lower the thermostat last summer! Consider adding a little for a decadence factor! If going off grid, I’m pretty confident that 10 or 16kw of inverter will be plenty. There’s more to it than that, though.
OK, dig around in the drawer and find all your power bills for the past year. Find the biggest one. In KWH. Divide by 30 to make it a month. Where you live and how your house is built will make a tremendous difference, but let’s just call it 1000kwh for the month. That’s over 33kwh per day. Round it up to 34, because you can’t have too much and you don’t want too little. Do a little internet search for solar insolation (how much you get) for your area. Typically, that’s about 5 hours a day at more or less full power at my Gulf Coast latitude. So 34 (make it 35 for easy math and an extra margin) / 5 hours =7kw of solar power. That’s around 21 panels, give or take the model. Oh, it doesn’t matter if you use 250 watt panels or 300 or 400watt panels, if they all add up to what you need, but they should all be the same in most cases. With limited roof space, you might find the newer, more efficient 400+ watt panels may be necessary to get enough power in the available roof space. Yeah, you are going to have to do some measuring and you’ll have to leave some walkway space unless you want someone walking around on that glass! Sizes of various modules can be found on data sheets at Sunelec.com and other web sources. Call John’s crew if the spec sheets aren’t posted.
Off grid, you can’t mess around. Traditionally, when solar was really expensive, off-gridders just figured on running the generator some. Today you can probably get by without it, but you need enough solar and enough battery. Tom’s system has 10kw of solar and maybe 400amp-hours of battery. His operates in a hybrid, interactive mode, so solar provides all the power on a sunny day, into the early evening. It cuts out as the a/c runs all night or on cloudy days. He has plenty of solar and not enough battery. Batteries are expensive! My current situation has part of the house on grid and part on solar. I have maybe 14kw of panels presently active and 800+ amp hours of battery. In good weather I could probably run the whole house with a bigger inverter. As it is, though, if I get 3 or 4 days of gloom, there’s a good chance I will switch all of the house over to the grid to save the batteries from running low enough to damage them.
I guess what I am telling you is, it’s complicated. There is a delicate balance between the amount of solar power you have coming in and the amount of storage you have to keep it. If your batteries get charged by noon, but sometimes get wimpy in cloudy weather, then you don’t have enough battery!
A more practical answer might be to figure out if your roof will hold the number of panels you calculated. If so, you have lots of options. Heck, fill it up! If not, go with Zero Export (we’ll talk about that later) grid-tie and save some bucks. You can always change things later.
Tropical Storms in the Gulf, tornadoes in Alabama and lots of rain.
That’s not a time when you’d normally think solar power, except how little the panels are putting out. It IS a good time to hole up with a small project.
In the last post, I mentioned the Tiny Watts group and their tiny projects. And I mentioned that Solar George had given me an idea. I had a couple of small solar panels from garden lights. I found them in the dumpster at a house I was rebuilding, so free solar is always good. I think I may have another from a light I bought that didn’t last long. Anyway, these two put out about 6 volts in good sun. A load will drag them down to 5v, so that sounds good. I would guess they are in the 2 watt neighborhood, so that sounds tiny. Next, I scratched up a couple of micro-USB cords and cut off the big ends, leaving a few inches with which to work. I buy those by the sackful, because they get lost or messed up. No telling how many are stuck in the seats of my truck.
Strip back the wires on the big end of the USB cord and plug into a USB charging source to determine what wire does what. USB has 2 data wires and a shield in addition to the power wires. I guess right that red and black were the positive and negative, but don’t assume yours is the same as mine. Check the polarity. Toss the big end and strip back the insulation of the small end a bit. Leave enough room to get some shrink tube or tape on the joints when the soldering is done.
Cut off the connector on the panel and figure which wire does what. In my example, blue was negative and brown was positive. Your mileage may vary. Red to brown, black and blue is the order of the day.
Warm up the soldering iron and find the solder, shrink tube and/or tape. I slipped on small shrink tube over each conductor of one end and then a bigger, longer piece to cover the entire joint. I didn’t have any heat sealing marine shrink tube or I’d have used it to seal out water and make a better physical grip. Wrap and solder the joints, slip over the shrink tube and heat shrink it with the solder iron, a torch or a heat gun.
I plugged it into my Motorola flip phone, the only kind that works where I live, and it told me I was using an unauthorized charger. It is fussy that way. No problem on my LG. I plugged it into my Tomo 18650 battery bank and it went to charging, even with the heavy overcast. I can use the 18650 cells, recycled from the many laptops I have outlived, in my flashlight or charge two phones at once and I can charge them at night. My Motorola gets along with it. Since the battery bank has two USB ports, you can even plug your iPhone cord in. The microUSB with the solar panel is more useful, I think, because it plugs into more things and you may be able to still end up charging the iPhone.
Yes, I know you can buy a battery bank kit with built in solar charger and even an LED light for just a few bucks on eBay, and I may even get one, but this project was recycling some good junk box stuff and making something useful. The long wire on this version will let me stick the panel outside and keep the stuff getting charged inside out of the rain. Order one of the kits and build your own if you don’t have stuff in your junk box. Good fun on a rainy day.
Warning: Different phones react differently, so keep an eye on it. This is unregulated, so don’t wander off, leaving the phone plugged in to overcharge or damage the phone. A 12v panel wired to one of those cheap USB cigarette lighter adapters may be safer.
Just a few notes on solar in the news. Click in the parentheses for the links, since I can’t seem to make them show up in some browsers.
A really biased (headline) blames California power outages on climate change. The actual cause of PG&E outages is PG&E pulling the plug when it gets breezy! Proper powerline maintenance, line stabilizers and right-of-way maintenance to reduce fuel would go a long way to prevent fires from powerline sources. Better forest management wouldn’t hurt, either. Of course, they famously turned off the power to millions and there were fires, anyway. Today it was reported that they turned the power back on and a line fell from one of their newer towers (47 years old), starting another fire. The positive thing coming out is people and businesses are scrambling to find solar and battery solutions to keep their power on and their businesses open. They could learn a lot from John’s customers in Haiti.
Next up is recycling. Solar power has changed so fast that facilities are changing out the panels they installed a few years ago, going for the higher output of today’s panels in the footprint of the old ones. That leaves truckloads of perfectly good panels looking for a new home. That’s just one way John brings cheap panels to Sun Electronics customers. That’s why you can buy a 70 watt panel, single piece, for $12, or as low as $7 in quantity. Or a 300-ish watt panel for a hundred. Another source is insurance claims. It seems that if a half dozen panels get popped in a hailstorm, they’ll go ahead and replace the other hundred thousand, just so they’ll all match. More bargains. You and I putting those surplus panels to work is the best form of recycling. Then there are those that are well and truly smashed. As John has pointed out in his blog, there’s no good way of recycling them, yet. The growing pile is prompting lots of new research on ( recycling and reclaiming. ) Of course, there are new surplus modules, too. Companies go bankrupt or get into some sort of bind and there’s another container load of them.
Finally, something fun. Are you wanting to try your hand at solar power? Is your kid looking for a science fair project. Check out the American Solar Energy Society’s ( Tiny Watts) program. Program members build their tiny watt phone chargers, battery chargers, portable lights and all sorts of things. I guess the solar toys John used to have would qualify. I put a solar powered spider on the table in Mom’s sun porch and it would drive her cat nuts! Inspired by Solar George, down in the Keys, I found a couple of 6″ panels from a yard light and will turn them into USB chargers. I figure you can use them directly to charge a phone, but I will go one better and let it charge one of those USB battery boxes. The battery box, using 18650 cells reclaimed from my pile of old laptops, can then charge two phones any time of the day or night. What kind of Tiny Watt project can you make? Check the link, above, for ideas.
When installing a new power system or doing a little troubleshooting, an appropriate meter can be just the thing to make the job easier. For example, with the analog voltmeter and the digital ammeter, we were able to determine that the panel above was a little low on output. What could possibly be wrong?
There are analog meters, which you don’t see much, anymore, and the digital meters which seem to be in favor these days. There is one of each in the photo above. Below, we’ll zoom in on the analog meter for a quick briefing. It isn’t that hard, especially since they have numbers regularly spaced along the dial. I’ve recently endeavored to teach an eleven year old to tell time on an analog watch. The Timex, having 12 hours delineated was not such a problem, but a PRC200 has only 3 numbers and a Submariner hasn’t any at all. Try to explain how using a watch with no numbers is easier than looking at her cell phone! But I digress. Speaking of watches, take ’em off, along with rings or other hand jewelry. Put on some gloves for poking around in higher voltage circuits. 24v can give you a tingle if you are sweaty.
This meter is pretty easy. There are 10 little chops between the 20 and the 30, so each chop is a volt. The needle is four chops over, so the voltage is 24.0. If it were 1/3 of a notch to the right, then you’d have 24.33 volts. A really high precision meter would have a mirrored scale so you can line up the needle with the reflection to make sure you aren’t reading high or low by looking from an angle. I grew up on this stuff, before there were digital meters, so it comes naturally to me. After dealing with the youngster and the watch, I’ll understand if it is strange to a person under 40.
Above are some digital meters, typical of what you might use. It seems you can spend as little or as much as you like and get a useful meter. The red one you can sometimes find free, with coupon, at a certain popular tool store. As long as you remember to turn it off when not using it and don’t pull too hard on the leads, it is fine. And free. The one in the middle actually includes a digital oscilloscope! It also has better leads and will turn itself off. The one on the left is often called a clamp meter, as you pull that red trigger to open its mouth, clamp it around a wire and then read the amount of current (amps) going through the wire. Some clamp meters only work with AC, as indicated by the squiggle by the A. These are all referred to as multimeters because they have multiple uses, unlike the analog example, which only measures between 0-50 volts DC. Let’s take a closer look at the clamp meter.
As you can tell, this particular meter lives near the bench saw. A little sawdust never hurts, but how embarrassing! Normally the arrow on the knob is pointed at the OFF to save battery. It is presently set for a range up to 750 volts AC or vac. The squiggle under the V means alternating current. The 1000V range below it has a straight solid line and a straight dashed line, indicating DC. 750 and 1000 are rather large voltages, so you will find a meter like this is not the best thing for checking batteries with any accuracy. This is best for the big voltages, like the 240vac output of your inverter or a 600 volt string input to a grid-tie inverter.
The lower left scales are for resistance. The 200 position with the funny symbol indicates that you can measure the resistance of a cable up to 200 ohms (which would be terrible) or it will beep if you have a dead short, like when testing a good cable or fuse.
Over in the lower right corner is where you check your amps with the clamp. See the A (for amps). If I clamp onto one of the big wires on my air conditioner I might see around 11 amps. You can multiply the VOLTS times the AMPS to figure WATTS. Of course, if you are drawing too many watts your circuit breaker will let you know, but by measuring when everything is right, you can make sure everything is sized properly for the job at hand. One last little feature in the upper right corner of the photo is the HOLD button. If you have to put the meter into a position where you can’t read it to clamp onto a wire, you can press the red button to hold the display until you can pull it back to read it.
The meter in the middle has a lot more precision and it has automatic ranging, so you just set it to AC or DC or whatever and it figures out if you are measuring a volt, 100v or even more and displays it in the proper context. It even has a built in frequency counter (Hz) that can tell you if your inverter is putting out 50Hz or 60Hz. The inverter can be set wrong and it can make a difference! The oscilloscope function is not great, but it can tell you if a power output is a sinewave or a modified sine wave.
The main reason I wanted to show you this one, though, is the sockets where the meter leads plug in. This meter is pretty typical in that respect. The black lead always lives in the COM hole and the red normally lives in the V socket. To measure current, you set the dial to the appropriate position and move the red lead to the 10 amp or ma position. Don’t mess this up! When set up for measuring current, you usually use the 10 amp scale for solar and you take the cable off the battery. If you pull the positive cable off the battery, put the red lead on the positive (+) battery terminal and the black lead to the wire you took off the battery. You can now measure the current going through the circuit. Note that the meter at the top of the page is set up for current and is reading nearly an amp of current.
You can use this mode to test a solar panel by setting the 10amp mode and poking the probes into the connectors on the solar panel. If the labels on the back says you should have a short circuit current of 7.4 amps, then that is about what you should expect if you check the current of a CLEAN module pointed straight at the sun. In fact, checking both the current AND the voltage is a good idea.
Here’s what you have to watch out for, though. When you are through checking amps, DON’T just turn the meter off and stuff it back into the tool box. You usually test voltage, or most folks do. If it is set up for AMPS and you put the leads across the battery you are going to be very disappointed with yourself, because at the very least you will blow a fuse in there. You might also burn the leads or a bit of circuit board. Not fun.
Let’s see if there is anything interesting about the free red meter.
You can see that this one is not auto-ranging. Like the clamp meter, the AC range is pretty high, but that’s ok. There are lots of choices on the DC range. If you have a 12v system, select 20, because the battery may get up to 15 when charging. For a 24 or 48v system use the 200v range. This one does not have a beeper in it, so select the 200 resistance setting or maybe the pointy diode symbol to check a fuse. Like the other meter, you move the red lead to the 10ADC socket to test real amps and don’t forget to put it back when finished. You probably won’t need any of the rest of it. If you do, you already know how to use the meter, I suspect. DON’T leave a cheap meter on when not in use. Of course it runs down the battery, but on some it will also burn out the display owing to electrolysis. Who knew?
Here is a handy meter to have if you have batteries. (above) Yeah, it is analog, but I like analog. With one of these, you turn the big knob counterclockwise until it feels loose. This is primarily a 12 volt tester, but if you are using 6 or 8v batteries you can either interpolate or put the 6v batteries in pairs for the test. Come to think of it, you’ll just cause trouble if you don’t keep it down to 6 or 8 volts. We’ll start off with a marine deep cycle battery as a 12 volt example and just scale everything down for the lower voltage batteries. If it is your meter, you can make your 6v marks with a Sharpy. Disconnect the batteries from the charging and load circuits and clamp the red clamp on the positive terminal and the black onto the negative. Watch the terminals when you increase the current. A bad connection can get real hot in a hurry with hundreds of amps involved!
If it is a fresh 12v battery you should get a bit over 12 volts, maybe even over 13. Anywhere in that middle green zone on the right is fine. Nothing should happen on the left meter until you crank the knob clockwise. You will tighten it until the needle falls down into that area where the red and green show a stair step. Guess the temperature and choose your notch. This is really loading the battery. To get a good estimate of capacity, you now look over at the left meter.
This unit is really set up for testing something the size of a car battery, so two T105 or Sun230 or GC2 batteries in series are going to slam the needle off scale to the right because they should indicate over 200 amp-hours and the scale only goes to 160. If the needle slams to the left you hooked your cables up backwards and you just broke something.
Anyway, for a trolling battery, you should see something on the order of 80-120 on the green amp-hour scale and you should see it hold fairly steady for about 15 seconds or until the timer beeps. If testing a 6 volt battery, turn the knob until the VOLTS needle is in the 4-5 range, depending on temperature and roughly double what you see on the left meter. The real key here is that the amps should drop rather slowly on a good battery and they will go quickly on a bad one or one that is badly sulfated. If you ignore the timer and leave it connected the tester will begin to smell bad and that can’t be good. It never is. If testing a number of batteries, take your time and let the giant resistor cool down a bit.
That may sound complex or tedious, but really it isn’t once you’ve tested a few batteries. Read the manual for all of these meters for the fine points of use and care.
Quick tips on what to do with your meter? Check your solar panels you just got in or if your system is acting up. Specs for volts and amps should be on a label on the back of the panel. If not, you can Google just about any panel data sheet.
Check a fuse, circuit breaker, cable or switch for continuity.
Check the output voltage and current of your inverter or charge controllers. Most have built-in metering to some degree, these days, but sometimes a second opinion can help.
Test a battery.
Make sure the cables are the right polarity before connecting panels or batteries to other expensive stuff!
Well that should be enough to get you started. Have fun with your new meter. –Neal
Some folks have big systems and some have small. A small solar power system is pretty easy to wring out if there is a problem. Use your multimeter (You DO have a multimeter, don’t you???) to tell if you have volts getting to your charge controller, or if you have it up to that fuse that blew, but not beyond. A bigger system can be a little harder to keep up with.
My system has HUNDREDS of panels, because they are small, 34 watt modules. They are organized in 4 medium voltage strings to each charge controller, via cutout switches and fuses for shutdown, isolation and circuit protection. This allows me to quickly troubleshoot if something doesn’t look quite right.
Let me remind you right here, that while I do have some shiny new panels, I have a lot of salvaged panels that are not exactly prime stuff. I have had a problem with a new panel, but mostly it has to do with the older stuff. A lot of times you can troubleshoot without even breaking out the multimeter! Read on.
Real life example from this week: I’m out in the Solar Shed to start putting up the ceiling in the control room. It is 111 degrees in there. ACTUAL degrees, not the fake “feels like” kind. The purpose of the ceiling is to keep some of that 150 degree heat from the back of the roof modules from getting into the control room. It works, by the way. Anyway, I get one sheet of plywood on the rafters and, to avoid death by heatstroke, I take a break. Looking at the meters on the charge controllers I see that something is off on Bank 4. Pull a switch and it is narrowed to String 4A or 4B. Pull a fuse and, voila, I have determined that 4B has bit the dust without breaking out the multimeter. Swap the two fuses and same result, so it isn’t the fuse. This is not a surprise.
The fuses, switches breakers, etc., are all labelled so as to associate which watts go through what equipment. Now where is string 4B? I look up through the ceiling that isn’t there yet and can see my code marks on the fat white solar power cables. 4 dashes and 2 dots. 4B. Top two rows on the end. C and D use normal panels outside until the next section of the Solar Shed is built this winter. You know, when it isn’t 111 degrees in there.
I didn’t take a thermometer up top, but I am pretty sure it was not any cooler. There are about 21 panels to a string and I know that these are some of the iffyest of all the solar shingles. I can take a meter and start unplugging, testing and replugging, or I can start by just looking. Note: NEVER unplug your MC3, MC4, TYCO, etc. connectors while the circuit is active. You can draw an arc and ruin the connector. Or a finger. Anyway, about 4 panels down from my point of entry, I find what I think I am looking for: a bubble in a jbox. Bubbles form when diodes get hot and die.
Sometimes the diode set can be replaced and sometimes not. Since these are relatively small panels, I have built in a number of spares and just use a jumper cable to work around the bad panel. We’ll talk about repairing modules another day and if I repair that one, it’ll be a cooler day. Anyway, the problem was isolated just by looking.
Here’s an easy one. A big black cat will dramatically reduce solar power output. Fortunately, panels are a little too hot for cats in the middle of the day. My solar boating projects have panels mounted flat whether on the boats or just testing equipment.
Here’s a more serious example. This is called a hotpot. Quite often, it gets hot enough to break the glass. I caught this early. You can see that two of the four main wires through that cell are burnt open. That puts a lot of work on the remaining two. Output is reduced and it gets real hot, about 50 degrees hotter than the rest of the surface. When we talk about fixing things we’ll come back to this one.
If this panel had been mounted above eye level, you might not have seen that burn, unless you looked up and saw the back side of the panel. It got right toasty on the backside as well.
Maybe after my first example you’d be tempted to glimpse at the junction box or jbox, looking for diode troubles. Yup, this one had it all. Bubbles are not our friends.
Keep an eye out for an Infra Red thermometer on sale at America’s Favorite Chinese Tool Store. They are not expensive and are a very handy troubleshooting aid. After coming back to the Solar Shed after a break, I smelled something funny. Eventually I followed the nose inside the control room where the scent was the strongest. I waved the IR thermometer around and discovered that the electric fan that had been running out there was no longer running and was humming at 277 degrees F, while emitting its faint aroma. Better a 1940’s vintage table fan than my inverter! The IR thermometer can help you spot a piece of equipment with a bad fan if you know what the normal operating temperature range is. If you don’t know, but see that one piece of equipment is hotter than the rest, that’s a clue. The IR thermometer will tell you without risking blistering your finger tips!
Ok, here’s an easy pitch.
The front glass is busted. Solar glass does not “sorta” bust or even “kinda ” bust. When it goes, it goes. Hailstones, rocks and young thugs with size 12 boots will do this. In this particular example, somebody didn’t remove the screws before stacking them on a pallet. This is really not as bad as it looks. In addition to the backsheet, there is a clear sheet between the glass and the cells and there is a chance that everything is still perfectly sealed. If you still have good output, you can use a silicone coating made just for this issue, called Q-Sil. It is reportedly good stuff, but not cheap. DO NOT use the AS-SEEN-ON-TV instant spray-on sealer as it turns opaque white in a few weeks. Been there, done that.
DO NOT mix panels with the stylish craqueleur with panels with clear glass in a series string as there might be reduced output, even leading to the dreaded hot spots. I would not recommend them in a high-voltage string, either, though that may not be a worry. There are always lots of little single panel projects that are a good match for these. Best of all, if it wasn’t YOUR panel that got broken, somebody else might just give it to you. John came across 3000 250 watt panels the other day that had been hit by hailstones. The price was super cheap, but he’d have to ship them cross country. Would you buy broken PV modules? If so, John’ll give you a deal on 3000 of them. Plus postage.
Ok, this last one is pretty obvious.
It actually still kind of works a little bit, even though the bullet holes have let out most of the magic smoke that makes electronic stuff work, but merely by looking at it you have determined that something just isn’t quite right.
That’s the trick. Know what things are supposed to look like and the trouble will sometimes just jump right out and let you know.
By the way, that Silfab 335 was the only one of 10 that gave any trouble. I have no clue as to why it did that. Anyway, I bought those from Sun Electronics and when I sent those pictures you see above I was given a prompt refund. Some outfits would want you to return it and pay all the shipping, but I quickly got a refund check in the mail. John is real good about backing his products.
Maybe next time we’ll talk about testing with a meter for some of the trickier stuff. –Neal
My first solar project was to put 4 tiny 6 volt solar panels on the top of the instrument panel of my old Piper TriPacer. The panels were little more than experimenter toys made from solar cell scraps in a plastic frame. 40 years ago you took what you could get in solar. Old airplanes have tiny batteries, crappy starters and high displacement engines. Add in flying them only on the weekends and you can end up having to change out the very expensive tiny battery every year, or starting it the old fashion way by flinging the prop by hand and hoping the plane doesn’t run off without you. That installation involved about 1/8 amp of current, if that much, and until the panels shook apart I didn’t have to buy a new battery or hand start the plane. Just a little trickle charge is all it takes to keep a vehicle battery ready to go and extend its life.
Those panels probably cost $80/watt way back then. Adding in a diode to prevent back flow, a fuse to make the feds happy and a Form 337 to make it legal and I was in business. If the plane had had a cigarette lighter plug I could have avoided the paperwork by making it portable.
Since then, panels have gotten a bit cheaper, but the installation is pretty much the same, as is the benefit. Nowadays, though, I usually do it on a tractor or help a neighbor put a solar charger on a 4-wheeler, tractor or motor home. Baby Brother has an old pickup he doesn’t use much, but it always starts, thanks to a pair of 5 watt modules mounted on a frame in the truck bed. Using a small module, like 5-10 watts, you don’t really need a charge controller, as long as you are using a so-called 12 volt panel. FYI, a 12 volt panel will usually put out about 18-20 volts without a load. If you want to mount a 300 watt, 24 volt panel on your truck’s tonneau cover, then you definitely will need a charge controller, with MPPT to get the voltages compatible. Sun Electronics often has some of these small panels for small projects.
After my airplane phase, there came a tractor phase and a lot of them followed me home. That’s a lot of tires and batteries to keep up with if you want to keep them going. Some of them go and some of them went. On one of my old Rooskie tractors I put a stainless steel marine panel on the fender. They claimed it was flexible and if you tighten the screws enough it actually bends. And still works! I know the old beast looks pretty rough, but the decade-old battery will start it right up! Yeah, I know the back tires are on backwards. It helps me get out of trouble easier than getting into it.
The installation involves only a surplus panel, some screws and an inline fuse holder. Connections are made directly to the battery, red to + and black to -. A blocking diode is built into the module. My newest tractor, only 21 years old, is about to get a similar mod to keep its 5 year old battery going for a long time.
If you have this setup on the end of the tractor hanging out the back of a shed, you can easily connect an overhead light, using a 12v LED bulb, using a plug or big gator clips. These Belarus tractors came with a socket just for plugging into a light. Very handy.
A little project like this can be a great confidence builder for the solar beginner and produce some immediate benefits, like not having to buy so many batteries or break out the jumper cables as often. Too bad solar can’t fix tires! –Neal
John was just about worn out when I talked to him, yesterday. He’s at the big solar show in Salt Lake City. Sun Electronics does not have a booth, there. He’s there to hobnob and network, catching up with old friends and keeping up with the latest offerings.
All of the panel makers are there, including the Chinese, who are not selling a lot of modules owing to the tariffs. I’m sure each maker is emphasizing that their panels are blacker, less reflective and .001% more efficient than the panels in the next booth! Not to say that all panels are created equal…they aren’t. That’s a good thing because there are special applications. In the next day or so I will write about some renegade panels I have come across and how to use them.
So, there he is, shuffling down the aisles, gawking, trading business cards and peeking in on seminars. They have modules, inverters, batteries and every conceivable gadget and gizmo related to solar and what do you think catches his eye? A racking system.
John recently had the opportunity to buy a small solar farm. Not just the panels, everything. Right down to the last nut and bolt. Even the galvanized iron posts ripped from the ground with balls of concrete around the base. I would love to get ahold of stuff like that, but there is a problem. Shipping. It costs more to ship it than it is worth.
That’s really a shame. Rather than reuse a perfectly good item, it is cheaper for them to sell it as scrap and have it melted down to make something else. In the meantime, I can go to the local steel supplier, cut and drill the raw materials and get busy mounting panels on the new rack. How can that possibly make economic sense? How much energy is involved in all that?
Yup, shipping is a real problem for us little guys. Roberto just sold me a pallet of panels at a super low price. I didn’t need them, just can’t pass up such a bargain. Then there was the reality of a $500 shipping tab.
Well, this racking product that so impressed John is completely modular, meaning it is adjustable so it fits with any module AND it fits in a package you can ship UPS. Hooray! We’ll see if he can work out a deal to carry that line.
Another racking product I saw in show literature is a rackless system you can use on a commercial building with standing seam metal roofing. These little assemblies slip on the seam, you space them just so, snug them up and drop on the solar panel. Saves materials and labor costs. Great ideas.
New product news from my morning solar newsletters and not the Utah show has to be the worst idea ever. In addition to the current thin film offering that last a long time and the crystalline modules that seem to last forever, there are many other ways of getting power from the sun at much greater efficiencies. The problem with most of these is that they do not last very long. Some last only a few weeks.
The idea is that if they can get a super efficient panel to run 10-15 years, it may be economically feasible to build these disposable panels and just swap them out every 10 years! Now, I understand that land is expensive and if you can get more power out of an acre you can save some money. What about the cost of labor? What do you do with the scrap panels? It takes a lot of energy to make a panel and a lot to melt it down and start over. Why not just make forever panels and leave them alone?
I don’t think this idea is being promoted for rooftop, but imagine having to replace your home PV system every 10 years? I know when I get my new roof, I am going to get the best I can find and I really don’t want anybody stomping around up there wearing it down.
Besides, what does that do to the secondary market? You won’t be able to have such a broad choice of used panels at low prices that you have today, at least ones that actually make electricity. My thought on PV recycling is USE IT! Run it until it fades to nothing.
Speaking of recycling, someone has come up with a strange new idea to make it easier to recycle modules. You grind up a tree and make a cellulosic substrate on which to apply the active material and all the silver wires. Sounds like paper, to me, but cellulosic substrate sounds more impressive. Anyway, a hailstone cracks the glass or some other problem arises and it is time to recycle. Simply soak the panel in warm water and the cellulosic substrate dissolves and all of the valuable or tricky materials slide off into your waiting hands, leaving the glass and aluminum frames available for conventional recycling or even reuse.
Wait just a minute. MY modules are out in the weather every day, not that it ever rains in September. Do I really want a panel that dissolves when it gets wet??? I’m thinking there is a detail or two they didn’t mention in the press release. At least they are trying.
As far as my recycling efforts go, I just ordered a pallet of those FS-270 panels John is offering so cheap. 70 watt used thin film panels for $7! I’m bound to find something to do with them. Heck, I bet they’d make great stocking-stuffers come Christmas, birthday presents or even something for a kid’s science fair project. Ummm, maybe not, as they have an open circuit output of 83 volts. It is never a good idea to electrocute the nieces and nephews. Anyway, they look like good, cheap fun. Check them out on the sunelec.com home page.
My neighbor Connie got her power bill yesterday. It was $497. That was just the one for the house, she has another for the well. I got my bill today and it was $67. Mind you, $27 of that was for electricity and 40 is for taxes, fees, waste and corruption. So Connie only used $457 worth of electricity, but she gets mad when she hears about my tab. Well, I do, too. $67 will buy a really fantastic bottle of Cabernet, or two pretty good ones.
Part of the difference between her bill and mine is lifestyle and part is the fact that much of my farm is no longer connected to the co-op grid, connected instead to an oddball collection of solar projects. If somebody were to ask if you can really cut your power bill with solar, the answer would have to be “YES”, but if the question was whether or not you could save money, that’s a different deal. The less electricity you consume from a solar power system, the less it costs to build and vice versa. Saving energy saves you money, even when you have solar! Where you shop can make a big difference, too.
Connie and I have houses that are probably about the same size. Hers is older. Insulation? Don’t know. I’ve not seen in her attic or walls, but she found out there is none under the floor when a water leak required the floor be replaced. Mine has insulation in the floor and attic. Walls are R13, which is pretty minimal by today’s standard. She has a fridge and a chest freezer. I have 2 fridges and a chest freezer. She leaves lights on all the time. I don’t know what bulbs she has. I try to keep the lights off, but most are LED, in case somebody leaves them on. She has an electric water heater and mine is wood fired. Hers eats kilowatts and mine eats pine cones and junk mail during the summer. I think it is the air conditioning that is where her problem is, and she is not the only one I know with power bills above $400.
Connie is one hot babe. I mean HOT, as in Fahrenheit. She says she keeps the a/c at around 72 during the day and sets it cooler at night! My downstairs thermostat stays at 78 and the upstairs goes full on cold during the sunny hours because mine are both solar powered. To get my house to 72, I’d need a bigger inverter, maybe a pair of 8048s, to run both units at the same time and I’d need a much bigger battery to keep that going all night. The point is it would cost me more to run my house as cold as Connie’s, but from buying hardware, not from paying the power company. Of course, at some point, the hardware is paid for and the savings add up like dividend checks.
Some time when we both have time, I want to take a closer look at her insulation situation and her appliances to see where the power is really going, even though I suspect it is mainly the a/c. There’s a fix for that, if you’ve read the last half of the last solar a/c blog, the part about micro inverters. With a rig like that she could probably knock a couple of hundred bucks off the bill.
Here’s a bit of irony for you. As more regions in the world are getting their first taste of electricity, with solar, they are going crazy for a/c, which they’ve never had before. Projections for the solar build-out are being reassessed to cover the worldwide demand for air conditioning!
Ok, so let’s look at what’s going on at my house to save electricity and to replace the power company’s power with solar. First, let me say, I am not going off grid because it is nice to have the grid as my backup generator! Just flip the transfer switch and everything is back to normal $497 power bills.
Lights: Mostly LED, a few Compact Fluorescent because they haven’t died. I have one chandelier in the front hall with scads of wee incandescent candle bulbs. They’ve been there 25 years or so, I rarely use them and you could die trying to get that high to change them out. They are a problem I will leave to the next generation. Some lights get left on all the time. Some I’ve given up trying to turn them off, so all of the lighting in the house is on the solar circuits. Incidental to this, the internet satellite dish and the wifi are on this circuit, a legacy of when I had to keep my business running even when the power company was down. Old power bills are not available for research at this time, but I think I recall that when my old 24v solar power system came on it took about 200 kilowatt-hours (KWH) off the bill, or about $25 a month.
The old 24v system, including the Not-Really-8KW Melt-o-Matic inverter. The antique analog meter kind of gives balance to this digital stuff.
Of course, there was no electric water heater, but the grid powers a small fan in the outdoor wood furnace. That’s a fair trade-off there. This phase of the system was very limited, but also provided power for loads the house never saw. A Yamaha golf car replaced an F250 as my on-farm truck. At that time, the Yamaha was a just a load and not a battery resource, like it is in the present system. There were also lights and power tools run by the system and no attempt was ever made to meter this.
Firing up the amps with solar can save on the power bill, too.
Here is what the power consumption was looking like over a period of time. This is from my July 2019 power bill. The last “J” is the July bill, but for the June electricity. Look back 13 months to July 2018. That’s actually June, when it is pretty mild. August (July) ran on up to 837kwh. That’s without paying for the lights, of course. Note the plateau for November-February. That’s running the house without heating or cooling, aside from the air handler fan. Then in March we see another step down and then it just doesn’t go back up. There was another change.
What happened was the bigger 48v solar power system got switched over. It had been running for months, but there were some wiring changes and other things to consider, including minimizing downtime during the changeover. I knew the new system was stable, having run it alongside the 24v system. When I changed over, I put the extra power to work, cutting over the two fridges, freezer, home entertainment, some outlets, dishwasher, microwave and both coffee makers. We are serious about our coffee. That got us down to the 200kwh neighborhood, at least until cooling season begins.
The new 48v system under construction, before lightning blew up the 12kw inverter.
Getting through spring with most loads off the grid was easy. The challenge for summer was to get the a/c running on solar. The homemade inverter just couldn’t handle the surges. Read the a/c blogs to see what happened there. Short version is, it worked.
The new inverter under construction, using case and transformer of the old inverter. Note the MidNite Solar lightning catcher down near the bottom left. I love the cool blue glow and the thing actually works!
The homebrew inverter comes to life on the barely running 48v system. There are still 378 small solar panels to move over! Yeesh! Those stupid magnetic “light switches” are actually quite handy to stick to your system, just in case…
So here is the result of running the big cooling load, the lights and basic appliances on solar. The August bills from last year to this year dropped 600kwh, even while keeping the house cooler and powering 2 utility vehicles. So the next question is when do I upgrade my inverter to 10kw (I have the parts) and pile up some more battery capacity? The inverter upgrade is just a matter of finding time. Come January, the Solar Shed will be getting its last expansion, stretching from 80’ to over 100’, depending largely on how many working solar shingles I can come up with. Maybe an additional 3500 watts! The cost of building materials has gotten crazy, so we’ll get that part out of the way before we talk new batteries. The current set is in good shape, so no sense in spending 5 grand on a new monster battery, just yet.
The September 2019 power consumption of 210kwh is pretty remarkable when you consider how many days we had over 100 degrees F.
If you’ve not read some of my other posts, you may be wondering why I am not just running grid-tie. That’s not an option with our power co-op, so the only time we even talk about it is to gripe that we don’t have it. So, hybrid systems are the way we go. Proof is in the power bill that it is working.
Now as for Connie’s problem, I’m going to sit down with her and see if there is something we can do with solar to help her bill. Yeah, I could tell her to turn up the thermostat 5 degrees, but I don’t have a good track record getting women to do as I tell them, so I won’t bother. If we can cut $200 a month during the summer months with a microinverter conversion to her compressor, that could pay for itself in a reasonable time, especially with the cheap prices on the pv modules from Sun Electronics. I’m sure she has a heat pump (which I hate), but she might not see great savings in the winter if she really ices down the place, then. I’ll let you know if we come up with a successful plan.
After Hurricane Katrina, solar power took off in New Orleans. Long nights without power left folks wanting a little more control of their situation and rooftop solar took off.
How much of that was actually usable when the grid is down and how much was grid tie? I’m betting there was a lot of grid tie.
Nothing wrong with that, especially if you get real net metering. Figure up all the power you made and how much of a net surplus or deficit you had and money changes hands at the retail rate. In other words, if you used 1000kwh (kilowatt-hours) of grid power and the rate is 13 cents, then you sent the power company a check for $130. If you made 1000kwh more than you used, then the power company sent you a check for $130.
This is a really sweet deal, if you can get it. A few weeks ago, the Show and Tell post featured a Texas system owned by Daryl and some add-ons to a South Carolina system owned by Courtney. Both have that deal. Apparently, Louisiana has had that deal and now they want to change it. So much for the payback calculations.
I’m just going to use some round numbers, here, but they’ll be close to the real deal. Under the new deal, that begins with the new year, if you use an extra 1000kwh, you’ll still pay $130, but if you make an extra 1000kwh, you will get $34, based on the wholesale, or “avoided cost” rate the power company pays.
Ok, it’s actually worse than that. If your system makes an extra kwh today, you get your 3 pennies credited, but then tonight when you use a kwh to watch the evening news, they are going to charge you 13 pennies for the electricity they bought from you for 3! It cost you a dime for your own power! Figure, too, that a lot of power companies have extra connection fees for solar producers.
This puts you where I am with my power co-op. Florida law has been that the “regulated power provider” has to do net metering. As a co-op, however, they are exempt, so they make it foolishly expensive to connect grid tie solar.
Fret not, my friends, for there is a way for you to have your solar AND keep the lights on after a storm. It is called HYBRID solar. You will probably have to reconfigure your solar strings and buy some more gear, but what you will end up is not only a more versatile system, but one that makes more economic sense, as well.
If your grid tie system is in the most basic form, you have a number of solar panels in series connected to a string inverter. If this is your system, you remove the Sunny Boy and separate the seriously high voltage string(s) of modules into groups of, say 3, to get the voltages you need for charge controllers. Yeah, you gotta buy charge controllers. Maybe you only need one if you get the monster 300 amp Flex Max.
The output of the charge controller(s) goes to your new battery bank. The size of your battery bank is going to depend on how long you want to keep the lights on with solar power. If you have a lot of solar and a little bit of battery you can cook the life out of the battery in a hurry. A Flex Max can be turned down to accomodate the battery’s well being, but then you aren’t using all of your solar. I know it hurts to write that check for a big battery stack, but you won’t regret having it.
Now, you need a hybrid inverter to replace your string inverter. If you were doing your grid tie connection via a hybrid inverter to start with, then congrats. The “hybrid” inverter is called that because it can do grid tie, it can act as a standalone inverter, it can act like a UPS, it can charge batteries and sometimes they have other tricks.
I’ll tell you how you need to connect this new hybrid inverter in a moment, but you need one more thing. You need a transfer switch. This allows your inverter to connect to SOME or ALL of your house’s circuits. The simplest thing is to use a whole house transfer switch, which of course may cost more and will require that your new hybrid inverter be hefty enough to handle all the loads. You may think that you can pick and choose what you have running to stay within the inverter’s capabilities, but you will likely have someone in your house (I’m not mentioning names) that will want to live his/her life without limitations on the power they use. Count on it.
Otherwise, you can use a transfer switch, such is commonly used with backup generators to run power to essential circuits, leaving the clothes dryer and electric range out of the loop. These switches are cheaper and readily available but may present logistical issues, depending on where your main power panel is.
For a couple of examples, Tom has his whole house switched to the output of his GS8048 inverter pair. One didn’t quite handle it all, but the GS series can be paired for twice the output. With 16kw on tap, he doesn’t have to worry about running anything or everything, saying he has only seen the load go up to 10 kw. If one of GS8048s should fail, he can proceed with care on the other one until the bad one is repaired, but he’s never had a problem with either. He also has a power line connected to the input of his inverters. This is like a giant version of a UPS (Uninterruptible Power Supply) with the switches so set. Change the switches just a bit and the inverter is providing power to the house, with the grid on standby.
During the day, when there is plenty of sunshine, the batteries charge, the a/c cools (his setup has enough reserve power that the a/c starts without a Smart Start), the computers run, the fridge cools, etc. Nothing is going to or from the power company. There is no grid tie meter or agreement with the power company, so make sure the inverter never gets switched to “sell” mode. These modern smart meters will tell on you!
To minimize the load at night, baking and laundry are done during the day. Come night, the modest battery bank gets well into the evening before the inverter decides to switch back to grid to save the battery. The rest of the night, Tom pays his 13 cents for every kwh he uses. Overall, he doesn’t ever buy any of his own power at a markup and he for pay a lot of the bought kwh.
Tom has plenty of solar. By backing off on his nighttime a/c or investing in a bigger battery, he could probably eliminate his grid consumption altogether. He could keep the grid as his virtual backup generator or just give the power company the one-finger wave goodbye.
On my hybrid system, I don’t have the whole house connected and I don’t have one of those fancy interactive inverters. My transfer switch connects my inverter to the circuits you’d want if the grid goes down and a bit more, within the capacity of the inverter. The sun makes the power and I use it to run the freezer, two fridges, home entertainment, computer/internet, microwave, coffee pot etc. And the a/c. And the farm jalopies. There is no grid attached to the solar power system, so consumption has to stay within production. This is mostly determined by how much the a/c is used, as there is much more than enough power for everything else.
I’d use more of the kwh I produce if I had a bigger battery and inverter, but there is no charge for a grid tie connection and no paying out dimes for using my own kwh.
If you are new to solar, consider a hybrid system for both savings and power redundancy. If you are on grid tie and are or will be getting a raw deal, then consider converting to a hybrid system. Sun Electronics should have pretty much everything you need to make the change at a decent price and they back the stuff they sell. –Neal
John called the other day for some solar chit chat. He asked if I was still using my solar air conditioning and I replied that I was. It was holding up well in the blistering heat. He said, “You should write a blog about it.” Well, gee John, don’t you read this stuff?
There are 3 articles here in the tech blog, I think, about air conditioning with solar power, but maybe that isn’t obvious. The entire blog system got vaporized a while back and it has kind of come back in bits and pieces. Looks like webmaster Jorge has things finally under control. He has tweaked the graphics a bit though I see a few pictures that I need to replace. Hopefully, if you read through the whole lineup you’ll find some useful stuff.
But we were talking about a/c, weren’t we? And, mind you, we are talking about conventional systems, not the super efficient variable speed or inverter systems.
To recap, my first solar a/c was a 5000 BTU window unit, powered by my solar boat. 5000 BTU will nicely cool a bedroom, but if you keep it going you’ll find that it can cool down the entire house a degree or two and really help with the humidity. It is better than nothing!
When I got enough solar power to take a shot at running the central a/c, it almost worked, but my allegedly 8kw inverter on the 24v system couldn’t quite make the startup surge of either of my outdoor units. If it had started a compressor, it would not have been long before that inverter’s undersized transformer would have melted.
Somewhere in here I should point out that I have disconnected the big gray flex conduits that bring power from the disconnects on the wall to the a/c units and moved them to a different set of disconnects. The original disconnects are on grid power and the new ones have the solar power.
I figured the new 48v system with the big 12kw inverter would do the trick, because it worked for the previous owner. Alas, lightning got both the old 24v inverter and the new 48v inverter before I made the changeover. There was much sadness and a wee bit of despair over that.
So I found a source of electronic driver modules and built a new 5548, based on the transformer in the 12kw inverter. It would not make the surge power to start the compressor. I found a 10kw electronics module, but never got around to installing it, because I discovered a secret weapon for starting the a/c: the soft starter.
Soft starters, aka Smart Starter, are usually found in boats and motor coaches. The device alters the motor voltage and frequency to allow it to come up to speed slowly and stress-free. The boat or motor coach can avoid having an oversized generator just to start the a/c. The variable speed compressors should be alright without this option.
A Soft Starter Installed
Well, that sounded like what I needed, but they were 600 bucks. I found two at a marine salvage dealer for $100 each and installed them in my two outdoor units. It worked! The 5500 watt inverter will start and run EITHER a/c system, but I did not want to take a chance on BOTH systems trying to run.
This required a lockout. This can be done in the house, if both thermostats are handy. That is not the case at my house, but the compressors are side by side. The downstairs unit was fitted with a relay that connects in parallel to the main contactor. When the compressor is running, the new relay clicks and the Normally Closed contacts open. The thermostat wire to the upstairs compressor goes through those contacts, so the upstairs unit can run any time it wants, except when the downstairs unit is running. The downstairs unit runs anytime it needs to run. Use a 24vac relay or a more common dc relay with a rectifier if you should ever need a lockout.
Ok, so the big job of getting the a/c to run was done. Getting the house cool during the day was not a problem, but most of the day’s 24 hours are not sunny and the a/c units are inconveniently, totally off grid.
I knew I didn’t have enough battery. Nobody ever has enough battery. But I did have batteries that were sitting around at night doing nothing. They were in the electric farm trucks. Yeah, another 350 amp-hours. Enough to run the a/c at night! So now, instead of being plugged into the 120v charger, they are connected directly to the 48v system via Anderson plugs. They are usually charged by the time I need them in the morning.
An Electric Farm Jalopy
OK, I had the power, but no sense in damaging the batteries or shortening their life. Shallow cycles are better than deep cycles. Enter the programmable thermostats.
I had to work through some things to arrive at the final plan, but the basic idea was to get the house as cool as I could during the day, running the a/c as much as possible during the day, and running it as little as possible at night. If every day were sunny and bright then things would be much simpler, but this part of the alleged Sunshine State is often cloudy, especially in the late afternoon when it is hottest. Therefore, compromises were made.
When I was buying electricity, I would keep the thermostat downstairs at 78-80. Upstairs, unless the office was in use, was left at maybe 85. The final compromise that seems to work well is the downstairs thermostat is at a fixed 78 degrees, where it rarely turns on. The upstairs thermostat program is around 81 at night, jumps to 77 around breakfast and a little before 10am goes to 71.
On a really hot day it may only get down to 74, upstairs, but the rest of the cool is tumbling down the stairs. The 1.5 ton unit runs flat out with no cycling to cool the entire house. The only time the downstairs unit needs to run is when it is 100 outside and the wife is running the dryer, sucking in hot air, or I am using the oven. Yeah, I bake. If it is what we call a cool day (below 90) then the downstairs temp may go on down to the mid 70s.
I did have an alternating program on the thermostats to use the downstairs unit more, but there is a reason I am running the upstairs unit non-stop and I will eventually get to that.
Ideally, we’d chill the whole house during the day, but that takes BOTH a/c units and we just can’t do that at this time.
So far, the net result is that the house is cooler and more comfortable 24/7. We have a modest power bill while some of our neighbors are shelling out $400. Upstairs is super cool and that will be nice as we begin to dismantle my office up there and convert it back to a bedroom.
Now, for the reason we are running the upstairs unit so hard? You can get a hint by scrolling down to the “Micro-Inverter” post.
My friend Courtney had the idea of solar-powered a/c for folks who did not want to go through all the paperwork for a grid-tie system or the bigger expense of a large off-grid system. How about something you just attach to the a/c unit and it uses solar power? So, nice guy that I am, I volunteered my system as the guinea pig. I figured it would work, but did and still have reservations about how cost effective it would be.
In a nutshell, a group of solar panels connects to a group of microinverters, the output power adding up to the amount used by the compressor. No more than that. This way you won’t actually grid tie and send power back to the company. It all goes into the a/c. You won’t need a soft starter, either, since you have all that grid power behind you.
The microinverter 240vac line connects to the compressor motor side of the a/c units contactor. Good thing I buried some extra cable, huh? This way, the microinverters are only activated when the compressor is running. Annoyingly, they don’t start the power flow until the ac power has been on and stable for 5 minutes. That is a big reason we want to keep the compressor running pretty much continuously.
The panels we are using are 300 watt LGs, which Sun Electronics has in inventory at this writing. These work nicely with the Enphase 215 watt unit, which is a bit fussy about only using 60 cell modules. Yes, at peak times we are just tossing 85 watts, but the rest of the time we have a more constant and predictable power contribution.
My test compressor, in addition to the Smart Start, has 3 recording watt-hour meters in it. The top meter shows the microinverter contribution of 1949 watts at this moment (photo below). The middle meter indicates that the compressor is consuming 2020 watts. The bottom meter shows that the main power line is only having to kick in 75 watts! As great as that sounds, when you consider nights and cloudy times, the microinverter setup is providing around 65% of all we are using. There is definitely a savings there and it is definitely taking a load off my inverter during the day, as that is the “main power line” for the a/c.
Is it worth it? Not to me, of course, since I already have a solar power system, but for you? That will depend on what kinds of deals you can find on the components and what you have to do for installation. This is prime guerilla solar stuff, and having to get HOA approval, an engineering study to mount panels on the roof and stuff like that would really take the fun out of it. I don’t yet know what Courtney plans to do at the house he just bought, but in the meantime, the adventure continues. In a couple of months, we’ll see how well the heat pump runs on solar. I’m not a big fan of heat pumps on cold nights, but I don’t much enjoy cutting firewood for the outdoor wood furnace, either.–Neal
Did you hear about the solar panel fires on the roofs at various WalMarts? Don’t let it happen to you!
Little bits and pieces of this story have been coming out in the solar trade press for a few weeks, now. What I have gathered from this is that the rooftop solar power systems at 7 WalMarts have caught fire. The roofs were steel and the stores were not extensively damaged, but the WalMart folks are miffed enough to sue Tesla over the affair. Elon Musk’s Tesla did not install the systems, but they bought out Solar City, so it is a mess they inherited. Since Solar City was started by some cousins of Musk, you can wonder if the next family reunion might be a little tense.
So what does this have to do with you and YOUR solar power system?
Maybe nothing and I bring it up so that we can make sure. It is looking
like the problem started with connectors. Most of the panels I have
came with MC3 or MC4 connectors and I have worked with Tyco connectors.
MC3 and MC4 won’t fit together. Just a glance and you know that. MC4
and Tyco connectors look just alike, but won’t fit together. That’s
good because the lookalike parts have just the opposite polarity. You
will have to use adapters to mate these up.
The WalMart problem seems to involve mixing MC4 and Amphenol H4 connectors. They look alike and they fit. Amphenol makes no claim that an H4 is an MC4-compatible connector and vice-versa. The problem is, the Solar City installers used them interchangeably and the fit is a little sloppy. Word is, Solar City knew of the problem and had begun a program of swapping out for truly matching connectors. They just didn’t get to some in time and now the lawyers are swarming.
Something that can exacerbate the problem is not plugging them in
tight, even when everybody is using the same connector. Sometimes MC4s
are really quite snug, getting that rubber seal seated. When locked
they can be a real pain to get unlocked, if you are experimenting and it
would be really easy to forget and leave a connection half done. Aside
from a loose fit, that could be an invitation to water and corrosion.
In a low voltage system you might never have an issue with loose or mismatched connectors, but in grid tie, you can get into many hundreds of volts and a fair number of amps, resulting in conditions that will start and sustain an arc long enough to melt and then ignite connectors, which in turn can melt and ignite something else. Like a roof.
If your solar was installed by Solar City, have they come by to check
and update your system? Maybe YOU should. Of course, it is a good
idea to periodically check your system because STUFF HAPPENS, regardless
of who installed it. Are all the connectors snug and not charred or
melted? Does the insulation look good? Any brown patches or cracks on
the modules? Battery cables tight? You know what it is SUPPOSED to
look like, so just look for anything that doesn’t look right.
460 years ago, a Spaniard named Tristan de Luna y Arellano sailed into Penscola bay to establish the first European settlement. A few weeks later, before they even had all the ships unloaded, Luna and his 1500 colonists discovered the hurricane. I can only imagine the shock and terror as these folks held on for dear life as their makeshift houses blew away. It got worse after the storm was over, because one of the ships was on the beach, two or three, I think, were left floating, but were all beat up. The rest were just plain gone and we are just now finding what’s left of them. Those sunken vessels contained the bulk of their food and other supplies.
Welcome to the Sunshine State, amigo.
60 years ago, next month, Tropical Storm Irene slammed into Pensacola with a vengeance. It was relatively mild, but we huddled around a monopoly board with a candle in a sterling candlestick as our only light. Mom, an old hand at hurricanes, used the game to keep little brother and me calm as the wind howled and our tiny wood-framed house shuddered. Dad was away, manning his company’s emergency radio network. Not much damage came of that storm, but I think it must have left an impression on us, because you’ve never met two brothers with more flashlights, lanterns and emergency gear! Back in ’59, the emergency gear was that candle.
As I said, Mom was an old hand at hurricanes. Grandma, a widow, married an immigrant farmer in Palm Beach County, Florida, where they had some vivid memories of recent ‘canes when they went to build the new house on his Lake Okechobee plantation. The Everglades soil is soft and mushy, so huge cypress pilings were driven straight through to the limestone bedrock. A very sturdy house was attached. It was a good plan, because the house is still standing.
Hurricanes of the ’20s didn’t have the dike around Lake Okechobee, so the lake tended to get loose and add to peoples’ trouble. The water came up and people climbed trees to escape. So did the snakes. Gators just kind of floated up with the water level. A hurricane in the Everglades in the old days just plain sucked.
Cap’n Andy’s house was the best deal around and was the headquarters for local hurricane parties. Of course, the power went out, but the lights stayed bright with a good array of candles and oil lamps. Canasta and Akvavit provided distraction.
The 1939 ‘cane went right over the house. While they were in the eye, Mom and two men from the party went up to the levee to look around. As the eye began to pass, the two men had to hold onto Mom as they quickly made their way back to the house in the rising winds.
Not far away, a boy named Fred, whom I met half a century later, noticed a storm brewing. His Dad had gone into Ft. Myers where he saw the storm warning flags and hurried home to get hunkered down for a REAL storm. No TV, internet or satellite tracking in those days, the storm was on them before they knew it.
Indoor plumbing on Fred’s block meant a pitcher pump at the kitchen sink, the well directly below the house. When the storm was over, every house on the block was sitting catty-cornered, having been blown off their foundation blocks and weather-vaned with the wind. After the storm, they blocked the houses back up, but still at the odd angle. They kept the lights on with oil lamps, too, but that could have turned into a disaster as the house fell to the ground.
Fast forward to the 1970s and Mom and Dad would just move into their little mini motorhome when the power went out. They were far enough inland that the wind wouldn’t blow it over. With lights and a fridge, they had all the comforts of home, sort of.
Bro and I worked at WCOA radio, the town’s oldest and premier station. It was built like a bunker and we had a diesel generator to keep on the air. And we had Eddie, a former Navy steward and chef, who could really put on a spread. That bunch knew how to put on a hurricane party, though I spent the night sacked out on a bag of shipping peanuts in the quiet fallout shelter, because I knew when the winds died down I’d be called upon to fix whatever was broken at WCOA and other stations around town.
Then there was Katrina. That was a bad storm, but the incompetence of local officials made it a lot worse. The storm actually hit Mississippi, but there was plenty to go around.
Rain Webb, an artist who lived on a modest sailboat in a marina near one of the old coastal forts just east of New Orleans, decided he was going to ride out the storm in his boat. It was his home, after all, and he didn’t want to lose it. I was on an adventure aboard my solar launch Sun King in 2015 when I met Rain and heard his story.
First off, a boat is kind of a little survival shelter in itself. It is waterproof and has power, a galley, a bathroom and a bunk. The only problem is that it is out in the water, which is where the hurricane is the strongest. If left in port, there is absolutely no doubt the vessel would have been smashed or hurled ashore. Rain’s plan was to gather all the anchors and all the line he could find and head for protected waters. There’s the very shallow Lake Catherine and the salt marshes of the Intracoastal Waterway. He found a wide spot and put lines and anchors out in several directions, hoping that a least one or two would hold.
Sailboats tend to roll or heel, with the heavy keel returning them upright. And that is exactly what the boat did until the winds died down. Rain came out of that boat looking and feeling like he had been through the spin cycle of a washing machine. When it was all over, he had power and water and food and a roof over his head. He gathered his lines and motored back to port. (Don’t try this at home)
People have been surviving storms for a long time in a lot of ways. These days electricity is a big part of surviving a storm in some comfort. Getting that electricity directly from a generator is not the best way, though. The crew at Sun Electronics can help you with that. Ask about their solar and backup power kits.
As promised, I am passing along John’s description of the emergency backup system he put in his condo, years ago. Battery backup, with solar and a generator. The power does not usually stay off very long in big cities, but it doesn’t have to go off at all!
When I started Sun Electronics 35 years ago, I used my home office, it had been my Kyocera America East Coast and Latin America office. I set up this new office for Sun Electronics after working for them for 8 years.
I installed about 5 ARCO modules on my balcony railing , they were flat so I could use them as a bar for parties and just hanging out watching a nice view of the pool deck, Biscayne Bay and the Ocean. They were the perfect width and length 4 ft, by 1 foot. They were just for the office, then I added, a separate circuit breaker sub panel and added a Trace DR2424 inverter charger with an automatic transfer switch so I could have a hybrid system using a portable silent Honda portable gas generator. I could plug that back into grid to use for black outs or, by disconnecting the utility, and keep running the condo, ( the most important electric circuits: 2 refrigerator freezers (25 years old) sockets in kitchen, bedrooms and living room, minus the big loads 220 VAC appliances like stove, electric water heater and air conditioner. It was a great little hybrid system. We only integrated the Generator because Hurricane Wilma came along and put Miami back into the dark ages for 3 days. The system was so efficient and quiet that no one could see the solar panels and when the hurricane showed up we took them down and just used the backup power system with the Honda generator inverter, and 4 6V, 220 amp hr batteries wired in series (equaling 24 volts).
We went three days on that system and didn’t even use half the gasoline in the little lightweight portable, practically silent, generator because most of the time we didn’t need it after the batteries were charged and they took over we just had to disconnect the extension cord running to the generator out on the balcony that fed the house and the 70 amp battery charger in the inverter/charger.
It reminded me of the pelicans that flew by my window everyday up on the 14th floor Venetian Condominium. They’d flap their wings a couple of times (the generator) and then glide half a mile or more (the inverter output off the batteries, no noise, not even the Honda that I don’t think anyone ever noticed. Its illegal to bring gasloline into a high rise for running a generator on your balcony so we brought it up full in a cardboard box just before Hurricane hit, It was amazing to see all of Miami dark for three nights. If it had lasted more than one tank of gas I would have just reinstalled the panels on the balcony railing and lighten the load by at least half, goodby refrigerators, 6, 35 watt modules weren’t capable for that, but everything else was ok including microwave and fans a small 10 cu. Ft. refrigerator (75 watts) could have been added but just never did that.
If you are in the storm zone, we wish you all the best. If you have a backup power system that survived or can cobble something up, let us know what worked. If your system failed, let us know about that, too, so we can learn from it.
I spoke with John Sunday night. The blogs have been getting an overhaul and he is having trouble making posts, so I thought I’d let you know that he and the family flew out west to wait it out.
They are fine, but yes, he is worried about his home, the business and you, the customers.
The storm really made a mess of the Bahamas, and though nobody really knows what will happen, it looks like Miami is in good shape. Just a wiggle to the west and it could get really bad up the state or in Georgia or the Carolinas. Cross your fingers.
Right now it is 0330, Monday morning, and I don’t have all my resources, but will soon tell you about some of the discussions John and I have had about emergency power, including how he rigged a system in his his hi-rise apartment. Check some of the other blogs for tips too–Neal
I was working on a new series of posts on the basics, but something has come up…a hurricane. The projected trajectory has it going over Puerto Rico, where they’ve still got a lot of PTSD from the last one, then pass by John’s balcony in Miami and maybe come ashore somewhere between West Palm and Jacksonville. I have a friend in St. Augustine who has had chest deep water in his living room twice in recent years, so the Jacksonville area folks should be getting anxious. Earlier on it was expected to cross to the Gulf and rake the panhandle, where many have the same attitude as the folks in PR. I am happy to say it is no longer headed straight for MY HOUSE…unless it changes again. In our area, we had them coming in one right after another and then they quit about 15 years ago. People have forgotten and trees have not been trimmed along power lines.
Suddenly, PR grocery stores were out of bottled water and I’d bet the easy foods were gone, too. Now it is that way all up the Florida coast and beginning in Georgia. I get my water from a spring via a water-powered pump, so I don’t worry too much about bottled water. I have a couple of 300 gallon tanks I may put on a trailer and fill up for the neighbors’ use if the utility goes down after a storm. A couple of 5 gallon buckets and a ceramic filter kit from ebay can set you up with a filtering system that will filter pretty much any water. I used one of these on my boat and it’ll turn any creek, pond or mudhole into fresh drinking water.
I always try to keep a well-stocked pantry at home. Even when there isn’t a storm that has popped up, a well-stocked pantry can save you trips to the store and give you a greater variety of meals you can prepare on a whim. I also have lots of ramen noodle cups—not for survival food, but because I like them.
If you find yourself in the predicament that a storm is coming, your cupboards are bare and the supermarket has been picked over there are still options. (Tip: Walmart and some sporting goods stores have camping and survival food) Do people clean out the shelves with cornmeal or flour or cooking oil? Nope. You can make up some biscuits, cornbread muffins and tortillas before the power goes off and it is pretty easy to make them even without power or with your solar backup that you probably have, considering you are reading a solar blog. Try something like 3 scoops flour, one scoop water, yeast if you have it, a tablespoon of salt, a tablespoon of oil (I like coconut oil) and a dash of honey. If you have some sesame seeds, sunflower seeds, pecans, or carrot bits you can pitch in, then it starts getting downright tasty and nutritious! Make doughballs and bake them at 350 for just under a half hour. The stuff will keep and keep you alive. If you find a jar of jelly or peanut butter then you are doing good. Tortillas can be flour and/or meal with enough water to make a dough. Roll them out with a rolling pin or a bottle and fry them in oil. Stuff them with leftovers or canned beans or smear them with peanut butter and jelly. You can also make waffles, pancakes and hushpuppies! Oh, heck, you have a cookbook, don’t you?
If you have backup power from battery, solar or generator and need to keep the consumption down, a toaster oven and and induction cooktop are cheap, low power cooking tools. You reckon WalMart is going to sell out of them when a hurricane warning is posted? I doubt it. There is a foldout oven made for a Coleman gas camp stove, but it can be made to work, too, with a rocket stove that burns twigs and bark and stuff. A $10 coffee maker will make hot water for noodle cups. And coffee. Once the sun comes out, which is usually pretty quick, John has solar cooking ovens that you might want to look at BEFORE the storm. That’s really the key. How well you do after the storm can depend a lot on what you do before the storm. Oh, and make sure you have a manual can opener, too. I always keep a few of the GI P38 openers.
What about your power system? If you have a generator, top up the fuel and check the oil. Get your spare fuel cans topped up while you can. In PR, they still have a lot of generators left over from Maria and the various agencies have them fueled. Water the batteries, if you have them.
I know MY system has some vulnerabilities. Assess yours and do the best you can. Check mounting bolts and clips and make sure the wires are snugged in tight. In my case, I don’t reckon the batteries are going to blow away, but the solar roof tiles are only rated at 60mph. I find that distressing, but the only thing I could do about it is drill holes and insert special clips in each one. Yeah, and there are over 350 of them. Not going to happen. There are a lot of big panels mounted on rails trailing down from the roof of the Solar Shed. These are easily removed. My plan is to store some of them in a valley under a truck or trailer. The rest will go in the very sturdy garage at a house I own in another town nearby. I have stacks of unused solar shingles that would fly individually and cause some havoc, but they could be duct taped into large bricks that won’t blow away. If all goes well, the shed will still be there and functional. If not, I’ll bring the panels home and assess what I need to do to get the lights back on. I have a big diesel generator, well lots of them, but have not needed any in years. It probably would not hurt to get one back in good order, especially when I already have 500 gallons of fuel for it. If it comes to it, your car can keep the lights on and fridge cool if you have a good 12v inverter. If you don’t, Sun Electronics has them or even kits for an entire power system. Top up the car’s gas tank, as it makes a dandy generator when combined with an inverter. Each of my golf car-based farm vehicles has a 3kw inverter and can serve a field kitchen, if need be.
Having a few good candles or oil lamps and some long nose lighters is a good idea. They have about quit making decent matches, so I recommend the gas lighters. A LOW power flashlight, spare batteries, a small LED lantern and even those solar walk lights can provide enough light to get around the house until you can get the mains or backup power running.
Know where the first aid kit is, too. Get some cash out of the bank.
Yes, I am yammering on about what I would do, but it is to give you ideas for your own particular situation. John and I were talking a while back about survival shelters and power systems. Just bringing some panels and a few components indoors to a very sturdy area could be all it takes to get the power back quickly after a storm. Vast areas of Mississippi, Arkansas, Georgia and other tornado alley areas have storm shelters outdoors or built into the house. Keep a few panels and accessories in there for safe keeping, even if you don’t normally use solar power.
If you do end up with a bad storm and your neighbors did not prepare well, it would not hurt to have some of that homemade hardtack to hand out. Some places have been more dangerous after the storm than during. Don’t tell them you have fresh food in the fridge and other niceties and don’t leave the lights burning brightly or generator wailing away. If things get really desperate, otherwise nice neighbors might turn really bad if starving. I know a guy who keeps a grinder and a bushel of hard corn to hand out to the neighbors and zombies. Another way to deal with unprepared neighbors would be to have a cookout and make stone soup or hobo stew. Start with a pot of water and then invite folks to toss in thawing meat, canned veggies, spices and so forth. This can turn into quite a feast and is sure to promote good will.
One last thing, from personal experience, if the lights go out, don’t worry with it until after the storm is over. Every time you hear of folks who ran a generator in the garage and the fumes got into the house and killed everybody in the house. You’ll want the generator, if you use one, outside. During one hurricane, I set my newly acquired Onan outside and set it to running as soon as the lights went out. Well, the winds picked up and a big limb came down and jammed the generator throttle wide open. It blew up every CF light bulb (which cost $19 each back in the day) in the house. I ran out long enough to shut it down, which was also dangerous. So, my zeal to keep the lights on resulted in the death of my generator and all of my lights AND I got thoroughly soaked when shutting it down. Nah, don’t worry about the lights until after the storm if your backup system doesn’t handle the job for you. That’s why you have those LED flashlights, candles and lanterns, right?
If you are in the storm path, make your preps and hunker down. I wish you well and we’ll get back together after it’s over. –Neal
So you’ve been thinking about solar power or battery backup and wondering, “Can I do it myself?” Well, let’s stop for a moment if you really meant, “May I do it myself?” Those are two different things and I’ll talk about both, separately, but I wanted to point out both considerations. Without any more information, I’d say, “Maybe” to both.
Can you? Let’s talk about the physical requirements. I’m 65 years old, am 30 pounds too heavy, have too much blood pressure and all the bendy parts don’t bend like they used to. I know two other guys my age doing solar and one 75 year old. If you aren’t much worse off than that, you have potential.
This is my current project, in Phase 3. I call it my Solar Shed, with 11KW on the roof.
Can you pick up a 65 pound solar panel or battery? Lift the panel over your head? Somebody’s going to have to do it and it won’t climb up on the roof or rack by itself. There will be heavy stuff.
Are you clever enough to come up with some apparatus or con a buddy to help you lift a 200 pound inverter in place to bolt to the wall? Sometimes a good idea works better than brute force. Ratchet straps can raise a heavy inverter.
Do you have the tools? In addition to the usual hand tools, you may need big cutters, crimpers, soldering supplies, a basic volt/ohmmeter, ladder, screw gun and maybe more.
Do your tools have a lot of blood on them? None means you aren’t using them or are good at cleaning up. A little is inevitable, but too much may be a message to hire a pro.
Do you get gifts of tools at birthday and Christmas? If so, you may be ok. If not, why not? Do people think you are dangerous with a tool? Do family members run to call 911 when they see you with a power tool? Some people are just not meant to use tools.
Can you successfully, rewire a lamp, assemble a kid’s swing set or Ikea furniture or install a car stereo? If so, you may be ok. Courtney, 64, puts in the last screws in an arched solar pergola over his BBQ. Yeah, we bent them.
Do you have the knowledge of how solar power systems are connected and regulations for connecting them? If you don’t, there is a lot of free information on the Internet, diagrams of sample systems are available and folks like Sun Electronics offer kits and pre-fab hardware that requires minimal connection.
There are a couple of things I want to warn you about that may not be obvious to a newcomer. Most solar panels put out a modest voltage of 18-40 volts. That might give you a little tingle if wires were on a sweaty arm, but individually solar modules are pretty safe. HOWEVER, if you are using an MPPT type charge controller on a battery system (and you should for efficiency), you might have several panels wired in series for maybe 120-150 volts going into the charge controller. That much is going to do you harm if you touch it. Your panels normally use MC3, MC4 or Tyco connectors that won’t let you touch the harmful voltage, but you will use bare wire to connect to disconnects, fuse holders and the charge controller. I make a point of doing the bare wire work before plugging in the last panel connector and I’ve not been bitten yet. In my early days as a broadcast engineer I routinely worked with radio transmitters with 10,000 volt power supplies. My boss told me to always keep one hand in my pocket so that I couldn’t make a circuit through my heart if I slipped up. I never wore rings or a watch to work, either. Insulated gloves are a good idea, too.
64 year old Stan is upgrading the solar at his hunting camp.
Now if you think 150 volts is worrisome, and it is, consider that if you are connecting a grid tie system, you may be dealing with 600 volts!!! Now, aside from my advice to “DON’T TOUCH”, there is a characteristic of DC power of which you might not be aware. It arcs. If you try to unplug one of your MC4 cables while the system is charging or grid-tied, there is a good chance that the current will try to continue to flowing in the form of an arc. This can vaporize a connector, which will have to be replaced. Do your unplugging at night or when the system is shut down.
Did the last two paragraphs frighten you or did you just store that info away? If it scares you, you might start on something simpler or just call in a knowledgeable friend or a pro. If not, and you aren’t any older or feebler than I am, go for it! The hardest part may just be deciding what you want to do.
I take my solar power on adventures….or it takes me…thousands of miles.
One last thing, if you want to get some construction experience, working with laying out the structure, framing, roofing and wiring,—maybe even solar— consider volunteering with Habitat for Humanity or one of these groups that builds houses for disabled vets. You will learn skills, build confidence and find out if you are made for this sort of thing. —Neal
John and I have been talking about using solar power to survive in relative comfort after a storm. In my efforts to mostly eliminate my old 24v solar power system I realized I was putting together what would make a good example for survival power. Why did I not eliminate the 24v system completely? My solar electric launch, Sun King, is in the Solar Shed and needs to be kept charged up in the dark shed. In return, the onboard inverter runs my shop air compressor. Anyway, the old control board is coming down as my control room gets walls and a bit of civilization. Yup, Man Cave.
First, let’s talk about panels. Are your panels going to survive the storm? My Solar Shed PV shingles are rated for 60 mph, so there is a real good chance that winds from the right direction could do away with some or all of them. What about conventional panels? Believe it or not, there have been post storm studies to see what stayed put and what blew away. Click on the link for some interesting reading. https://rmi.org/wp-content/uploads/2018/06/Islands_SolarUnderStorm_Report_digitalJune122018.pdf
What I am proposing here is not storm resistant. In fact, my plan is to unplug and unbolt the panels and store them in a safe place. Under the house? Under the bed? I go for under my pickup truck which gets parked in a gulch, the panels duct taped into a heavy mass. Heck, we’ve even parked airplanes down there. The winds always blow right over anything we put down there. This won’t work if you are a coastal dweller. Maybe if you are a coastal dweller you should stuff them in the minivan and be somewhere else when the storm comes!
So, imagine the storm is passed and the winds have died down. Your house is livable, but there is no power. You want some lights and the fridge running at least. What I am suggesting here won’t run your central air, but if you have a 5000btu window unit, it will run and make a big difference, despite the small size.
First, retrieve your solar panels. You can make some temporary mounts by nailing up some 2x4s. There are usually plenty of them from houses that blew apart. Heck, you can even lash up some saplings using those Scout skill you got when you were 12. You just want your panels to be reasonably stable. I have put some flat on the ground for over a year. Whatever works. In this case, for my boat charger, I ran 3 treated 2x4s diagonally, nailed to the bottom of the solar shed eaves. Deck screws or ring shank nails are good about staying where you put them. I then put crossbar 2x4s spaced for the length of the panels.
If you routinely have some strong winds you might want to drive some angle iron into the ground to hold down the bottoms.
The panels, I use 3 to the rack, can be held in place with aluminum angle, about 2” lengths, and self drilling screws. I use longer screws in the wood. Don’t have a power screwdriver or cordless drill? How can you live that way???
You could just as easily screw the boards to fence posts or lean them against a dead car, in a pinch. Not shown, I also screwed the panels together.
Finished product. Well, it needs paint on the wood for protection if you keep it long term.
You can see I still have 6 more panels to put up on racks, at this point. The 1500 hp fan has not blown over the panels just leaning, so I am pretty confident about the ones on the racks.
Out of the weather, I used a scrap of plywood, 2 common fused disconnects, like you might use for an air conditioner compressor, and a cheap charge controller left over from evaluations for my Solar Yacht project. It’s a decent little controller, but the displays fail over time. ALWAYS connect the battery first so the controller can determine what voltage you are running, and THEN connect the panels. Although they look nice and professional, you don’t need preprinted placards to label things. A felt marker will get the message across. Ok, ok, I will put some printed labels up. There are websites and programs that let you design and print your own labels, signs and placards. You could premake the whole assembly on the plywood, with quick connectors and keep the unit in a safe place for rapid setup after the storm.
“Goof Off” and fine steel wool will clean off that tacky Magic Marker labelling when you get some proper decals.
If you are the suspicious type, you note that you don’t actually see any batteries. They are in the boat, 350amp-hours of 8v golf car batteries. This is actually how you might do batteries in a survival situation. If you had a battery bank, it is unlikely that it went away. If not, there will be cars, trucks, tractors, etc that have been crushed or flooded. Maybe your own. They can be a source of batteries. ASK, if possible. Don’t get shot for taking a battery! In this case, the boat has batteries and an inverter, so I am good to make power. I have a 2500 watt inverter for my 12v truck, when it is running. I have run a fridge with that and, more importantly, a coffeemaker, but you don’t really want to leave your car running. You did fill the tank before the storm, didn’t you? But, you still don’t want to leave it running. This little rig pictured above can charge the battery in your vehicle to run the inverter to run the fridge and Mr. Coffee. Microwave, too!
A golf car is a perfectly wonderful survival aid. Not only does it provide a LOT of battery, you can bolt on a 48v inverter for the newer ones (there are 36v inverters, but they are harder to come by) for portable power. There’s the transportation value, too. This same charging rig will automatically adjust to 48v operation. NOT ALL charge controllers go up to 48v, so check before you buy.
This 2500 watt modified sine wave inverter got painted red with the rest of the car, and ran the microwave just fine.
Oops, reality check, yeah my 2500 watt truck inverter will run those appliances, but what about the charging? 3×270 watt panels /12= is 67.5 amps. It is a 40 amp controller. Use just two of the panels instead of 3 and you are good. You math geniuses will note that two panels can produce 45 amps at 12v, but they won’t at that angle and if you use a pwm controller you’ll not get even close. On the 24v system it has room to spare with all 3 modules. Don’t forget to calculate this stuff and don’t forget to have all of the tools, fasteners, cables and connectors that you need. A dry run drill is a good way to check. Plastic totes are good for holding the kit, less panels and 2x4s.
OK, so what does this cost? I scrounged most of it. I had the disconnects left over from something else, but I think they are maybe $10 at Home Depot/Lowes. The charge controller is an MPPT unit that I already had. Cheap pwm controllers are readily available for a throwaway system like this, or you can get an industrial strength controller for maybe $500. Your choice. In a pinch, if you match the panel voltage to the battery voltage and keep the load up, you can get away without a charge controller, but be forewarned that inverters can be fussy about their voltage range and batteries can be killed from over or under charging. Batteries, ideally, are something you already have in a car, boat, tractor, golf car, RV etc. You might get an inexpensive survival inverter, even if you have a nice one in a PV power system. We are talking about backup, here. A fridge and a microwave WILL run on the so-called modified sine wave models. John does not have the absolute cheapest inverters, but he has good prices on inverters with a good track record. MOST cheap inverters you see on ebay have drastically exaggerated ratings. If you don’t have any of this stuff, the Puerto Rico kits that John put together after their storm are pretty much everything you need at a great price.
Ok, how do you get the power into the house? If you have a generator plug and a transfer switch you just plug it in with an appropriate cable. The circuits on the transfer box need to be within reason for the amount of power you have. Forget the clothes dryer, range and central air. Concentrate on lights, microwave, fridge and coffee pot. (Coffee makers also make hot water for Ramen noodles, soups, teas, etc.) DON’T have the generator plug? Use a HEAVY DUTY (12 ga) extension cord and run it in through a window. Use an outlet strip to plug in the fundamental loads. OR don’t use the outlet strip, which guarantees nobody will run Mr. Keurig and the microwave and fridge at the same time, possibly blowing a fuse and ending it all. Umm, you do have a spare fuse, don’t you?
OK, these are just some things to think about as Hurricane Season approaches. There are so many ways to prep for power after the lines go down!