Don’t Forget Solar Thermal Power
It is easy to get all excited about making electricity with solar panels, but electricity isn’t the only thing the sun can do. It makes heat. Using a solar water heater is a whole lot simpler and cheaper than making enough electricity to run an electric water heater. Online, you can find plans to build a unit that fits into a window that will help heat your house. With a solar oven, you can even cook a meal. With a magnifying glass you can start a campfire with the sun’s heat.
Don’t overlook solar thermal power. Even my cat knows how to harness the sun’s heat on a cool morning.
–Neal
Mystery Dust
I laughed this morning as I read a news story about West Virginia and Maryland residents wondering about a “mystery dust” that was coating their cars and homes. We have it here in NW Florida, too, but it is no mystery.
Really, it’s SPRINGTIME, y’all. I hear tell that up north it is still cold and snowy, so it may be some of OUR pollen has blown up there. My pickup trucks are crusted with yellow pine pollen. My wife’s freshly-painted car (twice, because a large deer caved in the side of it, right after the first painting) is crusted and guess what else?
We are at week two into air conditioning. Not John’s super efficient new solar units, though. Mine are the ordinary kind, run with brute force solar. The temperatures have been pretty mild. 68, this morning and the high will be in the low 80s, so the a/c isn’t working very hard and I have not had to squeeze all the watts out of my solar panels. The time is coming though and I will have to deal with the mystery dust. Get your car wash bucket and that long handled scrubber and get busy to get those watts fired up again.–Neal
PS: The buck walked it off. The car needed a new fender and door.
How Does Solar A/C Work?
A few years ago, John and I and another friend of mine looked into solar a/c . It wasn’t ready for primetime. I experimented with some schemes, but just went with brute force to run my old-timey Rheem the old fashion way. Here’s how the new-fangled contraptions John is selling work. BTW, check out his posts at johnssolarblog.com.
First we’ll look at how the old-timey units work. Outside, there’s a big box with a motor and a compressor. When your thermostat clicks, it sends a 24 volt alternating current signal to a relay in the outside box. That connects 240vac to the motor and the compressor spins.  So does your power meter, or at least the mechanical ones. Cha ching!  This is an all or nothing thing. Thousands of watts are flowing for the next 10 minutes until the thermostat clicks off.
The compressor compresses the refrigerant gas into a liquid. Compressing the gas makes it hot and coils around the sides of the box get rid of the heat. The now-warmish liquid goes to a closet in the house where the air handler lives. There the liquid expands back into a gas in another radiator called an A-coil because of its shape. The evaporating gas gets nearly freezing cold and a blower blows the cold off the A-coil through the ductwork to the various rooms. Got that?
Evolution. Some years back, electronic speed controls got added with an inverter circuit. This is not exactly like the inverter that runs your house. It is more of a variable frequency device to speed up or slow down a motor. There are some variants, but basically we speed up or slow down the compressor. These inverter a/c units run pretty much ALL the time at lower rate instead of full speed ahead for a few minutes and then stopping for a while. They are very efficient and very quiet.
When I was helping my friend Courtney refurb his Georgia farmhouse, we lived in the carriage house. Each bedroom had a window unit and the one in my room would put a freight train to shame at making noise. He bought a dual head mini split system and put it in himself one weekend. Mini splits work kind of like a regular split system, except they have an air handler for each room instead of the closet with an air handler for the whole house. Anyway, this was a variable rate inverter system and it was glorious. You had to listen hard to even know it was running inside and might walk by the outside unit without noticing it was running. The power bill went down. Life was good. But the unit was not solar powered.
Ok, we have established two general types of a/c. There’s the all or none conventional systems and there are the variable speed inverter systems. Let’s look at how the inverter system works a little closer.
The compressor cannot use the 240 vac directly because the 60 Hz frequency of the power line will only run a motor at one speed. The 240 vac goes to a rectifier to make a DC power supply. Some use a high voltage of several hundred volts and some use a lower voltage, say, about what a solar panel puts out. The inverter takes the DC power and chops it up at whatever rate is needed for the a/c to keep the temperature right. If you come in from vacation, the unit was off and the house is hot, it will come up to full speed ahead, just like my antique unit, and then slow down when it hits temp. If the thermostat detects it is getting cooler, it slows down. Warmer, faster.
Courtney and I looked into modifying a standard unit a few years back, but decided that R&D mistakes could get expensive and void the warranty. Never mind product liability issues if we sold one and it caused trouble. We both went the brute force route at our homes. John was demoralized because he really wanted to sell solar a/c. Oh there were some commercial units, but who would pay 5 grand for a window unit the size of a Kia Seoul?
Still, we were on the right track and folks like Gree, big players in the Asian and European markets fine tuned their DC and inverter sections for solar. Here’s how it works. The AC is converted to DC, same as always, but only as needed to keep up. If a solar power source is connected, there is little or no draw from the power company. Wait a minute, though! I’ve seen units the capacity of my antique being run with 1000 watts or less of solar. MY unit draws 3 kw! Ah, now we’ve hit upon the secret.
MY unit has to have lots of kilowatts of solar, battery and inverter because MY unit starts hard and runs full blast when it is running. The solar unit, once the set temperature is reached, slows down to the point where all the power is coming from that/those panel(s)! There is a good chance, unless it is very hot. that the solar is all you need during the day. Of course, the power company runs it at night and cloudy days. Can you add a few more panels and a battery to go 24/7? Sorry, I can’t answer that question unless I take a look at specific units. Can you add more panels and have it solar powered more of the time? Looks that way, but get a copy of the manual. I just talked to John and he says he will send me all the literature.
So what’s the economic outlook here? Like most things where you save money through efficiency, there is a higher price up front. The savings come over time. Should you change out your 5 year old a/c for a new solar model? A fairly new conventional system may already be pretty efficient and you should have a lot of life left in it. A solar energy tax credit might help with the numbers, though. If you have an antique like mine and it is powered by The Power Company, it is probably a no brainer. The economics over the brute force method are good. Smaller inverter, smaller battery, fewer panels.Â
There’s a lot going for this cool update. Check with John or Roberto for available models and pricing.   Looks like 4 ton units will be arriving soon.–Neal
A Good Way to Get Started
A few posts back I went out in the shed and dragged out some examples of ways you could put together a small solar power system for camping or to get you by after a storm. They are functionally equivalent to some of the systems you may see in the corner of the page when browsing the internet, but cheaper.
They are also a good way to get started in solar. Gain some experience. Learn some things without the mistakes being too expensive.
The reason I bring this up is that John says he has a ton (probably literally) of small odds and ends of panels. He is offering them as low as 12 cents/watt, but in the same breath mentions that he likes to haggle. Who knows what kind of deal you can make AND end up with a package that will keep the lights on during your next blackout or keep the devices charged on a camp out.
Get several panels with the same voltage and put them in parallel to stack your power. OR get identical panels to use in series. We’ve made posts about such details and you can look that up.
GO FOR IT!
–Neal
John’s Gone Bonkers!
That’s nothing new. He gets excited about things, especially solar. At the top of some pages you’ll see a link to John Kimball’s Blog. Take it. I don’t know why, but you have to scroll down and wait a few seconds for the blog to appear.
I like to check his blog. Sometimes, like me, he will go a while without posting, but then it is a furious storm. I like it when he posts fish pictures from the jetty. Where’re the fish pics, John?
His latest joy is in discovering that Gree is, or is about to be, releasing solar powered AC. I got interested in that a few years ago. John and I and Courtney and I were brainstorming on the subject. There were all sorts of ways of dealing with it.  I eventually went the cheapest, shortest route, using the 30+ year old systems I already had running and “paid for.” Actually, some big makers were playing with it several years ago. The most likely prospects were from overseas and the import game can be fraught with numerous perils.
Gree is pretty good kit and maybe John will give us some details, soon. It may be your A/C guy can just drop one in, soon.
On a related note, one gent with whom I correspond has a house with pool in Miami and he wants to use solar to heat it. My first thought is direct solar thermal. Heck, I was with some folks out in Hayward, California, a couple of decades ago and saw their neighbors had big coils of black plastic pipe clamped to their roofs. Water from the pool pump ran through the pipe and came out warm. Cheap. Simple.
Last time I saw a pool heater (we tend to swim in the creek, here in NW Florida) was in the last century, in Miami It was gas-fired. Gas seems to have fallen from favor, these days. Jeff, the guy with the pool that needs heating, has investigated and discovered that heat pumps are all the rage for heating the pool. BIG heat pumps. Heat pumps with the capacity to heat every house on the block. Well, pools have a lot of thermal mass and are not too well insulated, so I guess it can take a lot. It will be interesting to see how that turns out.
In the meantime, watch John’s Blog for details on the Gree hardware. And if you are a DIY kind of person, you might want to scroll through MY blog, back in time for various ways I have eased into solar A/C and heat. The photo at the top of the page has to do with at least one iteration. You’ll find at least 3 different plans. Maybe as spring gets closer I will revisit the subject and summarize. Meanwhile, just know that solar A/C is real, at least at my house.–Neal
Solar Farms Banned!
In recent news, some solar farm projects have been rejected for environmental reasons! Bear with me a while.
In 1815, William McVoy petitioned the Spanish governor for a grant of land at Chinmele. The grant was first denied because that area was listed as Indian lands. McVoy’s countered, “What Indians?” The Indians had seen the Spaniards, like McVoy, moving up from the south and the Americans moving in from the north, with Andrew Jackson just being an overall pain, so they had left Chinmele. McVoy got his grant and set off a land rush over the next 5 years.
Among the restrictions on a land grant, usually 800 arpents or several hundred acres, were that you would keep the land for yourself, you would inhabit and you would cultivate within two years. That’s the deal Juan Malagosa agreed to when he got a grant at Chinmele in 1820. Almost immediately, he “flipped” the land to American Andrew Mitchell. Methinks this was a prearranged deal. Everybody knew that Spain’s grip on La Florida was slipping and by 1821, Florida was welcomed to the USA, where it would remain for 40 years.
Andy Mitchell built a mill and seemed to do well, cutting timber on the public land above his mill. The thing about trees is that when it rains, the leaves soften the impact of the rain drops and the leaves on the ground act like a sponge. Water is absorbed into the earth and aquifers are replenished. Andy’s mill did well until a big rainfall came to the rolling hills above the mill and the runoff rushed down and blew out his dam. Some dam failure modes make it impossible to rebuild.
Fast forward to the 20th century. 1948. Chinmele is now known as McDavid, Florida, and Claude Welch is building a mill just downstream from Andrew Mitchell’s. Claude was a real go-getter, one of the first in the area to have running water (from a water-powered pump) and electricity (from a Delco-Light). The gristmill down the road in Bogia was closing, so Claude bought the turbine and stones from the Franklin Mill up in Brewton, Alabama. I’m guessing Claude liked his cornbread made with fresh meal. Everything was going well with the new dam and the mill house was constructed.  However, up on the hill, Florida Pulp and Paper Company, new owners of the land, clear cut all the pines up there and the rains came. Once again, Mitchell Creek flooded and blew out Claude’s new dam.  It was a small breach, but too expensive to repair and today there is barely any sign of it. Are you starting to see a pattern?
Fast forward again to the 21st century. Next Era Energy wants to build a solar farm on the hill. Surveys, studies, archaeological assessments and environmental reviews all pass muster and the trees are all cut off so that 600 acres of solar panels can be installed. And then it rains…
It has been a while since anyone has built a dam, but every time it rains a river of mud flows down Bogia Road toward the Baptist meeting house. Drive carefully. Next day, the bobcats come out (the stubby metal kind) come out and attempt to drag the lost acreage back up the hill. Grass is planted, terraces are formed and hay bales and mud fences are staked out. Eventually they’ll get it under control.
So, you see, there can be environmental consequences of trying to save the environment with solar. Since the Cotton Creek plant was put in, two more have been placed in our county. That’s 1800 acres of rolling hills lost to agriculture and forestry and now needing constant attention until the erosion is under control.
Now, I am all for solar. I have my solar and I have a financial interest in Next Era, but I think we need to be careful. One study I’ve seen declares if we just cover roof tops with solar we’ll have enough to go around. Amazon, WalMart and other companies with big stores and distribution centers are adding solar to their roofs at no additional demand on land. How about parking lots? A lot of people just leave their cars running to keep them cool while shopping here in Florida. Imagine having the parking lot at WalMart or Home Depot shaded with a solar canopy! Canals are being covered with solar, with the added benefit of reduced evaporation. There are plenty of ways that solar can be deployed without taking over croplands or causing environmental problems.
There has been a huge rush to deploy solar and I think the rush is a big part of the problem. Solar and wind only provide about 20% of US power, so hopefully lessons will be learned from these early installations will be applied to improve things in the future. And localities that have banned or limited solar projects can get the power they need without causing havoc.–Neal
P.S. Paying attention to history can help avoid making the same mistakes over and over again, but it seems history has been on the back burner here in Chinmele, 32568. My cohorts and I have been on a documentary and archaeological quest for the history of this little town. Pass by on US 29 and about all you will see is the church, Post Office, the firehouse and the store. We’ve found railroads, sawmills, potsherds and lithics, cemeteries, a camp meeting ground, a quarantine camp, hotels and remnants of Andrew Mitchell’s occupation. In the early 1960s, a gentleman was building a house on the edge of the Hot Pond, aka Lake Chinmele, when a group of Indians arrived by canoe, went to a specific spot and dug up the ashes of their ancestral council fire. They left, never to be seen there again. About a century and a half after McVoy declared the land abandoned by the Indians, the Creeks apparently made it official. Yeah, I know. Sometimes John talks about fish in his blog, so I get to talk about history every once in a while.
Troubleshooting II
Last time I wrote of dealing with one of two recent issues that have come up in my system. Michael C. wrote to me regarding an alternative to the water heater dummy load to test or calibrate inverter power. He pointed out that the air handlers—the box in the hall closet– of heat pump and a/c systems usually have a big resistive heating coil built in. When systems get replaced the air handlers get chucked, except maybe the A coil, which contains copper. An old air handler or two could make a dandy air-cooled dummy load and maybe even for free! Add the power controllers from ebay and an ammeter and you are ready to burn some kilowatts. Thanks for the idea, Michael.
The other problem I mentioned was that the slave inverter of my pair of Sunny Island 6048 inverters was slamming off and on when the temperature got around 27 degrees or below. These were bought at auction with no warranty, so I am on my own, here. Intermittent problems can be maddening. When I worked in computer service I might drive across 3 states or fly across the country only to find things running just fine when I got there. You can’t fix it when it ain’t broke.
To that end, I’d try to break it. Computers used to be real fussy about temperature, so I might hose down the circuit board with freon or a heat gun to see if that would affect it. Or maybe start wiggling cables. This is where I started on my inverters.
After being disappointed by a lack of error codes in the built in diagnostics, I pulled the covers on both inverters. The inverters are in a cabinet that barely allows the covers to be removed, so it involves a prybar to deflect the cabinet a wee bit. Naturally, the power was disconnected as I looked for dark spots on the circuit boards and took a wrench to the huge DC power cables coming in from the battery bank. No problems there. I unplugged and replugged every connector to exorcise any minor corrosion that might be there.
Something was missing, though. It appears that there are components on the back half of the chassis and it looks like you can only access this side if the entire inverter is removed from the cabinet. While I admire the packaging effort that DC Solar went to in designing this system, it has some maintainability issues. I am NOT going to take those inverters out unless they are stone cold dead. I noted that the circuit boards have 2 connectors marked FAN and I suspect that neither fan is working on the master unit. The fans are on the back side, naturally. There is a hot smell when the generator is running to equalize batteries, I suspect as a result of no fans.
I can deal with that to some degree with external fans. Furthermore, the unit derates itself if it gets too warm, so it isn’t hurting anything.
As for the principal issue, 27 degrees does not happen a lot in Florida. I think we have had 2 nights at or below that, so for now, I will just toss a shipping blanket over the outer cabinet to hold in the self-generated heat a bit or even put a small heater in the cabinet…even a light bulb.
I know that sounds like a cop out, but there’s the old adage, “If it ain’t broke don’t fix it.” Yes, I know it is broke, if only a little bit, but it could be a lot worse. The oft-ignored motto of the medical profession is, “First, do no harm.” Getting those mostly working inverters out of that tight cabinet would provide all sorts of opportunity to do inadvertent harm and those are really expensive inverters. In the meantime, I will keep watch on the forums and see if someone comes up with a solution. Sending the inverter to the factory with a note that says it won’t work below 27 degrees will not likely result in a fix and will result in lots of postage for a heavy package that might get even physically broken in shipping.
So let’s modify the old adage. If it ain’t really, REALLY broke, don’t fix it. (Unless it is under warranty.)
–Neal
Troubleshooting
Sometimes things just don’t go right. Sometimes it is an easy fix. Sometimes it requires test equipment. Usually a simple multimeter will do, but not this time.
My main inverter bank has developed a problem. Maybe it has been there as long as I have had it and it just hasn’t shown itself. It happens at about 27 degrees and, this being Florida, we don’t get many dips that low. This showed up in our big freeze a couple of weeks ago and I figured it would happen again with the forecast of 26 degrees this morning. I avoided the problem by shutting it off and going to my old homebrew inverter.
The yellow inverter on the left is cold natured.Â
I don’t want to work either in freezing temperatures.
A friend in cooler North Carolina has the same main inverter setup and the same problem when cold. I went to a forum to which we belong and nobody ever heard of such a thing. Big help, those guys. These are complex and sophisticated beasts with all sorts of internal diagnostics. I will get into that later and see what I can find.
The main inverter is a pair of Sunny Islands, 6kw each, from 48v. Each makes half of the 240 the house uses. Lose one and a lot of stuff won’t work. Like the heat or a/c. In this case, before it just quits altogether, it behaves rather badly, slamming off and on, making some nasty spikes in voltage. These events wiped out my motion detector lights, but nothing else. If it had taken out the big TV and the sound system, there’d be war.
It is the homebrew inverter that I need to troubleshoot. I got greedy, this morning, and switched from the wood furnace to the heat pump before the wife was done with breakfast. She turns on everything at once and while ANYTHING is okay, EVERYTHING is not, at least when the heat pump is running and the smaller inverter is in use. And the heater is on out in the Man Cave. The lights went out. I should’ve just thrown another log in the firebox.
Knowing that the Sunny doesn’t like the cold and knowing that this morning was going to be cold, I shut down the one inverter and fired up the other. The Sunny is outside in a cabinet and the homebrew is inside where its heat can help keep the plants warm without running the heater so much. A while back I had to replace the power module with a new one and the new ones never come in calibrated. They are usually set pretty low. I go through a routine of plugging in heaters and coffee pots and whatever else I can think of to use power, but they all have thermostats and begin cycling on and off after a few minutes. I used to have an old electric range to use, but it is no longer available and it cycled, too, even on high. What I need is a Dummy Load.
 
The tiny screws on the wee blue boxes–potentiometers– adjust the voltage, max power, overload, etc. on the power module
The dummy load is something of which I learned as a young broadcast engineer. Rather than test a transmitter over the air, you put it into a dummy load to soak up the power while you make the adjustments. Ham radio operators may remember the Heathkit Cantenna(TM). It was a paint bucket full of mineral oil and a 50 ohm resistor. Usually you could get your adjustments made before the oil expanded enough to start oozing out. That’s what I need to tune my inverter…a Cantenna! A BIG ONE!
Disclaimer, if you go solar, you probably won’t need to test at this level. Mainstream gear probably won’t ever need adjustment, though there is some Chinese gear that is prone to having inflated power ratings. I could name names… The main point is to let you know it is ok to think outside the box.
I have had a little scheme in the back of my mind for a while and it turns out it could be combined with my dummy load. Two birds with one rock. Since I went to a wood-fired boiler for my hot water, my electric water heater has been in a shed out back. It’ll hold 300 pounds of water and it has two 4500 watt heating elements. If I add variable power controls I’ll have a giant cantenna! A hair blower can add the extra kilowatt I need to tweak out the inverter to 10kw. That’s one bird.
The other one? During the course of a sunny day, the batteries get topped up by noon and power just gets wasted. What if I could store some of that power that is otherwise lost? Remember, power can be stored in many ways, not just in a battery. Many of the other ways are LOTS cheaper and longer lasting than batteries, too! Heat is useful and it is easy to store. Heat is something I need in the solar shed on mornings like this.
Variable power controllers for the dummy load
There are some really neat electronic gadgets available on Ebay. I found a couple of variable power controllers, like industrial strength lamp dimmers, rated for 6000 watts and 240 volts, just right for the two heating elements on the water tank. I think the pair of them were under 30 bucks. I should have the wire I need. The hard part will be getting the tank out of the shed. It has been there long enough that it might not want to leave. So you see, put a big breaker in the power box and run a line to the water heater via the two variable power controllers. Oh, yeah, put some water in it. Then all I have to do is watch the meters as I gradually twist he screw to crank the power to 10,000 watts. Simple and precise.
Now about the heating idea.  300 pounds of water raised 100 degrees F above ambient will give you 30,000 BTUs of stored heat. That’s about enough to heat your house for an hour on a really cold morning and maybe my Man Cave all night. If the tank were stripped of insulation and place in an insulated box full of sand, then the BTUs really start to add up.Â
Many better charge controllers have an auxiliary function relay. It won’t handle a lot of power, but it is plenty to drive a contactor that will drive a big load. On two of the inverters I have you can set the relay to trip at a predetermined setting, so when the batteries top up, we can keep getting power from the panels instead of wasting it. Sending a/c power to the elements will use the power, but also use up some inverter capacity, unless you have a second inverter. You could also tap battery voltage. 48vdc will not give you a lot of heat, but maybe enough, maybe not. That’s something I will experiment with. Another method might be to divert the higher DC string voltage from the input of a charge controller to the heating element. Just bear in mind that DC power switching is prone to arcing, so you need slightly different tactics for doing so. There’s probably an Ebay gadget for that.
Getting the heat out of the tank and into the room can be done by pumping or by normal convective flow in a thermosiphon. All sorts of heat exchanger options are available, hydronic baseboard radiators being probably the easiest, though not commonly available in Florida. That’s what mail order is for.
So there’s the plan. Now to see if I can get the water heater out of the shed without breaking something. But first, it is up to 49 outside. I need to go see if the Sunny Islands will start back up…and start thinking about how to deal with that issue. It may be as simple as tossing a horse blanket over the cabinet.
–Neal
Poly, Mono or Thin Film?
My lifelong friend Courtney, based in North Carolina, is gradually retiring from his job and having fun developing a line of solar equipment. I think he is missing the point of retirement, but to each his own. For one project, he bought a pickup load of panels from a nearby dealer and was surprised by a couple of things.
The panels he bought were of the noncrystalline variety, very common these days and usually what you get if you need the most watts in the least space. He was working on a mobile system, so high energy density is a must. This is what I am looking at on my Solar Yacht project. The big surprise was that the dealer had tons of polycrystalline panels he could not sell because nobody wanted them. Reason given? Folks think that mono panels do better in cloudy conditions.
I asked John about that. Sun Electronics has literal tons of panels in locations all over the country and every kind you can imagine. As long as he has been in the solar business, he should know a thing or two about this, so I asked. To a degree, the North Carolina guy is right, but sometimes this varies by the panel maker. But if you really want the best partial sunlight performance, you go with thin film modules.
Thin film panels are much lower density, or bigger for the amount of watts they put out, BUT, they perform much better in low light and they are cheap A while back I bought a pallet of 70 watt First Solar thin film panels from John. I use them in two places around my farm and I think they cost around 7 cents per watt. I think shipping cost more than the actual panels! They work fine.
Monos? I bought a truckload of them for my solar yacht project. As newer, denser panels have come out, I may not use them there. Meanwhile, they are wired into my solar shed.
I have over 300 of the raunchiest looking old poly panels you ever saw, but they make a lot of power from good sun and were very cheap.
What about low light performance? I never really tracked poly vs. mono, but I did run tests and convinced myself that the thin films hold up better. Honestly, you get a cloudy day and you don’t get much power. If this is an issue, then there are two ways to deal with it. You can add more panels or buy a bigger battery in an off grid system. For a grid-tie system, you just don’t shave as much off your power bills on those days.
So which panel do you need? If energy density is an issue, like on my boat or Courtney’s trailers, go with mono. Better yet, if the back side gets any exposure, go with mono bifacial panels. Now, I am convinced that the ordinary old poly panels on my launch Sun King put out more than label rating in the summer when reflections off the water are hitting the back sheets. Mono and bifacial are your choice for most power in the least space. Expect to pay a little more for the boost.
I am planning to put in a new east-facing array when I can get the land cleared and will put in a north facing array when I expand the Solar Shed. These will more than likely be poly. The last 10 panel array I installed was a bunch of inexpensive polys. Space is not an issue and when the time is right and I see a super deal, I will go down to Sun’s Miami warehouse and get a load.
Poly panels are usually blue and with a close look you can see the crystals.
Thin films? The ones I have work great. Because most of the ones available do not have an aluminum frame, they can be a little tricky to mount unless you are on a regular racking system. Price, when you can find them, is usually pretty cheap.
My advice? If space is not critical, go for whatever panels John has at the best price. Better yet, see if he has any in a warehouse in your area to reduce shipping cost. If you can save some on trucking or even go fetch them yourself you will find yourself with an even better deal. Again, John has tons of panels, thousands of panels. Get yourself a deal.
Oh, and that bit about mono panels having better output in low light? If the deal is right, just buy more of the other panels!
–Neal
Emergency Power, Part 2–My First System
I have been promising Part 2 for a long time. In fact, I meant to write this one before what ended up as Part 1. Life has been bizarre and hectic, here on the farm. So much so, that backup power has proved itself and I have questioned why I even have a connection to the power company!
Here is a recount of the latest disaster. Last summer I got the power company to snug up my sagging power line. Tree limbs, hurricanes, age and whatever had it sagging to the point I thought I might snag it with a tractor or something. Power Guy snugged it up, perhaps a bit too much. Then the weather turns cold and it shrinks, getting tighter. A twang from a tree limb and the whole house would twang at about a G Flat. It looked like the edge of the gable was out a little from the bricks, but I had other things to concern me, so I ignored it. Then, another tree branch hit and there was no twang. The line was slack again, because it had pulled the gable loose from the rest of the house. Â
That gable has been fine for decades. In one hurricane two very large pine trees fell on the line and it held. The combination of things finally got it and when I saw it I said…oh never mind, you get the idea. I quickly got into the attic with some ratchet straps to secure things and called the power company to cut the line so I could pull on the wall harder than their line was pulling. For about a week, the line was coiled up over by the pole and I was busy reassembling the end of my house and removing the tree that had been dropping limbs. The house was put back together with deck screws instead of nails and four steel cables run from that gable well into the house for a good grip. This is something that might have freaked me out a little, but we went through such bizarre repairs on a friend’s Georgia farmhouse that this seemed almost trivial by comparison.
We went 6 and a half days without the power company and operated normally. Good weather helped, but so did a backup power system with a good set of batteries. Had the weather turned to where my solar system would not help with the charging, I can charge with gasoline, propane or diesel.
But I want to talk about my original backup system. I quickly realized that if you are on a budget and someday want to have solar power, buying the solar modules is not the best place to start, especially back 30 years ago when panels were really expensive. You start with the balance of system stuff: inverter, batteries, transfer switch, etc.
This was also appealing because while my house was under construction, a hurricane knocked out our power for 4 days. So 4 days seemed to be a good goal for sizing the battery when I got to that part.
Below is a diagram, somewhat simplified, of how my house was wired to start. Pretty much everybody does it this way, except usually room lights and outlets are on the same breaker. My light circuits are lights only. It really doesn’t matter which way you go when you think about it. There are maybe 8 outlets in my bedroom, for example and only one is actually used for a lamp, a phone charger and the laptop charger. Not a big deal. There are plenty of other breakers in my big panel for lots of things to eat watts, but this is, as I said, simplified.
Simplified Home Wiring–Before
Initially I pulled just the lighting wires from their breakers, but eventually pulled the 120v kitchen circuits, as well, and put them on new breakers in a sub panel. This is just a smaller version of the main breaker panel. Something has to source power to the sub panel and that was a Trace PS-2524. This was similar to the SW-2524, except it had a remote meter panel. The Trace was mounted in my attic and the meter panel was in the laundry room with the main panel. Â
The attic? Yeah, well, maybe that was not the best place. It gets Florida hot up there, but not enough to exceed the specs on the rugged inverter. There just wasn’t a good place to put it in the laundry room.Â
The Trace converts 24vdc to 120vac with a sine wave. It is rated at 2500 watts and has lots of surge capacity. It can invert, it can charge the batteries, it has an automatic transfer switch built in and it can even do grid tie reverse feed. Every thing you needed when you got around to buying panels and racking. Good gear, but they don’t make it anymore. There’s newer, better, cheaper stuff, like the Schneider SW-4024 or 4048. Also, some inverters will make 240 vac output for more versatility. My Trace would chain to another to make 240vac, but that would be doubly expensive.
One of the newly-freed breakers in the main panel was replaced with a 40 amp breaker to run to the input of the Trace. The output of the Trace fed the sub panel. A bank of 8 golf car batteries, like the Sun 230 John sells, soaked up and released power as required.
This is what it looked like with the backup power system.
Home Wiring With Backup Power
I forgot that there was also a line to power my computer, as that was important to how I made a living.  When I first had just the lights (and computer) on the system it would run 4 days without over-discharging the batteries. I quickly felt the need to keep the fridge going as well as Mr. Coffee and the microwave. You know, necessities of life. That was first implemented with an extension cord down the stairs and reduced battery life to 2 days. Pulling a few more wires out of the main box and connecting to the sub panel made it much neater. When the battery started getting punky, I could run the big generator, but that was not needed. Mostly. Most outages were pretty short, but during one memorable storm aftermath, the lines were down more than a month. I would wake up and fire up the diesel generator. This would charge the batteries, warm up the water heater, cover all the big loads. When I got ready to go to work I shut off the generator and life at home for the wife was pretty normal. In the evening, upon returning home, I might (or not) fire up the generator again. If needed, a load of laundry could be done. My wife refused to use a clothesline! Every time the generator ran it ran efficiently because it had a good load and it did not have to run continuously. In 5 weeks, it only consumed 42 gallons of fuel!
So let’s go over some details, including things I would do differently. If I had had the room, I would not have put the backup system in the attic. The heat never bothered the inverter, but probably caused the batteries to use more water.
The batteries were put in industrial battery racks, 4 over 4. This is a standard thing, but not the best way. The best way was the way the old Delco Light systems worked, with the batteries on a stair step. That made it much easier to check and water the batteries or clean and tighten terminals. These are necessary chores and more likely to get done if done easily.
Hmmm, add an inverter, a charge controller and a few solar panels to that and you’d have a complete home power system. 90 years ago, this WAS a complete home power system, just without the solar. Anyway, the stair-step battery rack is something I like for lead acid batteries. With sealed batteries, a plain stack will do.
The batteries were in a corner, the wall sheathed in fire-resistant drywall. A wooden box covered it.  The box was painted with latex paint to make it acid resistant. The top was fitted with a small fan and dryer duct hose to carry away the hydrogen gas. The floor was covered with vinyl sheet material to be acid resistant and I usually left some baking soda sprinkled on the floor in case of spills.
The inverter itself, like most modern inverters, contained the transfer switch to immediately switch to backup power if the mains failed. Nothing extra to buy.
So here we have a handy backup power system. What happens when your budget is ready to include solar? Stay tuned until next time.–Neal
Fake Solar News
After Hurricane Ian, John and Rich and I wondered how the massive solar farms held up in Florida. I forget how many Rich calculated were in the path, but it involved millions of panels. Florida Power and Light has said nothing that I have heard on the subject. Yeah, they were busy restoring power. I get it, but seems like they’d like to brag if it went well.
A story came out on a community called Babcock Ranch.  They bill themselves as being America’s First Solar Town. The gist of it was that this is a solar powered town with its own solar farm. Houses were all built to or beyond Florida’s strict building code.  Lines are underground, so there is nothing to blow down. Special attention was paid to drainage, so the town did not flood, even though it is just a few miles from ground zero. Damage, they say, was limited some lost shingles and the lights never went out.
Well, that sounds great, but nobody gave any details on the solar…like how big the battery bank is. I thought that was suspicious. Turns out, the story was a bit of an exaggeration. They are NOT solar powered, though some homes and businesses have their own panels. They are directly powered off the FPL grid. The solar farm provides much of the power by day and a gas plant provides power at night. The solar farm and a substation are right at the town and with no exposed lines there was nothing to break. I would guess they are not far from the power plant either.
Watching FPL build two solar farms near my place I have noted that the panel mounts are well planted and they are using some serious concrete poles for the main transmission lines. Apparently this transmission upgrade is widespread because FPL got most of the lights back on very quickly after Ian passed.
I am all for solar saving the day, but geez, don’t just make stuff up! Tell us real stories.
–Neal
Emergency Power, Part 1
We are spoiled when it comes to power. When the lights go out, there are plenty of ways to get them back on.
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A Little Late
Hopefully, not too late. Last time I promised a series on emergency backup power, with and without solar. I also promised it would take a while because I’d need to take some pictures and make some drawings. Writing a column isn’t just writing. Writing is easy, like running off at the mouth, but people like pictures. And a picture is worth a thousand words.
We’ve had a good year, from the standpoint of hurricanes. Summer was cloudy and rainy, which are not good for solar, but it was relatively calm. Calm in Florida. Folks that got floods and tornadoes will disagree and they may find the backup power series useful, too. When I get to it. Now autumn is here. September is great. It stops raining, we have lots of sunshine and temperatures drop into the 80s. Love it! But now, suddenly, the hurricanes are popping up. One just trashed Puerto Rico and now there’s another brewing. After practicing on Cuba, it appears to be heading to Tampa. Oops, now the cone includes MY house! OK, that is getting personal.
I promise that what follows will be rambling and somewhat incoherent. I have been distracted recently, but there there may be a useful nugget in here.
It started last Friday. Andy, my brother, usually comes up on his day off. We trade books , shoot guns and or ride motorcycles (instead of working on the blog). He knows not to come too early as I am not a morning person, but I do make an effort to get up before noon when he is coming up. So, I puttered around and he didn’t show up. I tried texting him, but a DR650, his recent ride in the eternal quest for THE ONE, makes a bit of noise and vibration and it is not uncommon for a call to be missed.
I puttered around until after lunch and decided I would venture off to the museum, in Century, where one of my solar installations was having an issue. I decided I needed some wind in my face, like an old dawg with his head out the pickup truck window, so I went to pick out a motorcycle. The solar-charged Zero motorcycle is a hoot and costs nothing to run, but I felt I needed some rumble, too, so I picked the barely-muffled Shadow ACE.Â
I looked for a meter to take for troubleshooting, but I could not find one. I swear, I think the electrical field of my 400 solar panels has disrupted the time and space continuum, as tools just disappear for weeks at a time and then mysteriously reappear on my workbench. Anyway, no meter. Oh well, I’m a pro. I can improvise.
So, I roar off to the park to check out the lion’s head fountain that is no longer flowing. This is a direct drive system with no battery or electronics. Dirt simple. I check and there are no leaves on the panels, which are mounted inconspicuously on top of a trellis. That leaves the pump or wiring or a bad panel. I suspect the pump and have both a spare and an external test pump. I really don’t want to have to swap the submersible pump, because I’d have to siphon off the pool, open up the plug, fish wires through for the new pump, drag 100 yards of hose to refill the pool and buy chemicals to keep the pool from turning into a swamp. Algae would give the poor lion a green beard beard and we can’t have that.
Assured that the panels were clear, I went behind the fountain and connected the external pump to the wires and nothing happened. Hmmmph. I bumped the wires together and there should have been a tiny spark, but there was none. Then…did you ever test a 9 volt battery by touching it to your tongue? Well, yes I did and there was only the slightest tingle, like a bad 9v battery. Well, well well. Oh, before you try that, be aware of what you are testing. I have some panels that put out 90 volts, which would turn a tongue into fried bacon. These two panels in series in bright sunshine might make 12v and are pretty mild. The average full size panel is 36 to about 48v, so don’t test them that way. Find your meter.
The fact that I got a slight tingle, along with a visual inspection pretty well assured that the wires were intact. The squirrels had not gnawed anything.
The solar panels on the system at the museum’s blacksmith shop are shiny new things that Roberto sent from Sun Electronics and are working great. The ones on the fountain were used and abused. I did not bring the prettiest ones because I am planning an expansion of the Solar Shed and need these solar shingles for my roof, preferably making some additional kilowatts. Net result is I am going to have to not be so frugal and grab a replacement panel from my private reserve to replace the bad one. No big deal, but I’ll have to go back and get the truck and a ladder, etc. Oh, by the way, when I got home the meter had returned to my workbench after I had taste tested the solar panels at the park.
Back at the house, I started gathering stuff to go get the lion flowing again and the phone rang. Maybe that was Andy. He was a few weeks from retirement and looking forward to riding all over the country on his various motorcycles. Maybe he was ready to declare that the Suzuki was going to be the perfect ride. You know, THE ONE. Nope. He had been riding a back road in the next county over and had slowed to ease around a mud hole. A tire slipped in the rut. He fell off, broke his neck and died in an instant.
So, I’ve been a little busy with family stuff the past week.
–Neal
Go Big or Learn to Make Do
Solar isn’t just for hippies anymore. You won’t see many 12v systems, powering just a few bulbs and a radio salvaged from a car. Nope, solar is powering the American Dream home. 3BR, 2 Bath and every electrical device you can imagine. Trying to run everything at once is where you can run into trouble.
Tom powered his home, shop and hangar with a 10 kw inverter. It did well. He and Jane had to THINK sometimes about what all was going on. It could power everything, but not at once. When lightning got the inverter, he replaced it with an 8kw unit. Nope, not enough. Fortunately, most of the better inverters will stack and adding the second, adding up to 16kw was great. No worries.
My system has evolved. A 2500 watt inverter/charger was fantastic as a backup for lights, fridge, microwave and Mr. Coffee. I ran it for years. If I had had solar, it could have replaced that much of my power bill.
Then came a bit of solar and I did what I said. The basic circuits were already separated, so it was a snap to replace the old inverter with the new, complicated slightly by the fact that the new inverter was over 200 feet away in the Solar Shed.. I had repaired Tom’s old 10kw inverter and since I had 10kw to work with, I put the air conditioner compressors on the load. Everything except the stove and the laundry room and some outlets was on solar. You know the next goal was to go whole house, but there were matters of battery and cable size. The thought of getting any more cable in the ground without hitting the existing pipes and wires is scary, but eventually I was able to repurpose about 75 amps worth of copper that was already buried.
The white box is a soft starter inside the control area of one of my ancient a/c compressors.
Then the inverter blew again. I reworked with different electronics and enhanced lightning protection, but the electronics were only good for 5kw. I didn’t care to spend a lot on a new inverter when I could get the electronics for a hundred bucks. Now I had more load than inverter. Addition of a soft starter module in each a/c compressor allowed them to start on less surge current. I also added a simple relay so that only one compressor would run at a time. It worked! Eventually I located a module that would allow me to up the inverter to run 10kw. I left the soft starters and lockouts in place. I now had enough power for the whole house, if done in moderation. The house is 2 story, 2000 sq ft, all electric, except no water heater. Water comes from a wood furnace.
Tom’s old inverter gets another upgrade.
The battery pile had grown and I could spend more time off grid. Cloudy, rainy days would put the stove and laundry back on the grid. I found some gear cheap at an auction that I integrated into what I had and it is a very nice system. It could be better with some more cable in the ground, but I like it. Another 1500 amp hours of battery and a 12kw inverter stack. Cloudy days are still an issue if you get a lot of them. I may need 100 kwh from the grid in a month at times. I have further upgrades in the works. The ultimate goal is to make it so my wife doesn’t have to ask if she can use the dryer or do dishes or charge her buggy. Make it totally transparent to any user without any special consideration. Almost there! And on a budget! (Bear in mind that I haven’t had a job in 16 years, and don’t want one, so I do have to watch the budget.)
Now take Mike, our last example, he got in on the same auction deal I did, so we have identical inverter setups and pretty close to the same battery. His house is 2 story (plus basement office), all electric, though newer and probably better insulated, as he is more to the north end of the country. He has gradually been bringing the system up and a couple of times the inverters have shut down, probably from an overload trip. He asked for suggestions.Â
Mike and I both run a pair of these Sunny Island inverters for 12kw at 240v. Not my first choice, but very good gear.
He could add more inverters, which he already has, but I think he can do just fine with a few mods. His wife cooks a lot, so there’s the stove. Add in the dryer and 2 air conditioners and you are pushing the limit. Do a load of dishes when the water heater is on and you are tripped. He is best off if life can go on without special planning, SO, here goes. While you want to use the heaviest load during the day, I’d say do the softstart and lockouts on the a/c units. That’ll knock 3kw off the peak, I suspect. Use programmable thermostats on the a/c and heat to maximize use during the day to help the batteries. I bet he already has a timer on the water heater. Set it to heat up at a time when it is unlikely that any other big loads are running. You know your lifestyle, so adjust accordingly. If you do laundry mid day and dishes after supper, run the water heater in the morning. Simple.
You’ll have big loads that have to coexist, but you can save a bunch on hardware by making just a few changes. –Neal
Slow Down! Think Ahead!
A week or so ago, the big news was that California has banned gas car sales after a certain date. Many of the car makers have announced they will be all electric by a certain date. Did anybody stop to think they might be getting ahead of themselves?   You know, where’s all the electricity going to come from???
Here we are, just days later, and California is asking residents to NOT charge their electric vehicles because they don’t have enough power to keep the lights on and charge the cars. Hoo boy, who’da thunk it?
If you have solar power or are planning it, maybe you should plan ahead about including power for an EV. Looks like there isn’t going to be any way around them. I just got with John on another pallet of panels for me. I have a second inverter set, already, so I should be EV ready. Or be able to charge the E-motorcycle and the farm buggies on cloudy days when the clothes dryer is running.
Ok, I know what you are thinking. How’re you going to afford a bunch of panels? Well, John is out in Nevada, now, testing, packing and shipping around 5000 modules he just bought at a great price. He will have to get done with the logistics and get things priced, but you can bet on a good price. They will be stored on the left coast, so if you are in California where there isn’t enough electricity to go around, these panels will be close and shipping won’t be as expensive.  Give it a week or so and watch for an email from sunelec.com, announcing a price.
If you are on the other side of the country, John will have a super deal on some huge bifacial panels he got recently. 475 watts big! I have been begging him to get them priced with the Graciela seal of approval.  John would just as soon sell them below cost, but Graciela insists there has to be at least a little profit. I guess that’s fair. Otherwise, we’d have to buy our solar stuff elsewhere. at a higher price. Watch for notice when these are ready.
With hurricane season here, even though the hurricanes have been holding off while parts of the country get flooded the old fashion way, we still could get a good hit. Therefore, I am working on a series of posts on basic and advance power backup systems, including some that could be used as a building block to eventually having a full solar power system for your house. Trust me, I am an expert on all the expensive mistakes you can make, so you’ll learn how to avoid them. I just have to do a little “artwork” on system diagrams. I will get to it when I do. Making the announcement will give me incentive to get it done to keep you from yelling at me.
Also planned, what’s the cheapest, mostest, bestest solar system for you? I need to draw up some diagrams for that, too.
In the meantime, I’ll work on John to get some prices on these new acquisitions.  You don’t need to wait on that, though, there are some really surprising prices already posted on the website.–Neal
FREE-E-E-E!
How would John do this? FREEEEEEE STUFF. No, he’d probably expand that a bit. Make it a bit more grand.
A company in the solar training business sent me a cool solar tee shirt. It has a house with solar panels on it and the slogan “Savings Through The Roof.” Cool. It had been so long since I’d filled out the form that I forgot who was sending it. They wisely put their name on a sleeve. Companies do stuff like that, “free stuff to the first 100 clicks” to see if anybody is reading their newsletters.
My wife thinks my free “KRAMER, built to rock hard” guitar shirt is naughty. I can’t help it if she or anybody else has a dirty mind! I wear it with a chalkstripe blazer.
The point of subscribing to the newsletters is not to get the free stuff, though, it is to learn something or keep up with the latest news. I found a notice of an auction with 9000 solar panels in one. John jumped on a plane and bought most of them. He’s been scrambling ever since to figure how to get them inspected, sorted and shipped. I don’t know the details, but be sure you’ll see some more great deals, soon.
If you do a search for solar newsletters you’ll find a lot of stuff you don’t need. Do we really need to know there’re 3 GW of solar panels held up in customs because the wrong people made them? Or how many megawatts were installed in India this year? Probably not.
However, Congress just passed the Nothing To Do With Reducing Inflation Act (or something like that) last week and the newsletters are full of info that just might be useful to you if buying solar or an electric car. Ferinstance, order your new EV soon because when the IRA goes into effect that $7500 rebate will only apply to cars with batteries and motors and such made in USA or Canada with homegrown minerals and components. There are no such cars!
Well, anyway, talking about free stuff, I bet you were expecting me to tell you John would give you a free tee shirt. Nope, all you’ll get from him is “The World’s Cheapest Solar” stuff. As a consolation prize, I’ll tell you where you can get a free book download with some interesting insights on solar panels, batteries and battery charging. It is useful stuff. I think they will mention a charge controller they make. It sounds pretty good, but too small for my projects. This URL is the FREE page of a company that deals in off the wall science. The solar book is good. For some of the other stuff, you might want to have a tinfoil hat handy!
For free tee shirts, visit your local blood bank and save a life! I have about 100 shirts and all kinds of other swag from them. –Neal
Fun With Microinverters
What is a microinverter and how can you use it?
You have solar panels and you want to do something with the DC power, you’ll often need some kind of inverter. The microinverter was designed as a grid tie inverter to pump your solar DC into the power grid. There’s more.
In the beginning there was a thing called a synchronous inverter. It was a big box on the wall that took all of your solar power and pumped it into the power line. It was a grid-tie inverter, but nobody had come up with that catchy term. It could stop or run your power meter backwards. Nobody could really afford a bunch of solar in those days, so the power company didn’t catch on and charge a bunch extra.
Then somebody came up with putting a wee grid-tie inverter on the back of EACH solar panel. First time I heard of that I thought it was a really bonehead idea. They have evolved and from what I see, these are the number one way of doing grid-tie. I think it probably boils down to labor cost. I had a case of them to play with and will try to pass along some of the fun things you can do with them.
Each module (sometimes it is 2 modules per micro) gets a microinverter bolted to the back. The racking goes up on the roof. Then a long black cable with funny connectors along its length is spread out along the roof. A pass thru is installed to get the cable through the roof and it connects to a breaker or cutoff at the house’s panel or someplace handy for the Fire Department to cut the power.. Finally, as you bolt the panels into place, you plug the connectors to the microinverters. Ta da!
Yeah, there are inspections and you have to make arrangements with The Power Company. Often, TPC will make you wait a month or two before you can turn it on, will make you pay for insurance, charge a bunch every month for the capacity of your system and then give you just a little money for your Kilowatt Hours or KWH. Or, you could get lucky and live in a net metering area. Then grid tie is a good deal.
Let’s say you are among the lucky few to be in on the net metering gravy train. What happens when the lights go out? Well, they go out. There’s no storage. Some of the big box GT inverters and some of the latest micros can provide daytime islanding, or power in your house at a vastly reduced rate, probably to account for passing clouds and such. It is enough to keep the fridge and a few lights on.
So those are the basics. What if you do NOT want to go with grid-tie, but have a case of microinverters and a pallet of solar panels? That’s where it gets fun.
If you root around way back in the blog, you may still find some stuff I did with a/c. I’m in Florida and a/c is very dear to me. Watching the weather reports at night, I think a/c is becoming important to everybody else! Under the hood of your outside unit, there is a contactor or relay that uses the 24vac signal from your indoor thermostat to connect the 240 volts to run the compressor. If you connect the AC side of your GT microinverters to the compressor side of that relay and size your solar source to just a smidgen less that what the a/c uses the solar power will be directly consumed by the a/c and none will flow back to the grid. No need to involve TPC and pay their fees. This works. I had both of my compressors heavily instrumented and had all the figures. There are downsides to this method. When the compressor switches on, there is a mandatory 5 minute delay before the micro kicks in. I improved performance by just running the smaller upstairs unit pretty much all the time during the day. Another problem is those dang clouds. Forget that “Sunshine State” crap. It ain’t so. And then it didn’t work at all at night.
The Mark II version of this system DID work at night. The Enphase inverters will limit power to what they can handle. There are some cheapo Chinese GT inverters on Ebay that will blow up if given a high current source because they do not limit. SO, I connected the solar panels through a charge controller to a stack of golf car batteries, like the Sun 230 that John and Roberto sell. Actually, I connected a lot of panels to charge the batteries. Then I connected the batteries to the DC inputs of the appropriate number of micros. NOW, the sun was not wasted when the a/c was off, it went into batteries. And because there were batteries, they worked when running the a/c at night!
That big black cable that connects the micros is awfully expensive. If you find a deal on a sack full of micros, make sure they come with the “drops” as they are called. The cables are not only weatherproof, but they also contain a communications channel, which can enable another neat trick. Let’s say you want to counter power use in the entire house, but not go grid tie. There are several companies that make communications controllers that can sense the overall flow of power and throttle back the flow before any can escape to the grid. Your meter will rat you out if you grid tie without approval. If that happens, the big white truck comes and then you got some ‘splaining to do, like Lucy Ricardo. Connect the AC side of the micro to a 240v breaker in the panel and run the sensor coils from the main lines coming in from the grid to your communications controller. The battery trick should work here, too, but unless you have micros with the limited AC backup function it is still not a good solution for the grid failure condition. If you are buying batteries and charge controllers you are better going ahead with a hybrid system that I go on about so often.
There’s another really bonkers trick you can try if you have a battery hybrid or off grid system. I was one of many of the people who bought the bankruptcy inventory of DC Solar company’s solar trailers. Complete system in portable format. Some of these guys must have terminal disease or be just plain crazy with some of the stunts they’ve pulled. Some blew up some expensive hardware and some came up with some cool hacks.
What happens if you have an off-grid power system and connect a string of microinverters to the output of your inverter? The micros think they are syncing with the grid. Well, if you have the communications system with the limiting sensors the micros will help out with your load. Say, you could have the 12kw inverter that came on the trailer just idling while the micros sync to it and provide all the power for your 3kw a/c and the 500 watt fridge. But if you don’t have the limiter or if you have the older, stupid micros, they will actually backfeed through the inverter and charge your battery. There is some possible peril here, depending on battery and system size. As the battery approaches full, the regular charge controllers will back down and the only charging or overcharging will come from the micros. With the size of the batteries we got with our trailer systems it is unlikely you’d have enough micro capacity to damage anything, as long as the micro capacity is smaller than what the transistors in the inverter can handle. Use this trick with caution.
What I have not yet come up with is a really good way for someone like my neighbor EJ who has a really, really bad deal on a grid tie system full of microinverters to fully utilize his solar capability without spending a lot more money. Best I can come up at this point is to get the communication controller, shut down the grid export and to tell TPC what they can do with their GT meter and associated monthly fees. By scheduling most of his heavy power use during the daytime he could make a serious dent in his power bill.
–Neal
EVs and Solar Charging
Electric Vehicles (EVs) have been around over a century and have been very popular and practical in some areas. In other areas, not so much. They are perfect for forklifts, golf cars and neighborhood vehicles. Even delivery vehicles with a fixed, predictable route.
Electric automobiles were tried early on and their usefulness was limited. The same goes today, but they are becoming more practical. Good thing, because the government seems Hell bent on forcing everybody to get one.
There are a problems with everybody getting one. They can’t build them fast enough. There isn’t enough copper and rare earth materials for the motors. We don’t have enough lithium and cobalt for the batteries. Not everybody can afford one. Not everybody wants one. On the other hand, nobody wants to pay $4-5 a gallon, or more, for gas.
Hurry up and wait! Standard government procedure. We have the materials in this country, but the government won’t let the miners mine. There needs to be a coordinated effort to get this done if we are going to do it.
Then there is the other problem. How do we find enough electricity to charge the cars when many parts of the US and other countries can barely keep the lights on? They shut down the coal plants, knock down the hydroelectric dams and turn off the nukes. How’s that going to help? I guess we’ll just have to do it ourselves. I do.
I own 4 electric vehicles, with more on the way. No electric road cars, mind you. My most-used road vehicle only has 280,000 miles on it and it just got a new fan belt, so it’ll be a while before I need a new car. I figure if they get a Supercharger station at every Interstate rest area and Cracker Barrel restaurant, a 400 mile battery car will be ready for prime time. They exist, but they cost more than I am willing to pay.
In the meantime, my farm and recreational EV fleet is charged by solar…very carefully.
There are the two electric trucklets, proof that someone with idle time and a torch should not be left unsupervised. The gray one, is based on a Yamaha G19 golf car (not cart) and the other (red) is based on a Zone NEV. Previously I had full sized pickups for farm chores and these jalopies are actually better than the pickups. These have been fitted with a forklift plug. They can plug into a standard 48v charger, running from the main solar power system’s inverter, or they can plug directly into the solar power system’s battery stack. If not in use, the buggies can each contribute another 10kwh of storage to the system.
The ZERO electric motorcycle would be great in town. Out where I live, with a limited range of maybe 50 miles, I can go the 32 mile round trip to the bank or the barber. I guess that’s fine. It has to plug into AC from the solar power system.
Then there is Sun King, the electric launch. It is solar powered, so it pretty much takes care of itself. I have traveled thousands of miles in this boat! When stored in the shed, there are three panels outside and a dedicated charge controller to keep it fresh. Sun King can serve as a backup power source, with 7.5kwh battery and 5kw inverter aboard. Maybe I should charge the Zero with the launch!
The bike and the buggies are my main concern and there are special considerations with my present system capacity.
First, the plug-in golf car charger and the motorcycle both have something in common with your new Tesla’s 120v charge plug. They connect to a standard outlet and they pretty much suck out as much power as it can give. That means you can’t do much else with that circuit when a vehicle is charging. I have the motorcycle charger on a different circuit from the buggies so they can charge at the same time and only one charger for two buggies. I only have two 120 circuits in the shop, so forget using the air compressor or other big load.
Then there is the capacity of my solar source. Because the motorcycle never completely turns off, I leave it plugged in all the time. However, I have it on a timer, plain old appliance timer, so that it charges only during the day when there is usually plenty of power. But there are cloudy days and, for some reason, that’s when the wife likes to run the clothes dryer. You get the central air, Man Cave a/c and the clothes dryer going on a cloudy day and you may not get the battery bank topped up if charging buggies. So I charge buggies when the sun is out and the dryer is idle.
Another buggy and an electric aircraft are in the works, as is a solar-powered yacht. The yacht project has languished, but when the airplane is finally delivered it will need to be charged. My plan is to park the yacht next to the hangar and get started on the yacht’s power plant. Two birds with one stone. Shared resources. I can’t use both of them at the same time, ya know.
Now what if I broke down and bought an EV or PHEV (Plug-in Hybrid)? Yeah, I’ve thought about that. For MY driving, I’d use the 120v cord. For near errands I would just as soon go on the ebike or the big Honda. My wife, on the other hand, is a goer, but there is a good chance she could get by with the 120 cord. The power rate of the 120 cord would not require major system upgrades, though a few extra panels to help out on cloudy days would be desirable.
If I were still working, I’d have a commute of around 100 miles, daily. I think now we are talking PHEV or going to a faster 240v charger. That’s where it gets tricky, because all of this power is coming from solar panels, batteries and inverters. Either that or there’d be a heckuva power bill.
First, I’d need more power source. As it happens, I am in talks with John Kimball about getting another pallet of solar panels. Batteries? As long as I could charge in the daytime I’d be okay, but most people work day jobs! The extra panels could be arranged to maximize early morning and late afternoon charging and, if I had a 400 mile car it would work out, at least in the summer. In winter, a trip to the Supercharger station might be needed once or twice per week.
Then there is the matter of inverter capacity. As it happens, I have a backup inverter that could supply the 50 amps of 240v to a fast charger. The fast charger would use more power than the house! What does an extra 10-12kw inverter cost? It adds up.
So, yes, I am using solar for vehicle charging and making expansions for the future. As far as a new car goes, I think I will opt for a PHEV. It may be the best of both worlds. A Ford Escape (ugly little car), for example, could make it to Walmart without the engine starting. It would run the engine most of the way home. A trip to the bank or barber would run 100% on sunshine.
–NC
Used Panels?
Junk yards like to say that all cars run on used parts. It is true. The same is true of solar installations. There’s a solar farm being built just up the road and there are 180,000 panels sitting in piles in the field. They are soaking up dust, dirt, rain and humidity while waiting to be mounted. And they’ll work.
What about panels that have been installed and running for 5 years? They are likely to have a slightly reduced output, but they are also very likely to be pretty cheap, compared to new ones. Which is the better deal?
Personally, I have bought new, latest, greatest panels for my boat projects to get the most watts in the limited space available. For my house, though, I have hundreds of used, sometimes abused panels. The last panels I installed were on my ground mount. Not sure how old they are, but they were in service, out in the elements since 2015, and they work great Others, the ones that were literally thrown off the roof when taken out of service, are mostly still running fine.
Good news for folks considering buying used modules, a recent report says that panels made a few years ago were made differently and do not degrade as quickly as the newer panels. Don’t worry, neither is likely to be a problem. The report says the big difference is in the layer of clear sticky stuff between the glass and the silicon. Just like the plastic headlights on cars, enough time in the sun and they start to discolor. The layer in a panel is so thin that you just don’t notice it. Frankly, the solar cells don’t notice it much, either.
After a dry spell, John is once again finding scads of used panels and new-old-stock surplus. Don’t be afraid of them. They’re good, cheap watts.
–Neal
One Moment, Please
I called John to fuss about the website and email. Yeah, there’ve been problems.
In his John’s Blog, you never know what kind of crazy stuff you’ll find, but there’s really useful info, too. He mentioned a recent email blast and I didn’t get one. I live 700 miles from Miami, so it isn’t like I can just drop by and see what specials he has going or what kind of leftovers might be in the back corner of the warehouse. I rely on the emails for that info. If you did not get a recent email from Sun Electronics, do what I did. Go to the main page and sign up anew. Databases get corrupted and stuff just evaporates with computers. Freshen up your listing. John has some really great deals on the way.
Then there is the trying to get the page to come up. You can’t find deals and I can’t write blog if we can’t get in. There has been a problem, lately. I observed the page as to how it did not work and it looks like a DNS problem. When you type in sunelec.com or another site, it calls up the Domain Name Server, or DNS, to see where to go next. If that is broken or a cable is down, you don’t get to the site. If at first you don’t succeed, try, try again. Research Rich, the IT guy du jour, says the signal is bouncing all over the world before it gets where it needs to be. It is being looked into.
IT guys and gals and webmasters at Sun Electronics are like drummers in rock bands. Lots of turnover. I don’t know if they die or just wander off, but the new guy has to figure out what the last guy did or did not do. I have put word in that I want to see more tech details and data sheets.
The phone usually works, though, so give John or Roberto a call if you need anything.
While I was on the line with John, I checked on what inverters he regularly maintains in stock or can get a quick drop ship on. I have been getting questions on setting up a backup or solar hybrid system, with details on what hardware to use. AND I have been wanting to answer those questions with an article with specific hardware that I know will do the job. Watch for that soon…if I can get back into the website.–Neal
It’s That Time Again
Hurricane season had an ominous start this year, though nothing much has come of it, so far. Still….
So what about preps? Generators are a good start. You don’t want to wait until the last minute to find your generator won’t run.
My main backup generator is a diesel. Not much problem with diesel and I give it a monthly (more or less) exercise to keep up the battery and equalize the system batteries. Mom’s backup was a Generac natural gas-fired rig, perfect for old ladies. It self-exercised once a week. That’s a bit much, in my opinion. Most folks don’t have a natural gas or diesel generator and the typical gasoline generator can be a lot more fussy.
Mine is fairly typical, with a Honda engine and 6750 watts. It has been stored for a year, full of gas. It started on the first tug of the rope! Let’s look at why.
When I got the machine, it was given to me in non-running condition. Oil leaked out and it wouldn’t start. The oil leak was simply a loose drain plug and a Honda engine has low oil shutdown protection. Then there was the carburetor. The machine had been stored full of regular gas for years, with the fuel valve on. Modern gas is terrible for several reasons. It is ok for running, but not for sitting. The alcohol separates from the gas and causes corrosion. The gas slowly turns to syrup and eventually to a solid. The carburetor needed an overhaul.
Everything was cleaned up. New spark plug. Oil change. Crumbling foam air filter replaced. Good to go.
After the machine was running again, I put on a quieter muffler. The old one was louder than Spinal Tap cranked to 11. I made a cord to tie to the input of my Sunny Island inverter, test ran and then prepped for storage.
The tank was filled with alcohol-free marine gas. Sea Foam fuel stabilizer was added. It was cranked and then the fuel valve was turned off to drain the carburetor. On Hondas, there is a drain screw on the carb that you can use, too. That’s the way it was left. Leaving fuel in the tank is iffy, but this was the good stuff.
When the generator is in constant use, it will run fine on pretty much any gas you can find, as long as it is fresh. Just make sure that if you leave it filled, use only alcohol-free and an additive like Stabil or Sea Foam.
A Honda engine should start on the first or second pull if it is in good shape. Other engines usually are not quite that obliging, but if you feel chest pains coming on while trying to start your generator, it is probably time for a tuneup and maybe even a carb overhaul.
Running a generator for days on end can use a lot of gas that can be hard to find. Not only that, you need to change the oil every 25 or 50 hours. Running the generator on a battery backup power system can be super efficient. It will use a lot less gas, put fewer hours on the engine and let you sleep at night without that constant roar.
Get ready while the weather is calm. Store it completely full of gas to avoid condensation or completely empty to avoid the gas going stale. Leftover gas can be burned in your car. If you don’t have mechanical skills, take it to the shop early. Local shops, here, can take over 2 weeks to get to your engine during mowing season.
–Neal
What Voltage Should My Battery Be?
As a rule, the Direct Current (DC) side of an off-grid or backup home power system will be 12, 24 or 48 volts. Some equipment is available for the archaic 32 volt system and there are maverick higher voltage systems. I think most of you will best be served by one of the big 3 systems because you have better availability of hardware at a better price.
First, let’s understand power. Power is measured in Watts. It is calculated Power= Volts X Amps. For some odd reason, this is expressed in the industry as P=E X I. Go figure.
Ok, so from that formula, to get more Power, you need more Volts or more Amps. More amps will require heavier cable and careful management to prevent losses and meltdowns. It will require bigger batteries or more in parallel. More volts will require more batteries or cells in series to achieve, but you don’t have ridiculous amounts of copper to carry the current.
So, is there a rule of thumb as to which system voltage you should choose? Let me propose one. I like 00 gauge cable. Triple-ought is harder to find terminals for and 4-ought (0000 gauge) is difficult to work. Depending on which chart you use, what the temperature is and how long the cable is, you might see double-ought cable rated from 175 to 283 amps. I lean toward the higher number for solar use because my cables are reasonably short and don’t get much above 100 degrees. Let’s call it at 250 amps for the sake of a discussion.
250 amps X 12 volts = 3kw
250 amps X 24 volts = 6kw
250 amps X 48 volts = 12kw
So here is what I propose: If you need more power than a 00 gauge cable can carry, maybe it is time to step up the voltage.
There are other considerations. Running a 12v system with “12v panels” can be very expensive because the so-called 12v panels are expensive. They are a specialty item, usually targeted to the marine market. If you own a boat, then you know boat stuff is expensive. You can avoid that penalty by using standard 60 or 72 cell panels with outputs in the neighborhood of 40 volts by using an MPPT charge controller. That stands for Maximum Power Point Tracking. Most MPPTs are good for up to 150 volts input, though I have a Midnite Solar controller that can handle 250 volts. Some MPPTs of dubious Asian origin might handle a single 60 cell panel. Read the spec sheet carefully.
With charge controllers, you’ll get back to the P = V X A thing again. Most MPPT charge controllers will automatically adapt to the battery voltage. A 60 amp charge controller is good for 720, 1440, or 2880 watts, depending on battery voltage. If you are shelling out $7-8 hundred bucks for a high quality controller, maybe just stepping up to the next voltage level can save you some big money.
Decisions, decisions.
—Neal
The President’s Analyst
I watched an old movie the other night. Re-watched it, actually. Gee, you’re getting old when you can remember a movie from 1967.
The story revolves around a psychiatrist who is chosen to be the president’s personal shrink. Now, why on earth would Americans elect a president who needs a shrink? Come to think of it, we’ve probably elected a bunch of them who could use a shrink! Or maybe we need an analyst for electing them.
Anyway, the shrink knows all of the prez’s secrets, so every intelligence agency around the world wants to kidnap him. That is, except the American intelligence agency, which wants to kill him. Oh my. In the end, though, it is not the spies that get him. He is captured by the most ruthless and dangerous organization on the planet: TPC, or The Phone Company. This was in 1967, before Google was around.
Nowadays, the phone company, is much diminished. The stock symbol is just “T”. Today, the more hated company may be The Power Company. Boy, I know when Florida Power and Light locally cast off the old Gulf Power name, something went wrong and everybody got the most insane power bills, making the new TPC much reviled. Things have have settled down with them, but around the country there are some real doozies, like MY power co-op.
John and I sometimes have the discussion of whether or not you can justify the cost of solar at home vs. just paying the monthly bill. The answer depends on a lot of factors and often the value of the solar goes beyond the cost per kilowatt-hour (KWH). See, there’s also the security of keeping the lights on when TPC can’t. The big thing is to do it right.
After the big flap with FPL this winter, I see solar panels sprouting up everywhere in the FPL service area. That billing glitch (I think that was the problem) was a bonanza for solar companies. But the solar companies can be scoundrels, too. I have seen them put panels on roofs that can’t get more than 2 hours of sun per day, owing to trees. I have even seen them place panels on the north side of the house!
The biggest solar scoundrels may be the ones who install the wrong kind of systems where TPC is just plain evil, like my co-op.
I will show you what I mean. The published fee structure is that you pay $50 for an application, which they may or may not accept. If they do they will be slow about it. You can’t have more that 25kw, which is not much of a problem. 8kw seems to be pretty normal around here. They will charge you $2.39 per name plate kilowatt of capacity. Every month. You almost never get that much power out, but there it is. You do not settle up on the net difference in what you make and what you use. For every KWH that goes out, you get avoided cost of 3.9 cents. They do not include transmission costs, just generation cost. You pay around 13 cents for every KWH you use. Oh, and you have to maintain an insurance policy in case your power system messes up their power system, like that could actually happen. And if their power system messes up your power system you cannot sue them. Got that?
So let’s do the math. Typical 8kw system X $2.39 = 19.12…you owe them just because you have solar panels. That’s in addition to the $45 base fee, (FPL’s base is much lower) so let’s just round up and call it 65 bucks you owe them before you use or make any watts. In these parts, with sunny days, you can, in theory, make 5 hours of standard solar, or 40 KWH per day, or 1200 KWH for the month. 1200 X 3.9 cents will get you $47 worth of electricity if you never use a single watt. So 65-47 and you still owe TPC 18 bucks. Well, remember, without solar, you’d have started out owing 45. Also remember, you don’t get sunny every day. I have a bunch more than 8kw (nameplate rating) and I got 1180 KWH netted from my system last month when we had a week above 100 degrees.
On the other hand, if you are using those kilowatts, not paying TPC 13 cents, the deal gets a little better. Assume the 3kw a/c is running with 500 watts of miscellaneous loads, or 3.5KW x5 hours, and you get to not buy 17.5 KW. In 30 days that’s not buying 525 KWH. Times 13 cents and you are not paying for $68 worth of kilowatts. That leaves 625 KWH that you sold to TPC for $26. So, together, that is $94 less paid for electricity while paying an extra $19 for the solar connection fee, or a net reduction of $75.
We are talking, in our example, of pretty much what my neighbor EJ has. The monthly payments he makes for his system are $120, so he is in the hole. His system does not have battery, either, so when the hurricane comes, and they always do, he will be in the dark for a few weeks. EJ was sold the wrong system and he is not happy about it. Changing the usage , using more power during the day, will help and he may be able to break even. We’ll see how it does over time.
I have not been able to get EJ to sit down with me and go over his bill, but he claims they are charging him MORE than the $19 published solar fee and giving only A PENNY for the power he sells them. If so, that is really a bad deal and he is legally unable to sue to change that. I don’t know that is a fact, but he seems to think so! I told you TPC is evil!
If he had a hybrid system, depending on how much he uses, he might have been able to make enough to zero out his consumption from TPC and he would not have had to pay the 19 dollar solar fee. He’d still have to pay the $45 base to keep TPC as his backup supply.
My hybrid system made 1180 of the 1280 KWH I used last month. I expect to get a bill for about $58 from TPC. It would be $211 without solar. Because I put my system together myself and paid as I went, there are no monthly costs, beyond a little distilled water for the battery and a little diesel to exercise the backup generator. Overall cost of the system? I have no idea. I don’t keep records so I can have plausible deniability with the wife. Besides, I’ve had a lot of fun doing all this stuff.
–Neal
That Black Box
What’s that black box on the back of most solar panels? Is it just a place for the wires to come out?
There are all kinds of panels, but the usual 60 or 72 cell module in an aluminum frame is going to have the black box. This is usually called the junction box. Yes, it is a handy way of getting the power out of the panel, but there is more to it.
If you have just a laminate, which John sometimes has in stock, you have the glass panel, but not the aluminum frame or the junction box. The back of the panel has a number of silver metal strips protruding and they are kind of delicate. You don’t have just a positive and a negative. Terminals inside the black box clip onto the silver strips and then the box is glued to the panel with silicone. Silicone helps keep the water out, too.
The typical panel has not one, but THREE series circuits of cells in it. There’s good reason for that. Poly or mono cells can be shut down by a single large leaf or bird splat. Sad but true. You don’t want your rooftop solar to shut down because the chimney is putting a little shadow on one of the panels do you? Of course not. So, they put three circuits in there, hoping you only lose a little power if you get a little shade.
Inside the box, there are some diodes. These are like one way valves for electricity.. They won’t let power flow backwards, but if a string within a panel is blocked or if the entire panel is blocked, power from other panels in series can use the diodes to work around the panel that can’t work and let the other panels in a string get some work done.
Usually these are not a maintenance item, but things happen. Lightning can burn out a diode. Heat can get them, too. Once in a while, like on the old solar shingles on my shed, somebody makes some poor choices and undersized diodes are used. A bad diode can cause hot spots and eventual panel failure. If you ever notice that one cell in a panel is brown or unusually hot, shut it down before it breaks. It probably has a bad diode. Fortunately, this rarely happens.
Crazy things can happen, though. I was once given a panel that had gotten too close to a tractor with a front loader bucket. (Actually, I think it was the other way around.) The story goes that the panel, fearing for its safety, leapt from the rack to the ground. In doing so, it left the cables and junction box behind. That left four shiny strips on the back of the panel. I could have just bought a new junction box. I don’t know if John has them, but numerous people sell them online on ebay. It seemed rather pointless as the glass was broken and the panel was bent, so I just soldered on some diodes that I had in the parts bin. This was not going to be installed in a system. Not even I would do something that appalling. What I did was probably worse. John and I had been having this discussion on how hard it is to destroy a solar panel. The cells, after all, are just finely sliced rocks with wires attached. He advanced the notion that you could probably punch holes in them and they’d still work.
So why not try it? There are neighborhoods in Miami where gunfire is not uncommon, but it is generally frowned upon. Not so in my neighborhood, so I got to have the fun. I proceeded to make small holes with a .45 pistol and large holes with a 12 gauge shotgun. While the power is somewhat reduced, it will still charge a battery!
It may seem that I have digressed, but back to the point of diodes in the junction box, the diodes I had tacked back onto the panel allowed the working and non working sections to work it out so that panel still had enough output to charge a battery or operate a car running light.
I am pretty sure that a shotgun blast directly into the junction box would be the end of the panel. Don’t try this at home.
And, yes, the junction box IS a handy place for the wires come out. Take note when ordering what kind of connectors are back there. MC4 is the “usual” but there are others that look similar, but won’t fit, or will fit, but not well enough for a safe connection. Be sure to order the right connectors so you won’t have the installation delayed. You don’t want the neighbors to hear you cussin’.
—Neal
Combining
Where I live, you use the word combining, the emphasis will be on the first syllable and folks’ll think you are harvesting the crops. In solar, the emphasis is on the second syllable and we are talking about connecting solar panels in parallel.
If you read my Tuneup post, you know that I have been working to squeeze all the watts I can from my system. We are expecting about 5 hours above 100 degrees out, today, and the rest of the week will be hotter. The a/c units are going constantly. The heat causes us to use more laundry, a lot more, and my wife never mastered the concept of the clothesline, so the dryer is doing a load or two a day. We are using a lot of electricity. Last month, we used only 15kwh from the grid and I’d like to keep it that way.
One of the areas I needed to attack was the fact that 2 banks of panels on the Solar Shed were dead and one was weak. These are banks of 21 panels putting out 7v each. They are arranged in series, going down 11 and coming back 10. To maintain symmetry, there’s a spare panel at the end, so 22 panels in each cluster. Why waste a panel for symmetry? Understand that these were discarded, recalled panels. Each had been thrown down from the original roof and each had a size 11 boot print on it. Not prime hardware, but they make a good roof. I figured I might need a few spares and I was right.
Each block of 21 panels puts out around 140volts and 700 watts on a good day. (150 volts is the input limit for most charge controllers) The first block is 1A and goes to a double pole knife switch in my control room. The other side of the double pole switch is connected to 1B. Another switch is connected to blocks 1C and 1D. The switch outputs go through 4 fuse blocks and on to charge controller #1. Charge controllers 2, 3, and 4 have pretty much the same setup. The cables are all marked to match. Troubleshooting a bank, I watch the meter and pull one of the switches. If with one switch off the meter shows half the power being produced, then things are ok. I can pop all the fuse blocks open and then reconnect them one at a time. The power from each group should be pretty close. This is not using a factory-made combiner because this is a bigger system than most of those are made for, but it is a combiner all the same.
With this ease of troubleshooting, it was clear that blocks 2B and 2C were stone dead. They would be the 6th and 7th blocks, so I went out and took a look at the roof. Block one is the lower right corner. Two rows of 11 to a block, you remember. There are 14 rows, so the top 4 rows are blocks 2B and 2C. I instantly realize why I haven’t fixed the problem sooner and why those two rows failed. Those were the last rows I put up, using the worst of the solar shingles I had and it is HOT up there. Typical temperature up there is 140 degrees. I’ve measured it.
You can’t very well troubleshoot solar panels at night, can you? And you can’t climb around in the attic very long at 140 degrees. Rain was the answer. We got a pop up shower, cooling things a little and I popped up into the rafters with a meter and tools. Testing the panels was easy enough, but getting around up there was not. I was careful not to rain down boxes of junk onto my shiny motorcycle. I was more concerned about my scooter than falling myself, which could have been a bad thing, too. I found 3 dead panels and 2 more that had been bypassed on a previous trip up there. These panels have 2 weaknesses. They can get water inside that corrode the little silver wires and they have inadequate diodes. I don’t know what got these panels, I just cut the wires and installed bypass cables. At the ends of the rows I found one spare panel that I could plug in. Why not just replace the panels? These are overlapping shingles and you can’t just pull one out at random. Even near the top, I would have had to pull off dozens just to get at the few bad ones. The older I get the less I enjoy working on roofs, so forget that.
I was running out of daylight and supper was calling, so I did a quick check with the switches and fuses and saw that all banks were live, but I did not have anywhere near the extra power I wanted. I felt I knew the answer, but supper called and I needed daylight to go further.
Next day, I went out and observed the gains each bank gave as they were enabled. The repaired block 2B was pretty good, but 2C only gave around an extra 100 watts in the total. Checking each bank’s voltage offline, 2C had the lowest voltage.
So what’s the problem here? All banks in a combiner joining panels in parallel need to be pretty closely matched for voltage. It does not matter if block 1 is 1000 watts and block 2 is 500 watts, if you want to get 1500 watts from the combined 2 blocks they need to be the same voltage. If you parallel a 72 cell panel and a 60 cell panel you will have a voltage mismatch and when the MPPT charge controller starts loading down the big panel, it might not even bring the voltage down to the point where the smaller panel is contributing a thing. If you have some mismatched panels, best to put the one kind on one charge controller and the other kind on another controller. Sorry, but that’s just the way it is.
So back to my personal problems, my foray into the attic picked up a few hundred more watts instead of 1400 watts, but with all of those bypassed panels up there, I need to figure how many more spare panels I need to locate and incorporate into which string of panels. The extras for those rows are already gone, so I need to make some longer jumper cables, I suspect, to reach unused panels in other rows. An alternate method would be to disable a panel or two on the two good blocks, lowering their series voltages. Oddly enough, by taking maybe 2 panels or 68 watts out of service, I could enable as much as another 1000 watts!
So, in case you missed the lesson of this parable, the voltages of each single panel in parallel or each series string needs to be pretty close to the same for best power output. A volt or 2 won’t matter, but 10 or 20 volts can make a huge difference.
If we can get a cool enough day for me to get back up there I will let you know how things end up here. We’ll talk about mixing and matching panels in series another time.
—Neal
Time for a Tune Up
I have been off grid for a while. Mostly. Things are great when the sun shines, but it doesn’t shine every day. The next 9 days are forecasting rain, in fact.
Last night I came out to the cave and discovered the batteries were down to nearly 50%. Uh oh. If you want lead acid batteries to have a long, productive life you don’t go below 50%. It seems that SHE-Who-Pays-No-Attention-To-My-Edicts ran the clothes dryer on cloudy days, twice in a row. Hoo boy.
So, I flipped the switches back to the grid. Not everything goes back to the grid. The three a/c units are hard wired to the solar system, so on THIS rainy day, the batteries were not exactly overflowing with kilowatts. I like to exercise the generator once a month, so as I write this, the Kubota is buzzing merrily outside.
The Sunny Island inverters, which try to run everything, also like to equalize the batteries every month and that takes hours of generator time, which translates to a lot of Diesel. Have you priced Diesel lately? I have about 600 gallons at last year’s price, but still…I equalize quarterly and do a RUN 1 HOUR command monthly.
In the meantime, there are two ways to avoid flipping the switch back to the grid: Use less or make more. Have you noticed that human nature does not want to let you give up anything you’ve had? That leaves the choice of make more.
The aforementioned SHE has suggested that I make the Man Cave larger. A gift from heaven or, as a friend has suggested, perhaps she just wants me out of the house without the expense of a divorce. Either way, that would give me more roof space for more solar shingles. Granted, that would be more north-facing roof, but that does not seem to matter a lot in the summer when I need it. Lumber prices are dropping, too, so I am drawing up my bill of materials.
In the meantime, what about a tuneup to get at all I’ve got? The west bank is easy to keep clean, as is the lean-to bank. Moving the lean-to bank to a somewhat easterly ground mount would perk things up, but the big oak is not completely down yet. The Solar Shed shingles seem to have come with a permagrunge. I will invest in a new long window washer/ motorhome scrubber and see how that works out. Clean panels are productive panels.
But there’s more. In taking down the Zero Export Grid Tie experiment, that left 2 kw of panels off line. It took a couple of tries to get them running and they are a big help. I need to update and nail to the wall a system diagram to better keep up with where each of around 400 panels is connected.
Then there was simply resetting the charge controllers. I don’t know if they got addled by a nearby lightning strike transient, but a couple picked up some watts after turning them off and back on. One of them was hundreds of watts better.
Finally, my setup allows me to easily isolate individual strings for evaluation. I discovered that two are stone dead and one is, shall we say, relaxed. That’s nearly 3 kw out of service and that would be handy when the sun comes out between showers. There could be some corroded MC3 connectors, but the most likely issue is blown diodes on a couple of panels in the dead strings. I built the arrays with extra, unused shingles, so after finding the offenders, it is quick to insert a jumper cable and get things running again. On the wimpy string, I am betting on good diodes and a couple of dead panels. Getting that extra 3 kw back will be great. Maybe I won’t have to throw that switch back to the grid next month.
My RUN 1 HOUR is up. Time to go check if the Sunny Island is going to try to hijack the genset. In the meantime, try to consider if a tuneup might help your system.
–Neal
John’s Rants
John’s ranting about the shortage and price of solar modules over on his blog. He can get pretty entertaining at times, but he is also very serious. This guy wants everybody to have a roof or backyard full of solar panels.
I find it amazing that the government creates a full tilt initiative to promote solar and then puts all kinds of roadblocks in the way. It must be working to some degree. We know solar farms are going up everywhere, but even in the home and DIY market, it is getting harder to find 24 and 48v system hardware. Closing down reliable coal and nuke plants before the solar farms are running all get battery assistance is really dumb, especially with electric cars being forced upon us.
Then, once people adopt solar, they find the .gov or the power company has put some limitation in the way. California now requires every new home to have solar, but they have been promoting a rate structure that would eliminate solar. In the meantime, people in California need solar to keep the lights on, because the power company can’t seem to do so.
Good news on that front, a judge just ruled that Arkansas power companies must go with net metering and pay homeowners full retail for their excess power. Even better, no solar connection fees.
There is also potentially good news on the solar panel front. The industry notes that many solar farms will be repowering soon. The hitch is, THEY have to find some new solar panels. Nothing wrong with second hand solar. I have over 300 of them, 15 years old, out on the Solar Shed and my house is off the grid. These were not even pampered like farm solar panels. These were stomped on and thrown off the roof.
When John sells used, they are tested and graded by appearance and you get a warranty. It may soon get better than that. So many panels could be coming to market that there will be new uniform standards for grading. For example, today’s panels are made with higher dielectric ratings (how high a system voltage you can run without you getting electrocuted ) Early grid tie strings would run up 300 to 600 volts and now the commercial farms can run over 1000. That’s good to know if you put together a grid tie system with a new inverter and used panels. (Unless you live in Arkansas, grid tie may not be a good idea.) I think the rest of it is pretty much what John has done for years.
Anyway, we may see cheap panels return IF the solar farms can get new panels. The used panels will not be these 400+ watt super modules, they’ll be the 250 watt modules. No problem, you pay by the watt and not very much. Just use more. Those 300+ solar shingles at the Solar Shed are only 34 watts each on a good day, but they add up to some serious kilowatts.
Now, if we could only get rid of a couple of dozen government agencies that nitpick us to death! Seems like I recall that in Biblical times they’d have a Jubilee. Every 50 years, everything would get reset. That’d be great. Congress can crank out a lot of laws and regulations in 50 years, but at least they would not pile up on the previous ones.
In the meantime, let’s get John outfitted with new boots and fedora. Send him out to search the land for more panel bargains.–Neal
There’s An App for That
In early summer of 2015, I was on my solar expedition launch Sun King. Cruising up the Tennesee-Tombigbee Waterway. It was raining and getting dark as I approached the lock and dam at Aberdeen, Mississippi. I don’t like to run in the rain and there are limitations to running in the dark in a solar-powered boat. Nonetheless, I pressed on. I had a rendezvous the next day. An important one. My wife and Mom were bringing supplies to restock my chips and jerky rations.
Getting through the lock was no big deal, but it was raining pretty well by the time I cleared. I turned to starboard and went looking for the channel markers to the Aberdeen marina. It turns out the LED floodlight was inadequate and the rain made it impossible to find the way. It is tricky in good weather if you are a stranger. I found a shallow spot and dropped anchor for the night. After supper, I heard a power boat go by. Local river rats always know the way.
It was a good thing I locked through when I did. By morning, the river was up 20 feet and the current was faster than my boat. Man, it had really rained. It was still gloomy, but after breakfast and coffee I wound my way through the channel and found the marina. It was still a little wet, so I tied up at the seawall to wait before checking in with the folks who ran the place. Note that despite running in the dark, fixing supper, fixing breakfast and getting underway in the gloom of a rainy morning, I still had plenty of power.
Tech specs: 1620 watts of solar panels, 6x Energizer 8v golf car batteries, arranged series-parallel for 350 ah at 24vdc. 8 kw inverter (overkill, but the 3kw I had before had died). Motor was a custom build, based on an array of Minn-Kota parts.
It would be a while before the resupply crew would arrive, so I reclined my captain’s chair and settled back for a little snooze. It had been an unsettling night with all the thunder and lightning going on. My nap didn’t last long as suddenly the gawdawfulest blast of catterwallin’ occurred and just kept on.
Mississippi has a network of storm sirens throughout the land. You can hear them for miles and if you are between them they set up something of an echo. I had tied up right under one of these infernal devices. What a rude awakening!
I survived that day at Aberdeen and the various perils of the entire 1920 miles of the trip around the big island of Mississippi. Bet you didn’t know Mississippi was an island did you? If you can drive a boat around it it is and I did so. So it must be an island.
Yesterday morning I had a jarring awakening. My phone has somehow developed the ability to be the equivalent of a Mississippi tornado siren. It doesn’t matter what the volume settings are on the phone, this makes itself heard. Yup, tornadoes inbound. I checked the radar and saw it was doing the usual split up the river that is our county line and the other river that is our state line. I don’t know why, but the tornadoes like the river valleys better than our ridge. I’m ok with that and I rolled over to catch some more zzzzs, while Pensacola got thrashed.
Later I got to thinking about phone apps that might be useful for solar. Since I have gone fully off grid, the days of endless gloom and rain have begun. I have been going through some neglected areas of my system to try to squeeze out a few more watts.
At the planning stage, I found Suncalc which shows the sun angles at different times of day and in different seasons. If you can’t site your solar panels to the traditional south orientation, Suncalc might help you find a good alternative.
At the building phase, there is a app that lets you use your phone as a level or clinometer. Note that not all phones have a sensor array. I hold on to old Androids to use as tools if they have sensors my regular phone does not. If you can play video games by tilting the phone, you have the sensors that will let you mount your supports vertical and horizontal and then set the panel angles.
Some phones have a magnetic sensor that will drive a compass app to select your direction of the array. If you don’t have that, some compass programs will work with the GPS in your phone if you walk around a little.
There are also a number of apps to predict your solar insolation or available sun power. Some are purely theoretical and some are somewhat interactive. Solar Radiation Calculator decided that at my location I should receive 2920 kwh per year, per square meter, from the sun. Given that panels in perfect alignment are good for around 20% efficiency, I need a number of square meters. That one is probably best for the planning phase. Another app i tried, PV Solar Forecast, scans weather service radar and cloud maps to guess how many watts your system will give you. I am still learning this, but it looks like it is assuming you have a grid tie system. There are some calibrations available, so this one might be useful for rough estimates of the day’s performance.
Now, for even more accurate info, you will find there are apps that will talk to your charge controllers, inverters or grid tie system to get the direct scoop on things. There are even aftermarket wattmeters that your phone can monitor with Bluetooth.
Try roaming the Apple and Play stores for apps. Usually, there are free ones you can try. These often come with reduced features and annoying ads. If you find an app you really like, paying a very few dollars can make those ads go away and bring you some new features.
Let’s see now, earlier, the app said I was making 400 watts. says I have perked up to 1.6 kw, and by the end of the day as the rain clears I’ll still have clouds and low output. Not a good solar day, but I already sort of knew that. Looks like tomorrow will be better. Good, my batteries need those kilowatts.
—Neal
Firmware Update and New Capabilities
Back when I worked for a living, I was the hardware guy and my partner was the software guy. Tom and I would get together and spec out a new product. I would design and build the circuit board, then hand it off to him to program in the features. Knowing each other well, it worked well.
Back when I was doing field service, I did not intimately know the hardware that someone else designed and neither did the programmers. There was always the tendency of one side to blame the other when something peculiar was happening. Oh, smoking circuit board or howling hard drive was clearly mine and a lot of flashing lights and blank screens after a software update was pretty much a ball in the programmer’s court. Then there is the tricky stuff and suspicion builds.
Today, pretty much everything from your microwave oven to your inverter has a microprocessor in it and things like this have a variation of programming in there called firmware. Some are not as firm as others as you’ll find keypads and SD cards or Bluetooth so you can go in and change the program. One of my inverters is dumb as a rock, as far as being programmable goes. It has a couple of jumper for things like choosing 50 Hz or 60 Hz. Other than that it just turns 48 vdc into 240 vac. Nothing more. Simple. The microprocessor just sits there making sine waves.
My pair of 6048 Sunny Island inverters goes the opposite direction. It is programmable up one side and down the other. Flexible. Handy, I guess, but it scares me to death. There are ominous warnings about not pulling out the SD cards. I have changed the programming a bit, but it is doing what I need it to do, so I generally leave it alone.
Cory’s Outback GS8048a pair is another that is highly programmable and it needed programming when we revived it from retirement. We wanted it to work with the grid when we needed it, run on battery and sunshine when we had it and never, ever sell back to the grid, which would bring the white bucket trucks to his driveway.
This involved dire measures…I had to read the book. There was a bundle of stuff in a plastic sleeve on top of the inverter, but it became apparent that something was missing. We got the inverter running for a while, but were not really satisfied with the available operating modes. The full manuals that we downloaded from Outback (no excuses, you can have the manual on your phone) were frustrating in that they described modes and menus that his inverter did not have. This was an older machine, so I reluctantly decided to do a firmware update.
My innate distrust of software people and experience with clunky and unreliable procedures made me hesitant, but I proceeded with caution. First off, I went online to Outback’s Support page and it was a breeze to download the files. The only tricky bit was the Mate3 programming interface. Was it a Mate3 or a Mate3S? Judging from the photo, I thought it was a Mate3S, which proudly displays its programming wheel. The Mate3 does not. Well, it does not unless somebody took off the plastic cover and left it off. I remembered the plastic cover on a shelf and chose Mate3.
The support page recommended updating the Mate3 before updating the inverter. What’s the Mate3? The Outback system has one or more inverters that will invert, if left alone. It also has a communication block so that other Outback goodies, like FlexMax charge controllers, can coordinate their activities. The Mate3 is the master control panel. It is used to set parameters, load update and save backups of the settings.
This one did not have a card, so Cory’s job was to find one. A small one. 2GB cards are hard to find, so I think he ended up with 32GB. I went through a pro photographer stage early in the digital revolution and have lots of smaller cards from the older cameras. Some of the huge cards reportedly won’t work. I copied the downloaded files to two 2GB SD cards, one for the mate and one for the GS8048a. Files go in the root of the card, not in the folder that was downloaded. That was easy enough, but then I worried about whether the inverters were GS8048 or GS8048a. The two models are not the same and not “close enough”. There is no label on the outside. At Cory’s, we popped off the front cover to view the ID plate and it was indeed the “A” variant.
No more excuses. Show time.
To program the Mate3 first, the SD card is plugged into the slot on the side of the Mate3. The top of the card faces away from you. I punched the LOCK button, dialled up the password, and scrolled through menus to an item that was clearly meant to update the Mate3. Punch the GO button in the middle of the dial and it’s off to the races. While it was programming, a small girl in a swim suit came by, carrying a large chicken. The chicken was perfectly content with the free ride. Life as usual, out in the country. It took a little longer than expected, but it was obvious when programming was finished.
Mate card out and inverter card in. Find the inverter update in the menu and press GO. It happens…and then it happens again. There are two inverters stacked in this system and they are programmed sequentially. It happens and the fans all come on as the beast resets itself. Gee, that wasn’t so scary after all!
Now, into the menus to set the parameters. You never know what will be remembered and what will be forgotten. We got red fault lights. Apparently it forgot it could and needed to handle 50 amps of AC input and settled in on 1.7amps. Yeah, like you can do much with that. More button pushing and we had no more flashing lights and lots of amps. Now, to see if the menus included modes in the new manual. They did…and more. There was an even newer version of the manual, which I had not yet read.
We selected the MiniGrid mode, which lets you run on solar and battery when available and switch over at night when our punky battery gives out. Intriguing, was the GridZero mode. I decided to let that one alone until I read up on it.
The big surprise was the huge power draw we observed when the inverters came on line. We don’t have the house connected. The lights in the hangar were on the inverter and so was the camper out back. Some friends have been staying in a camper while hunting for a new house. This has gone on for a while and the power bills have been high. Really high. FPL high. Last visit, before it started getting really warm, I’d see maybe 2500-3500 watts being burned, but today it was between 3500 and 7500. Wow. I have to have the central air and the clothes dryer going for my house to hit 7500 watts. We decided to hold off on switching power to the house, too. All I know is that when the friends get their new house and Cory’s solar is running full time, he is going to see a heckuva drop in his power bill. If he can come up with another 1000ah of battery capacity, the bill will be trivial.
So, back to the manual and this GridZero mode. Did you ever get excited over a firmware update? Me neither, until now. As I read it, in GZ mode, the AC grid power is never disconnected, like it is in the MiniGrid mode and it never switches on when the battery is low. The grid stays connected, but just kind of rides along with the the inverter, stepping in to help, only when needed. What that means is, when the battery is a little low on a cloudy day, if the air conditioner kicks on with its big starting surge, the inverter will not drop out in favor of the grid. The grid just makes up the difference in what the battery can’t do until that surge is past and you get to continue using the stored sunshine power. Furthermore, there is no little blink that you get when the inverter switches power sources in other modes. How cool is that?
In essence, Outback has built in Zero Export Grid Tie and off grid in one package! ZEGT is one of the best tools available for combating the anti-solar policies we see coming from more and more power companies. With GZ mode, you can stay running off grid after a storm, but maximize the available capacity of your batteries.
I LIKE IT! Maybe the software guys aren’t so bad, after all.
–Neal
Pump it Up, With Solar
I told you when I was working on a couple of small solar projects for The Alger-Sullivan Historical Society’s park. We had our Sawmill Day Festival and fundraiser this past week and all went well. The blacksmith shop/mill/tool museum building had its solar-powered lights on for 2 days straight with no issues. The lion’s head fountain, with solar powered pump delighted young and old. The trolley to bring folks to and from the parking area was not available this year, so two solar-powered golf car conversions ran taxi. Solar was a big hit, though few even realized the sun was at work.
I want to ramble on a bit about pumping water. There are plenty of applications for solar water pumping, particularly in agriculture for filling stock tanks. If you are close enough to a line, our power company will connect your service pole and it will cost you over $40 per month whether you use any electricity or not. If you have a big spread, like those in Texas or south Florida, that could add up. Or for that matter, you might need water where there are no power lines. Solar to the rescue. The principles are pretty much the same as my fountain job, just up-sized a bit.
I did not finish the fountain job in its final form. All of the pumps I ordered came in time, but some looked to be of dubious quality. Submersible pump. Is that like the Made in China submersible boat trailer lights I bought? They were submersible, but did not work after they got wet. Anyway, what I had was working well, so I decided to hold off on the final product until I would have time to play.
The first consideration is to find a pump that fits your need. Does it have to go down into a well? Does it suck water from a pond or cistern? How high does it have to lift? How much water does it need to pump in a day? We were just recirculating water, but it had to push up about 6 feet to the release point. Flow rate was not important. A farm stock tank may be drawing water from a well and pushing it up to the surface. That might be 15 feet or it might be 150 feet. The tank might need one thousand gallons a day if you have a herd of thirsty cattle. The one I used on the fountain was more than enough, so I bought a new pump with less capacity AND less power draw. We’ll see how that works.
A solar water pump project at my house does not involve much of a well. It is just a basin that is filled by a natural spring. It then is pumped about 120 feet up the hill to a series of water tanks and to the house. I wanted a solar backup because when the water-powered hydraulic ram pump fails, it always does so when it is cold, wet or I don’t otherwise want to go fix the problem, which is usually minor. The pump currently online is over a hundred years old, so they are generally pretty dependable. My first two electric pumps were submersible well pumps. Made in China, they worked very well until they got wet. After the second one, I caught on and changed the plan. There are some American pumps that cost 6x more that work well, but I had to learn the hard way. Plan B is a variant of a ShurFlo diaphragm pump, but it is not yet installed. In both cases, the pumps were fed with a bank of solar panels with enough power that they would run the pump without batteries. That is sometimes a lot more panels than you’d need with batteries, but I’ll get into that in a minute.
What I am talking about for pumps are DC powered pumps. With brushes. I am starting to see brushless DC pumps and am curious as to how they will work with a variable supply. So far, so good. Using an AC pump is not so good for a number of reasons, which boil down to dollars. A couple of panels and a pump is cheaper than a couple of panels, batteries, inverter and pump. Furthermore, it seems like DC pumps are easier to get started, meaning an AC pump might need an oversized inverter. The only advantage of batteries and, optionally, an AC system is that the pump could run at night. Fine, but it’ll cost you.
Our fountain is in a terrible place for solar, with oak trees all over, but it works! This is partly because the 10 watt motor is powered by a 68 watt source., two 34 watt six volt panels in series. It’ll run in the shade. If you are pumping water in the middle of a pasture, you’ll likely not have to deal with shade, but you will have cloudy days and there is the extra bit needed just to get the pump started. This can be compensated, to a point with more panels, BUT there is a handy little gadget made for just this issue. It is sometimes called a Linear Current Booster or a Solar Pump Controller. They are available on Ebay, Amazon, some solar suppliers and farm stores. But let me explain what they do.
Put a solar panel in the shade on a sunny day, with no load, and then put a meter on the leads to check the voltage. It’ll probably be pretty close to what the label says. Then put a load equal to, say, half the panel rating and you will see the voltage drop WAY down. That would be too wimpy to start the pump. So what you see is a gradually rising current as the sun comes up and when it clears the trees you have full power and the pump runs. Put lots of panels in parallel and it will start sooner, but the Current Booster has a neat trick it does that can save you the price of some extra panels and puts fewer panels in the way of hail, hurricane or vandals AND can make the pump run more.
What it does is it allows weak current from the shaded panel to charge a capacitor, which acts like a small battery, and when it reaches a certain point, the pump gets a burst of energy that gets it started. Running current is usually a lot less and you may get the pump to run continuously, if a bit slower. Otherwise, it will run in bursts. Once the sun is out in full, the pump just runs.
If filling a stock tank for the cattle, or a gravity tank for a cabin, you can just let them overflow or you can put in a float switch to avoid making mud. Another way to avoid making mud is to divert overflow to a garden. By the way, IBC totes make dandy gravity water tanks, mounted on a stand.
If pumping into a pressure tank, you’ll need a pressure cutoff switch, too. This should be obvious, but there is an old mansion of the outskirts of Century, Florida, that used a locomotive as its water reservoir. It was pumped by a water ram, like mine, without any provision for pressure relief or cutoff. The old timers said it was quite a commotion the night that boiler blew up. For more recent examples, I have seen several 80 gallon fiberglass tanks blown up. You have been warned.
In conclusion, you can use solar to pump water for a number of purposes, with minimal equipment and at a great savings over a conventional power company hookup.
–Neal
Solar Laminates?
Every now and then I cruise through John’s inventory to see what he has in stock. Solar panel availability is getting tight around the country, but John always seems to come up with something. Sometimes it is something strange! Like solar laminates. He has them!
What’s a solar laminate? Well, take a look at a PV module, or solar panel, and most often you see an aluminum frame with the glass stuff mounted in there. The back side has a black plastic junction box with wires sticking out. When they are assembling panels, the business end of it is the laminate, the big glass thing. It is called a laminate because there are layers of glass, clear sticky plastic, silicon wafers and more sticky plastic on the back….all laminated into one assembly. You find these sometimes when a maker goes out of business or has to shut down a line before assembly is finished.
What can you do with them? You can put a junction box on the back and then get creative as to how to mount it. You might find some creative way of gluing it to the roof of your motor home. Maybe get some of the clamps they use with the First Solar thin film panels, which are a lot like laminates. Or you can use the polycarbonate channel used to hold glass in greenhouses.
I have told before of an encounter I had with laminates, but since John has some in stock, I’ll tell it again. First, let me add the disclaimer, “Don’t Try This At Home!”
It started with a call from my friend Courtney. That’s always trouble. It has been so since kindergarten. Anyway, he’d acquired a bunch of laminates, because they were cheaper than regular panels. That’s key with him. He has plenty of money…because he doesn’t spend much. He was going to use them to cover his pergola, his backyard cookout refuge. OK, that sounds good, but his pergola was arched. Courtney said the salesman told him the laminates were flexible, so he was going to bend them over the arch!
Wait just a minute. My Chevrolet is flexible, too, but that doesn’t mean something bad won’t happen if I run a stop sign. Sure, glass is a little flexible, but bending it on purpose? I had my concerns, but I got in the truck and off I went to South Carolina.
By the time I got there, he had come up with some purple wood from South America that we milled into bows to go over top of the pergola. The stuff is supposed to never rot. It was so stiff it was actually harder to bend than the glass.
I spent an afternoon attaching junction boxes. Thin strips come out the back of the laminate and these clamp into terminals in the box. The box is glued to the back with silicone sealer. Using a little silicone is fairly neat, but after the first dozen it is getting messy and you wish you were doing something else. Around Courtney, though, be careful what you wish for.
We used polycarbonate greenhouse channel, wood screws and every stainless steel fender washer the local Ace Hardware could dig up. We’d slip on the channel, bend everything down to the bows and put in the screws. Every time, I just knew that panel was going to explode and spray glass shards in my phase, but they never did.
I forget the final count, looks like maybe 18 laminates, fed into a dual channel Sunny Boy grid tie inverter, a disconnect and a new meter. South Carolina had a great grid tie rate and solar subsidy plan in which the total system cost ended up being pretty much zero, if you don’t count all the time doing paperwork. As a bonus, he could now stay dry when grilling on a rainy day.
The upshot is that solar laminates can be good cheap fun if you are fearless. Or a little crazy. And if 2 old guys can take on a project like this, what’s your excuse? Hmm?
–Neal
EJ’s Solar Dilemma
Florida’s governor just vetoed a bill that would have made solar a really stupid choice, at least with grid tie. The bill had been watered down a good bit, but it was still very much anti solar. A similar, but much worse, proposal is still up in the air for California and there are bad deals all over the country.
Just this morning I read a story of folks in Mississippi who spent a bunch of money on solar, with government encouragement, only to find there was little or no money saved. We have a local example with EJ, my neighbor.
As I have mentioned before, we are on a power co-op, supposedly run by the members. Instead, it is run by a small group, it does not have to abide by Public Service Commission laws and it has managed to immunize itself from lawsuits by its members. This is a recipe for trouble and troubles we have.
EJ was sold a tidy little system of just over 8kw, with 16 panels on the east roof and 16 more on the west. Conventional wisdom would have them facing south, but that can’t happen with EJ’s house. Besides, east-west actually works great!
The house is an older one of cinder block construction, which was a popular building choice in the past, but not very energy efficient. Cooking and hot water are gas. Since moving in, he has taken countermeasures to improve the energy efficiency, including windows, roof and siding upgrades. All well and good, but the bills still go up. The silver-tongued salesman announced that solar was the solution.
In some places, most any kind of solar solution will do, but most places, grid tie is not ideal. In our area, grid tie is a really bad idea and after EJ signed the contract it only got worse. Here’s the deal. He pays $120 per month to the solar financier for pretty much forever, given his age. Solar power offsets his daylight loads and excess is bought by the power company. Sounds ok, right? Wait, there’s more.
In some areas, the difference between what you make and what you use is the basis for billing. In a few places, the power company will pay the same as what they bill you for every KWH and that is a very good deal. One fellow we’ve mentioned in this blog actually runs at a profit in Texas and one in South Carolina pretty much broke even. Usually, though, the power company will pay less than what they charge, but still on a net difference. Not so, here, and there have been other recent changes, since EJ got the installation. Our co-op tallies every outgoing kilowatt-hour for payment and every incoming KWH separately. Worse, they pay only a penny per KWH while charging much more.
Bad, huh? On top of that they charge a steep fee for the solar connection. The fee seems to be based on capacity, as neighbor Brad says he pays an extra 80 bucks for his big system and EJ says his is $40. The co-op finally connected his solar at a time that really accentuates the issue. In the February to April time frame we have overall temperatures that do not require much a/c or heat. So EJ sees a credit that might buy him lunch at Denny’s…if he has an AARP card. That is much smaller than the extra $40 he is charged for the privilege of donating power to the company. Oh, and there’s the $120 he pays the solar company. It is pretty clear to see that solar is not saving him money.
What to do about it? EJ was blaming the solar company for his dilemma. They are partly to blame, yes, but the power company changed the rules between the time the panels arrive and the time they were finally turned on. Where I blame most solar companies is in concentrating on straight grid tie.
Can anything be done to fix this? Let’s see. First of all, the situation will improve when the weather gets hot. We’re having temperatures in the mid 80s, now, so a/c units are being run a little. Come summer, temps will be in the 90s or higher during the day and about 80 at night. The a/c will really be buzzing, especially at EJ’s, because he likes to keep it at 72 degrees. The solar will completely offset his daytime a/c, but won’t help a bit at night, when he likes it cooler. I suggested using a programmable thermostat to just ice down the house during the solar hours and back off at night, compensating with the ceiling fan in the bedroom. That is going to be his best bet.
An energy audit is in order, too. You don’t have to call in a pro for that. You can get plenty of DIY advice on that online. Where I suggest he look is at his 3 refrigerators, checking that they are in good working order and not set excessively cold. A Kill-A-Watt or other portable power meter is helpful in this. Also, it seems he leaves his shop lights on most of the time. Swapping out the fluorescents for LEDs will help.
I don’t know all of the details on his system–EJ is kind of private–but I have learned some details. The grid tie was installed in what may be the worst possible for modification. Instead of a master inverter in the utility room, each panel has its own micro inverter. There is hope in that some microinverters have communication and even islanding provisions. This is of limited value as only a fraction of the panel capacity can be used and every puffy little cloud has the potential to shut it down.
Let me back up a second. A microinverter is a little module that fits behind the solar panel, taking, say, 40 volts from the solar module and connecting it to a 240v power cable. There is no easier way to use solar in your house.
Islanding is the ability to provide that 240 volts to your house to keep the fridge and other loads going even when the power lines are down.
EJ mentions he has an app he can use to monitor production. That’s good, meaning there is a communication controller in the system. Even better, the communication controller may be able to work with a box and sensor coils that could convert his system to Zero Export. With this, he would not be able to sell power back to the grid (there goes lunch at Denney’s), but it would allow him to eliminate the grid tie fees with the power company, saving him that expense.
We’ll watch the situation as the weather gets warmer and see if the audit and modest changes make enough difference to may him happier about the system. If not, we’ll look into what might be done to modify the system at minimum cost.
–Neal
I Pulled the Plug
It has been a long time coming, but I finally pulled the plug on the power co-op. I have long had enough solar power and more than enough inverter power, but battery was lacking and so was buried copper. Then there was the matter of the Round Tuit. I finally got around to it.
Batteries came to me last year. 3000-4000 amp-hours is a good place to be, but for how long? The batteries are strong, but they are about 8 years old. I am hoping for 15 years, but will be ever vigilant for battery opportunities.
There is all kinds of stuff buried in my yard and I am doubtful I can cut another trench without cutting some of the existing pipes and cables, so I sought to repurpose some of what I had. One cable, good for about 100 amps, was bringing DC power into the Zero Export Grid Tie experiment. That had been a successful project, but it just did not go far enough. That freed up the cable, some hardware and 16 golf car batteries.
Ok, remove the 2kw solar feed at the Solar Shed and install a 6 gauge jumper to the AC power bus. That end was done! Now, how to get the power into the house? I do not enjoy crawling under houses or boring holes through walls and floors, so maybe I could use an existing cable. Yes, I could!
Because in an earlier life I was running most of my house on a 5kw inverter, I had installed a lockout so that only one of the two central air units would run at a time. That left a 30 amp line from an external disconnect to the breaker box. With the aid of a very clever mechanism, shown below. I was able to turn my main breaker and that a/c breaker into a transfer switch. All I needed now was a 12′ whip cable to go from the a/c disconnect to the auxiliary power (aka “Generator”) disconnect. Pre-made cables are 6′, so I had to make a trip to Home Depot.
Some of you who are paying attention might note that I only have a 30 amp circuit here. To run the whole house? Nope. Having said that, though, the idea of Code making you put in service capacity of 200 amps and up is overkill.
Another breaker in the main panel has long gone to an “essential services” transfer switch. The load here started out with all the lights and the kitchen. (This was initiated while the house was under construction and a hurricane left the lines down for 4 days. The initial setup was a Trace PS2524 and 8 golf car batteries for backup. No solar.) A few outlets have been added so the TV and other paraphernalia , like a freezer and two more refrigerators can operate. This was all done on a 40 amp circuit, with ease. The two a/c compressors have no connection at all to the house or breaker box, powered directly from the solar shed. Inside, about the only things not on the essential line were the electric range, the air handlers and the laundry room. The only chance of popping the breaker on the new line would come if clothes were in the dryer when the stove was running on all burners. So far, so good. I just have to be careful about asking my wife NOT to cook. If it becomes an issue, I can bore some holes, crawl under the house and pull in a bigger cable.
Another issue to watch in the coming months is inverter capacity. In addition to the house loads, the shop is charging 3 electric vehicles, running power tools and, in the Man Cave, there’s a home theater and more air conditioning. I have two power systems in parallel. A pair of SMA Sunny Island inverters producing 12kw is running the whole house and is the only inverter available to the new transfer switch. Another transfer switch in the Solar Shed lets me connect either the Sunny pair or a homebrew10kw inverter to the essential line. If capacity is an issue, I can run BOTH inverters, one to each circuit, for a total capacity of 22kw. If that should fail, there’s an automatic Kubota diesel generator and a manual Honda generator. The Honda will be living in the space vacated by the old grid tie system. Oh, yeah, and I can always flip back to the grid.
Would I recommend such a screwy setup for you? No. Why do I have such a screwy system? Because it is an accumulation of things that have happened over 30 years, rather than the result of a plan. Capacity increased. Goals expanded. The next phase of work will be to clean it up and make it a bit more conventional.
What I would recommend to most anyone, is to have a transfer switch and generator circuit professionally installed. Make it 50 amps or better. That makes it easy to connect a conventional generator or your new and ever growing solar generator.
Something you need to do if you have solar or a generator is to make use of safety placards. The fire department does not like to spray water on a house full of live electrical conductors. I made some up with a home printer. You can get decal paper or use regular paper and weatherproof it by spraying with clear coat. Something like “House is Equipped With Automatic SILENT Backup Power Generator, Pull Disconnect Around Corner on Generator Shed.” is appropriate for my house.
Two weeks in, I have not needed to reconnect or use the generator. There are compromises in how we operate, such as charging vehicles and drying clothes only during the daytime, but things are going well. I’ll write another time on compromises and you’ll see some of that in other articles, as well.
–Neal
Lowering Brad’s Power Bill
27 kw of solar panels, 3Tesla Powerwalls and a power bill still over $300. What went wrong?
We are at a weird time of year when we are using very little heating or a/c, if any. Bills are usually low. Brad’s have never been low. First of all, the power company changed the rules. They added a bump in the basic fee for grid-tie. Second, they lowered the pay rate. He has a basic rate of $80, plus numerous taxes, and they only paid him around $13 for his excess power. This is happening all over the country, folks. Still, the bill was “only” $378 that time. It has been as much as a thousand. The pricey Powerwall batteries are not very big, but they really help.
Part of the problem is the “facility”. When I moved here, the house was a simple A-frame affair, owned by a retired Naval officer named Les. Chuck then bought the place and turned it into a facility for his corporate entertaining. Many was the time I heard live bands and fireworks, but did Chuck invite me over? I never actually met the guy. Then came Brad. He wanted a place he could raise animals and the place had plenty of room. Sure, there was more than he and his roommate need, but it is a great place, with rolling acres and fishponds. The power bill was absolutely sensational, averaging around $800 per month. What the heck?
I said that Chuck had enlarged the place and outfitted it for entertaining. In addition to the main house, which is probably 3 bedrooms, there is the pool, the smokehouse, the boat house and the garage. The 5 car garage also sports 3 bedrooms, a banquet hall, a gym, an office and, and, and. There are multiple bars and kitchens, sporting at least 6 refrigerators and 2 freezers. Yeah, you could host a heckuva party. To tame the temperature, there are 5 central air systems plus a window a/c in the office.
Start adding that up and you could see why there might be a big power bill. Here’s the thing, the last time I visited, Brad’s phone app indicated a continuous load of around 4kw. The kitchen uses gas, so food prep was not an issue. Water heater is gas. Nobody was doing dishes or laundry. None of the heat pumps were running. A PC and the window unit were running in the office. The pool pump was running. 4kw? My place runs about a tenth of that.
First thing I noted was that the timer on the pool pump was broken and the motor was running continuousely. 1kw. That leaves 3kw. I suggested to Brad that he buy a Kill-a-Watt meter to check those fridges. Alternatively, he could watch his app and start flipping breakers to see where the power was going.
I would just about bet that one or more of the refrigerators or freezers has a bad defrost circuit. Many years ago, when rates were cheaper, I had 2 different fridges with bad defrost and either could add $70 to the power bill. They’ll either freeze up and run all the time, which isn’t too bad, or the defrost heater and the compressor both run all the time. That”ll really get you. Also likely, the thermostats could be set wrong.
My recommendations:
Fix the pool pump. Set it to run only during the day to use up that grid tie power. Daytime is the only time the sun is trying to turn the pool green, anyway.
Check all of the refrigerators and freezers for proper operation and temperature. I recently bought a 3 pack of fridge thermometers to keep track of my fridges for about 10 bucks. (I don’t know any country folk with one fridge.)
Get a programmable thermostat for each of the heat pumps. Disable the “Emergency Heat” coils. During cooling season, run the temperature way cool during the day and back off at night. During heating season, run it very warm during the day and back off at night. Thermal mass of the house can store some of that temperature. The battery will last longer during the night before switching to grid power.
Call the solar guy and have him turn OFF the SELL or GRID-TIE Function and then call the power company to tell them you don’t want to pay them to take your electricity anymore.
Brad will save on heating, cooling, pool pumping and the $80 grid tie fee. I’ll let you know when he gets everything done. If he still is using too much power, he can add more battery.
–Neal
Beware of Solar Sales Pitches and the Whims of Your Power Company
Two of my neighbors got solar power systems. They were completely different setups and the results were very different. Neither neighbor is very happy about his situation.
Brad’s system is BIG. 27kw, with 3 Tesla Powerwalls and a propane generator for backup. The modules are all facing west, because of trees on the neighboring property. It is a hybrid grid-tie system, meaning sun power fills up the batteries, runs the house and then any left over goes to the grid. At night, the batteries keep the lights on until the battery bank gets punky and then switches to grid. It knocked about $500 a month off his bill, but his last bill was $378. Spend $120,000 on a system and you are thinking the power bill is gonna go away. Maybe not. The power company gave him only $13 for his excess power and billed a bunch for the connection.
Then there’s EJ. His is a straight grid tie system, 8+Kw. 16 panels to the east and 16 more to the west. Each panel has its own microinverter, so there is no master panel with a big inverter. Just a breaker. This is a super simple way of doing a system, though I think a master inverter is cheaper and, depending on model, may offer other options. EJ isn’t sure if his bill went up or down. Usage is hard to gauge this time of year in our area. He suspects his bill is up.
What went wrong?
Salesmen may not outright lie to you…not always…but they will always give you the good points and might overlook the negatives. Then, sometimes, the rules change. I think that happened here.
Brad’s system got turned on 16 months ago. He noticed the rule change and the bump in his bill. EJ’s system got turned on just as the new rule went into effect. Brad says he is being charged $80 a month just for the use of the grid tie. It did not look that much to me and EJ says he did not think it was that much, but he agrees that he is being charged for the privilege of sending power to the power company. To add insult to injury, the billing is not based on the net difference between what he consumes and what he exports. They give him a penny for every kilowatt-hour he sends out and then he has to pay around 12 cents to get it back at night. The net result is that EJ may actually have a higher bill with solar than without.
Our power company is not under the Florida Public Service Commission regs, so we generally get a raw deal. The PSC recently tried to enact regs very similar to our co-op’s, but ended up with a phased in change for existing grid-tie users. New users get screwed. This is happening all over the country, with California simultaneously mandating solar and making it a ridiculous choice. There are ways my neighbors can improve their situations.
In Brad’s case, he can call his solar company and have them turn off grid export. Next, call the power company and tell them where they can put their grid-tie meter (on the big white truck). Any excess power will be wasted, but he will not have the grid-tie fee, which is higher than his production. If he gets a few bucks ahead he can add more Powerwalls. The more battery he has, the closer he will be to 24/7 on sun power. There’s more, too.
EJ has more of a disadvantage. There is a good chance that his microinverters are compatible with a communication controller. Heck, it may already have one. I don’t know because he has a dog that would really like to chew on me and two more that would probably bow to peer pressure and join him. Anyway, some of these communications controllers can be fitted with sensor coils in the main breaker panel to prevent export. He could then tell the power company to shove that grid-tie meter back on the big white truck. Changing a few habits like doing the power chores like a/c and clothes drying and baking during the sunlit hours would offset the power company input by a lot AND he’d be rid of the extra fees. Getting into battery storage would be tricky and likely involve a good bit of expense. The most effective change would be to ditch the microinverters and add batteries and a hybrid inverter. Unfortunately, that would cost a bunch and add to the $120/month he is paying for the hardware he has.
Both of these guys have another problem with their bills. They use too much power. Seriously, something is wrong. We are looking into that and I will report on that investigation and the progress they make.
–Neal
Solar Blacksmith Shop?
One of our museum buildings needed power. Solar was the right choice.
I am a trustee of The Alger-Sullivan Historical Society. We formed to preserve the memories of the sawmill heritage of the town of Century, Florida. We started with stories. And more stories. We discovered Indian and Spanish colonial history in addition to the sawmill era. History is interesting when it happened here! Then we acquired property. Then artifacts just started showing up. Our first museum building was the town’s first free-standing Post Office. People would leave stuff on the porch and we added it to the collection. Over time, through generous donations of labor and money, we added a house, a garden, a steam train and the blacksmith shop.
Wiring of the complex kind of just grew…and got destroyed. During our Sawmill Day festival , our big fundraiser, vendors would sometimes drive overly long tent stakes to hold down their shelters. They hit multiple powerlines in multiple places and got the waterline to the fountain. No power to the storage building. No power to the railroad museum in the boxcar. No water or power to the lion’s head. I have no idea why nobody got shocked. Old Neal got tired of hand digging trenches (a power trencher would probably find more stuff to break) and stuffing conduit with stiff cable.
John Kimble, Sun Electronics’ El Hefe, and I sometimes have a conversation about whether solar power is cost effective. The answer is, “Depends.” Lots of variables. In this case, it was a no-brainer. Clearly, a direct power line to the building that displays a blacksmith shop and gristmills would be imperiled with the threat of impalement. Then there is the added cost of routing the line along brick walls and walks to avoid damage. Oh, and the issue of finding a volunteer to dig the trench. I think I am the 3rd youngest member of the outfit at age 68. Nope, there is no money to hire it.
So solar it was. The volunteers from the Lions Club and Bondurant’s Hardware who built the structure included standard AC (alternating current) wiring before the walls got closed up. At least I THINK it was them who wired it. Sometimes stuff just gets done and nobody’ll admit who dunnit! At the last Sawmill Day festival, I plugged the building into one of my golf cars for power and everything worked. The solar will be permanent and when the museum is open on Saturdays, visitors will be able to see the displays better with the lights on. Why the big push? After a 2 year Sawmill Day hiatus, in deference to the recent plague, the park is in shambles and the coffers are low. We are having a fix up, clean up push to have a Sawmill Day the first Saturday in May. Yikes!
Here’s what happened. I went out midweek with a load of stuff. I always leave something out, but you have to start somewhere, right? First problem was of the 2 pounds of keys I had I still did not have the key to the supply room, so I had no ladder to get onto the roof. No problem. Park the Avalanche at the roof line and clamber up. So I clambered up with 2 solar panels, a power drill, power screwdriver, caulk gun and a bucket of hardware. Well, naturally, there was more than one clambering and I find that with advancing years I am not as fond of clambering as I once was. The ladder would have been better. Nonetheless, let this assure you that age is not a big issue with a small project like this.
The panels were some real oddballs. They are first class GE panels of 65 watts. What’s odd is the open output voltage is 10v and they are an odd shape. I think they were an attempt at solar roof tiles, but not a good effort for that. Still, nice and useful panels. The 10 volt output means that you need two of them to charge a 12v battery. So I used two.
I got a phone call from Roberto, one day. “Hey man, I got some funny solar panels John said you might like”. “Sure, send ’em,” was my normal reply. I thought there were two of them, but each box held two, so I had four. Ok, what to do with them? Bro has been wanting a solar awning for his back bedroom. That would be easy. Then this project came along, So, here I am on a roof with these panels.
The park is full of oak trees so I catch my bearings and shoot for the best location. I accounted for the roof overhang and drilled a hole that I thought would put the wires close to the wall. With low voltage DC, it is best to keep the wires short. After wiring the two panels in series, I poked the wires through the roof and pumped in as much caulk as I could. The panels have a line of screw holes on one edge, so I used them. On the panel above the through-hole, I added a bead of caulk to keep water from running under the panel, insurance for keeping the through-hole dry. Each panel had one line of screws and a good wind might flip them, so I used fender washers and long screws to clamp the lower corners. Not ideal, but it’ll work.
Naturally, one of the things I had forgotten was my meter, so I could not double check which was positive and negative. I took that as an omen to take the rest of the day off. Before I left, I hung an old kerosene lantern from the porch rafter. It has been refitted with an LED car bulb to give a quaint look with energy efficiency and reduced fire hazard. The idea here is to have another light on in the park at night.
On my next visit, Saturday, I was better prepared. I screwed a cheapo charge/lighting controller to the rafter near the protruding wires from the panels. The “LOAD” output was run to the porch’s keroLED lantern. This particular controller is to run the light 6 hours after sundown or until the battery needs to be shutdown. I think this rig is big enough to run the light 24/7, but we’ll start small. Next a Romex line was run from the battery terminal to the battery. 12 or 14 gauge wire is plenty safe for the amount of current here, but a little lossy for a 12v installation. The run is short and the 130 watts from the panels is overkill, so I don’t think there will be a problem. 10 gauge would have been better, but in case I did not mention it, this is a budget installation.
The batteries are a couple of 6v SUN230 golf car type models, recently removed from my Zero Export Grid Tied experiment. 230ah hours when fresh. These are rather elderly and not at all fresh. They’ll do just fine. Russell Brown, another member and a real go-getter had built a shelf for the batteries and had built some some faux meal boxes to hide them. He had even placed the batteries, which was fine with me. I have a not-quite-healed broken wrist that makes hefting 65 pound batteries unpleasant.
Behind and above the batteries I mounted a stub of DIN rail. This is a handy bit of metal to which you can clip gadgets, like fuse holders. I had a couple of 10 amp fuses and that seemed plenty when we are going to run a couple or three one amp bulbs via 20 amp wire. Once connected, the charge controller quickly got the batteries up over 14v and settled into regulation. I now had a 12volt DC power system all ready to go.
DIN, by the way, stands for German Industry Standard. Those Germans spell things differently.
Next issue is to figure the best route to interconnect the building and the battery. After a quick study, it appeared to be easier than I had feared. I was running low on wire and…have you priced copper wire, lately? Did I mention we are a budget outfit?
The light in the blacksmith shop is on a switch, but the one in the mill room is always hot, so all I had to do was go up a few feet to the rafters and over a few feet to the fixture. A piece of 12 gauge Romex was fitted with ring terminals and divided by the fuse holder at the battery end. Staples held it in place and I wired into the main line connected to the light. I spent $6 to change out the light fixture with a pull-chain fixture so the light can be turned off. In the light fixtures I installed new 12w LED bulbs with standard Edison bases, less than $5 each. I am trying to get John to stock these bulbs for some of his customers on a budget. Not every system needs an inverter, you know. Black wires are hot in an AC power system, so black became my convention for +12. Tighten up a few screws and we are in business!
Battery boxes can be seen under the lower edge of the right hopper.
These bulbs are rated at 1050 lumens, so the blacksmith shop is bright, too.
With a couple of “Y” adapters from the hardware store, we are now up to 2100 lumen in each room. Had to do something with the extra bulbs in the 5 pack.
Saturdays we usually have a crew come in and socialize or do some work around the place. We usually have some people drive in from US29 to see the museum, so someone will take a break and give a tour. Most of our crew was at a local festival across the state line in Flomaton, hawking our books and panhandling, so there were only 3 of us at the museum. We had 3 tours come, the last family came in just as two of our folks were leaving. I was finishing up the solar, cleaning up the mess and feeling fine with the results, so I talked with the last group.
The family had bought an old house and wanted to know about it. I answered their questions best I could and offer some resource suggestions. They asked about the park and our operation and I answered those questions. The gentleman thought a minute and offered a donation of $1000.
It was a good Saturday.
–Neal
Notes. John asked questions, so I thought you might be wondering, too….
The items in the blacksmith shop came from a working shop, donated by the Ealy Black family.
One of the gristmills was local. It had operated behind the blacksmith shop in South Flomaton, which is now part of Century. When the mill business closed, the mill was moved and used on a farm outside of town in Skeeter Flats. It was donated to us after a storm flattened the barn where it was kept. Oh, yeah, that was a neat trick to pull over a half ton of machine out of a collapsed barn and onto a trailer. We have actually demonstrated making meal with it, powered by a John Deere 420 tractor. It can turn out 1000 pounds of fine meal per hour with ease.
The large wooden Williams mill came from Knott’s Mill in Butler County, Alabama. Recovering it was another trick as the floor was rotten and the door was not as big as the mill. We recovered the 2200 lb. Fairbanks-Morse engine, too, which was an even bigger challenge. At one point the mill was being moved in our building and it ended up on my hand. One of my knuckles is embedded in the bottom of the wooden skid. I have generally avoided dealing with it ever since.
The lion head fountain was the centerpiece of the formal garden at the residence of Edward A. Hauss, head of the sawmill. When he died he stipulated that his house be torn down for fear no successor would properly keep it up. The property quickly grew over. When the Historical Society got the property, there were all sorts of surprises to be found when we began clearing the overgrowth. Hauss had no worry about pumps for the fountain. The town had two water systems. Indoors you had the drinking water. Outside faucets and fire hydrants were provided with water from the mill pond. Pond water flowed from the lion’s mouth.
The 40 ton Baldwin 2-6-2 locomotive was used as a yard engine by The Alger-Sullivan Lumber Company and to run supplies to the camps. By the 1950s it was parked in front of the mill on Front Street. It was the town baby sitter. New mill owners sold Old 100 for $7500 to a scrap yard in Mobile. They restored it and used it as a yard engine. In 1976 it went on national tour. Later it was sold to and operated by the Whitewater Valley RR, hauling tourists in Indiana. I found it disassembled in their bone yard. We bought it back for a whole bunch more than what the sawmill sold it for. It left Century on one truck and came back on 4. Some assembly was required.
The boxcar, home of our railroad museum, is original to the locomotive and it was used for hauling supplies to logging camps and the commissary store. Somehow it got separated and ended up in Pensacola. We got it donated back to us long before we found Old 100, but we had to pay postage. Ever tried moving a boxcar with rails attached? And getting it over a fence? Easier than you’d think.
If you wanted to put together a similar solar power system for a cabin or shed at your place, how much would it cost? I normally avoid keeping records on my projects, just in case the wife asks. In this instance, most of it was junk box stuff I had on hand. Free panels from John, retired batteries….stuff just accumulated. I only bought a box of bulbs, a light fixture, and a couple of “Y” adapters, so less than $40 out of my pocket. All told, if you bought new, maybe $500. An underground utility wire would be more in our case. And more work.
Recycle, Reuse, Repurpose
Use it up, wear it out, make it do or do without. That was the family motto of a friend’s crew. They were of Scots descent, so you know they were tight. How tight were they? Well, they had a Willy’s Jeep, a ’55 Ford station wagon and a John Deere tractor. Among them, there was one good 6 volt battery. Dad took the Jeep with the good battery to work. Mom would say a prayer for the Ford when she set out for her errands. If it didn’t start, she’d assume God meant her to stay home or visit an ailing neighbor. True! The parents are gone now, but over 60 years later I still keep in touch with my friend. I frequently hear that motto.
He’s working on a solar project right now, with me checking his work by text and email. He invited me to come up to North Carolina this week to be there when he turns the project on. I told him I felt safer here in Florida!
Anyway, I have some Scots blood in me, too. I was at Home Depot a couple of weeks ago with the intent of buying some materials for raised bed gardening. OMG the price of wood! I thought about it for a minute and decided I could repurpose some things or use some of the lumber I had left over from building the barn back in ’87. Carpenter bees have been in it, so I don’t want to use it for structure. Then I had a better idea. I have about 200 bad solar roofing tiles I was going to use as inert roofing material, but they are just right for garden beds, too. Instead of buying lots of big lumber or landscaping timbers that might leach toxic treating chemicals into my veggies, these things are inert and only required 16′ of 2×2 lumber I already had to tie together a 6×6 bed. As time permits I will do some long skinny beds and composting beds, too, to save on potting soil. Deck screws hold the 2×2 to the panels and the corners are done with sheet rock screws.
I normally just plant potatoes. The deer won’t eat those, but they always manage to get anything above ground. This 6×6 bed is being planted as a 3 Sisters garden, like the Indians planted. The corn is already emerging. Soon I will plant the squash, which will spill overboard, and when the corn is tall I will plant the beans to climb the corn stalks. These 3 give a healthy blend of proteins and other dietary goodness.
The stack of timbers in the background is a tater bin. Those timbers are repurposed from the time we had a trailer collapse when overloaded with 100,000 lbs. of fertilizer. Hosting crop dusters means I get free fertilizer, but that incident was a bit much.
That leaves the deer, but it isn’t the end of repurposing. The solar shed and the west bank of ground-mounted panels give good protection on two sides. Some old farm gates from the bone yard have been brought into service. That leaves only a little bit of fencing that will be needed to keep the wily varmints out.
John is doing a little repurposing, too, but with live panels. He and I both have some oddball GE panels that are perfectly good, but in an odd format. He lives in a highrise and can’t go sticking panels to the condo walls or roof, but he is planning to mount them horizontally on the balcony rail. They’ll serve as a table during the social times and provide him with backup power during those post-storm outages we sometimes get here in Florida.
Moral of the story: think outside the box on how you use things in their prime and again in their afterlife.
–Neal
Meanwhile Back at Cory’s Farm
Armed with new info from downloading a couple of newer versions of the inverter manual, I returned to Cory’s farm to try some new settings. I was confidant I had the answers.
Somewhere between the time of the last blog and this trip I had made some setting changes and the reaction was not as I expected. The newly downloaded manuals showed some extra menu levels not indicated in the original manual. With the strange entry method of the Mate3 terminal, it would be easy to hide some extra menus. As Cory was sampling batteries, I jumped into the menus and found that there were no more! It seems there may have been some software updates missed, so no new menus.
Software updates always worry me. Things can go wrong and then you have nothing. As a rule, my philosophy is if it ain’t broke I won’t try to fix it. Here I was, though, trying to fix it because Tom had not set it up for max performance. The mode selection did not seem to cover our circumstance. We were not off grid. We were not selling power back to the grid. We were not using it as a UPS (uninterruptible power supply). I had chosen Backup Mode, because it seemed to be the least unlikely.
Powered up, the inverter made power. After 5 minutes, it switched the load to grid power. Whaaaat? That’s why I thought there was another menu item. In the revised manuals, there is.
As I was fretting over the lack of the menu item I wanted, I noticed a funny thing: it was working. It had been working since my last visit! Here’s what I think happened. I programmed it correctly, but did not understand some parameters. Many AC devices, like inverters, microinverters or even your home HVAC system have a time delay of 5 minutes before connecting to AC. It’s the law. After running on inverter for 5 minutes, the AC kicked on. In the menu there are two items defaulted to 60 minutes. I think this is where I got tangled up. I was messing with the AC input, so it decided to run on AC for an hour. Then it switched over to normal operation, with the inverter supplying the power.
Since the battery is yet a bit wimpy, the inverter was switching over to grid around sundown and firing back up around 7am, according to the logs. The switch at the house has not been thrown and will not be until we get the batteries in better shape. Still, there is quite a load. The workshop, the hangar and an occupied camper are all powered by the solar and the camper seems to be averaging around 3kw. Its two a/c units run constantly during the day and the resistance heating runs at night. This is NOT an efficient residence for the couple who are staying there. The solar power system is operating about 11 hours a day, at present, so even with one so-so battery Cory is on track to save about $100 on the power bill this month!
The operating battery is improving, at around 50% capacity, now., maybe better. The other one has no bad cells, but is badly sulphated, so I installed a defibrillator (actually, a desulphator) and will let that run a month before lashing them back together and applying a good, long desulphating and equalization charge. After a week on the defib, the hydrometer is at least floating a little on the weaker one. It is a 510 ah battery, so a 1 amp defibrillator takes a while to charge it. Once in EQ mode these batteries will need to hold above 62 volts for quite a few hours and drink a lot of distilled water in the process. Yes, it is a lot of work, but to get 2 giant batteries for the price of a set of golf car batteries will be worth it.
If Cory saves just $100/month, the batteries will soon pay back their cost. Throwing the switch to the house is likely to result in even more saving, even with the current limitations.
Next time we’ll talk about Brad’s OMG 27kw solar power system and how he can make it better. AND how he can stop the power company’s latest move to screw him over.
–Neal
You Gotta Write The Book!
John’s on my case, again. “Neal, you’ve gotta write the book on DIY solar power!” He gets this way, sometimes.
It starts with flattery. Continues with pleading. Sometimes he promises, “I’LL PAY YOU, I’LL PAY YOU!” If you know John, the phrase, “I’LL PAY YOU, I’LL PAY YOU!” is usually only uttered when he is running from a knife-wielding cabbie he’s stiffed. Honest! That’s a story best told by John, himself.
I have written books and have 4 in the works, now. I just don’t have the time to concentrate on all the stuff that happens AFTER the writing. One of the books is about my epic 44 day trip aboard the Sun King, solar-powered launch back in 2015. It is cleverly titled, “44 Days in the Sun.” Maybe I could share a chapter or two, since there is some useful info on solar power in it.
My first few books, history books, were written 2 pages at a time, I like to say. I did a weekly newspaper column back in the 90s and early part of this century. I compiled those pages and a few photos into books. So, if John asks, I’m writing his solar book a page or two at a time with this blog, OK?
There is no way you could write a book to cover all cases for solar power, at least not a book small enough to carry or cheap enough to afford. I think it would have to be a series of books in various niches. The basics are pretty simple. It is the details that get you all tangled up.
In a way, though, the book has already been written. I was reminded of this recently when I was called upon to recommission a system I took down a while back.
Some time ago I told you about shutting down Tom’s system. It was not working. Tom was dead. Jane was trying to get the house ready to sell. She didn’t want the unauthorized solar power system to be an issue with inspectors.
Now, Cory has the place and wants the solar power to work. I suggested he budget $20,000 for batteries if he really wanted to do it right. When he regained consciousness, he avoided me for months. Some time later, I came across a battery deal that was too good to pass up. It was him or me and I let him have it. $1000 for 1020ah of second hand forklift batteries from a mobile solar power system. Plus postage and handling. (No, they are not the Edison forever batteries) The seller said they were checked out and good. This remains to be seen, but they are worth the thousand in scrap value if they don’t work out. Cory and a buddy made a made dash to South Florida to fetch them and that was the last I heard for months. It isn’t good to let batteries sit for months without attention.
By the way, it happens that 1000ah is a good starting place for a home system, though a little small for the 10kw solar input of this system. Tom had started with 400ah and added 200 ah, later, repeatedly cooking them. New, the big batteries would be about 5 grand each. 4 of them would be nice….and 20 grand.
Then came the call. I made suggestions as to placement of the batteries and carefully avoided being there when the move occurred. They weigh 2000 lbs. EACH. He ended up with a sheet of foam on the floor, a sheet of black poly plastic and painted 2×4 rests on top of that. You don’t want batteries on a bare concrete floor for two reasons. A cold floor will cause stratification of the electrolyte and spilled acid–it happens–will dissolve the floor.
Connection was pretty easy. I converted the cable that came with the batteries by chopping off the Anderson forklift plug and installing some substantial ring terminals. I had the crimper with me and used Cory’s torch to solder the lugs for insurance and then shrink down the red and black shrink tubing to make it neat and pretty. When I took down the old system, I hung paper tags identifying stuff, like the battery cables. I removed the hodgepodge of cables and a bunch of shunts that Tom had installed to monitor pretty much everything that could happen. TMI, I say. Too Much Information and too much crap to confuse things. That stuff got ripped out. New cables installed, it was time to smoke test it.
I waited until Cory got back from the Piggly Wiggly with 10 gallons of distilled water. The battery seller had claimed he topped them up, but we added 7.5 gallons if that tells you anything about the seller. OK, maybe there was some evaporation. It happens. When Cory returned, I had him start pouring.
Let’s have a little educational chat, here. Always use distilled water because it does not contain minerals that might interfere with the life and operation of the battery. The stuff costs a buck a gallon at the grocery or Walmart. It is absolutely imperative to keep the water/acid electrolyte above the plates, otherwise bad things happen. It is also imperative to not overfill the battery, as that can go badly, too. There is a split plastic ring down the hole. Better said, the fill tube extends into the cell, but is notched. Your target is to have the acid mix (you are pouring in water, but there is acid in there, which is not good for you) come up to the bottom of the split ring. That is for an active battery. These were cold dead batteries. Cory started out on the low side of filling and got better as he went along, or at least the cells got more full.
All watered up, it was time to throw the switch and see what happens. Main battery switch on, inverter pair and charge controllers light up. Combiner boxes switched on, solar inputs switched on and the current starts to flow. Lots of it. The panels are filthy and set at the wrong angle, but there are lots of them and the system came to life.
One of the batteries started bubbling vigorously. It was taking a charge. The other, not so much. The voltage came up quickly, so I got into the FlexMax 80 charge controllers and set up a 6 hour equalization. I am familiar with the FlexMax and even remembered the password (shhh 141) so I did not have to get into the documentation pack that had been left atop the inverters. The bubbly battery quickly warmed up just a little and all that electrolyte was expanding. Some was overflowing. We loosened the caps to all the cells to give them a little more breathing room. It wasn’t enough for some of them. See why we isolated the floor from potential acid spills?
I gave Cory another chore. Obtain a new hydrometer and a notebook, then sample all of the cells. Next morning when I arrived he had his notebook and was just about to begin the sampling. The one battery was bubbling away and the other was giving only the occasional bubble. The hydrometer was not working so well. Cory had overlooked the fact that the maker had stuffed a strip of foam inside to keep things from rattling about and breaking during shipping. It worked better then. I commented that these tools are made of glass and are fragile, just before something fell and broke it. We sampled with another. One battery was in the high red zone. The other would not even float the bulb. This is going to take some effort. At least the cells were consistent within each battery.
Now, while Cory was taking and recording samples, I was trying to fine tune the inverters as I remembered something Tom had said about his setup and thought that we could get a little more out of it. In this case, I was in new territory with the Outback Radian GS8048 inverter and the Mate 3 monitoring interface. I needed to read the book.
Boy what a book, since we are talking about books! There is a lovely poster that graphically shows all the connections you need to put together a system using Outback products and it really was all you would need to put your own system together. Programmable stuff always freaks me out a little, because it requires thinking and care. There are even different trains of menus, setting up the system in different ways.
One thing stumped me, possibly because I didn’t have all the documentation, even though I think I did. I did not see a good discussion of the 3 operating modes and why you’d want to use one or the other. I chose BACKUP mode. The other thing I did not see was how to get into those lovely menus and how to change things. So I just started pushing buttons until I found the entry menu. First thing it asks for was the password. What? There was nothing in the notes about a password. 141 might have worked. 1723, I think, did work. Whatever it was, I wrote it prominently on the manual.
The really baffling thing was how to enter the passwords and other choices into the system. Thank you, “OK Google.” If you look at the Mate, there are not a lot of buttons or a keypad. That “target” area in the center is like a racetrack. Run your finger around it clockwise or the other way to make the numbers go up and down. The bullseye is the ENTER button. Simple, once you know.
Everything is running, but we have yet to throw the switch at the house. We are giving it as many days as it takes to bring the batteries up to full power (we hope). All went reasonably well and a big help in setting up a strange system was having The Book. The book that came with the hardware. The manual. The hardware always comes with a book. Some books are better than others, but usually they are very useful. Read The Book and learn.
I’ll have more about the system rebirth, soon. It is a work in progress.
–Neal
Don’t Have An Ugly Roof
Solar panels on a roof can blend in and be hardly noticeable or they can stand out just enough to be bragging. On the other hand, some folks manage to make it really ugly. Don’t have an ugly roof.
I am on the mailing list of a lot of solar newsletters. They include a lot of pictures of roofs. Some are pretty ordinary and some are strikingly clever…artistic, even. Then there are the ones that rate a few internet terms like OMG! and WTF?!
One that comes to mind was a lovey bucolic setting featuring a barn equipped with solar panels. Instead of going with the flow of the barn’s roof line, complex mounting structures were added to make the panels align just so, according to some optimum specification! It was hideous! OMG, WTF were they thinking? Match up with the roof. It creates less wind loading stress and it looks so much better. If a slightly less than optimum alignment doesn’t give enough power, then just add more panels. They’re cheap! Probably the panels were cheaper than those ridiculous mounting frames.
Another one you see a lot is where the roof of a nice house looks like a hodgepodge, with missing areas. These are because the solar guys left out a panel where a plumbing vent pierced the roof. It does not have to be that way. When I built my house I wanted minimum roof piercings, so I tied all of the vents together in the attic for a single pipe on the backside of the roof. When I recently (finally, after waiting over a year) got a new roof on my house, I got rid of that one piercing by installing a vent valve in the attic. This is like a check valve that lets air in to allow the sinks and toilets drain properly, but does not let sewer stink into the attic.
Installing these in your attic and capping or patching the roof hole means that a uniform grid of panels can be mounted without jarring visual disturbances. Guess what else? You get to fill in those ugly gaps with a few more panels.
–Neal
Form 5695
I finally started gathering forms and am evaluating who has and has not sent me all the stuff so that I can do my taxes. Seems like something is always late and now I hear that if you have a farm you need to file by March 1st. Yikes!
Since this is a solar blog, I thought it best to remind you to download Form 5695 and Instructions if you bought any solar gear this year! That’s the one for energy upgrades, including solar, that can result in you getting a tax credit.
I have filled these out several times and ended up not getting the credit. That is not necessarily a bad thing. Being retired and lazy I can usually structure my income to a level that does not involve paying taxes. If you don’t owe taxes, you can’t get a credit on them. Sorry. On the other hand, if you don’t owe taxes, is that a bad thing?
If, unlike me, you just installed some solar power and are gainfully employed, take the deal!
—Neal
Other Batteries
A reader wants to know if I have any knowledge of Nickel-Iron or NiFe batteries. See? I read the comments. Eventually. I just don’t let them post because not everybody is nice or on topic. Anyway, let’s just say I’d love to have a trailer load of NiFe batteries, aka Edison batteries.
Thomas Edison wanted to build electric cars. Seems like every body does, today, but about a century ago things were kind of up in the air as to how it would all go. Steam, gasoline and electric started on an even footing. Range and complexity were big factors and gas eventually won. Edison, though, was looking for a battery that could take a lot of abuse, was lightweight, would last a long time and not rot out the car frame. Any golf car owner can tell you about frame rust from lead-acid batteries.
While electric cars had to wait a century before coming practical, Edison’s were a hit in stationary applications, like railroad signals, wind-electric home power and in forklift trucks. When Exide was bought out, NiFe or Edison batteries were discontinued because they almost never failed. If you have a battery company, do you want to make the best product or do you want to sell lots of product? They made their choice.
The story is told of an old man who went around buying up his neighbors’ batteries when the Rural Electrification Administration brought lines out in the countryside. It didn’t matter if they were old and dried out, he’d wash them out and refill with water and a little lye. No acid, no corrosion and they come back to life. There are still people using these batteries, many over 50 years old.
For the longest time, the only sources for new batteries were eastern Europe and China. There is now an American manufacturer.
What are some of the characteristics, good and bad? On the negative side, they use a lot of water. The railroads topped them with “Edison Oil” to slow down evaporation. They don’t retain a charge for long periods, but they are fine for a few days of cloudy weather. Can’t think of anything else.
On the positive side, they seemingly last forever. You restore them with water and a can of Red Devil Lye. They won’t corrode things, but you don’t want to get the lye on your hands when servicing. They aren’t heavy, as batteries go. They don’t seem to have a cycle limitation. You can run them down to stone cold dead or bone dry and they come back just fine. There is no desulphation or equalizing charge needed.
Sounds pretty good, right? To use them, you’ll need charge controllers that can be adjusted, and many are, but otherwise not much difference. From what I have seen, they are sold as cells rather than, say, a 24v battery. This would be perfect if they were cheap. Well, maybe they are. Last time I priced some, they were about the price of Lithiums. Lithium batteries have a high upfront cost, but they last a long time and have deeper cycles making them a better deal than lead acid batteries. The NiFe batteries appear to take it a step further, making them a long term bargain. The bad news is that Sun Electronics does not carry them.
–Neal
Header photo credit: Iron Edison
The Dirt on Solar Electronics
If you are looking for a scandal, sorry. I’m talking about actual dirt.
Just about any serious piece of electronic gear comes with a manual, which I am certain you read cover to cover 3 times before attempting to install…right? Somewhere in there you will usually find the admonition to “mount in a cool, dry place with temperature range X to Y, and humidity below 95%, non-condensing.” Or something like that. If you just paid 5 grand for a fancy inverter, you probably go along with that.
The 95% humidity thing is always worth a giggle here in La Florida. Sometimes the humidity is actually below 95%, but not for long. Sometimes it is more like 120%. Seriously! Many nights we’ll get a convection fog that just rolls right through the shop end of my Solar Shed, getting my motorcycles and tools sopping wet. That’s where you bust that “non-condensing” bit in the manual.
If there is any dust or dirt on the circuit board and you add some damp while power is applied, the electrons can start making unintended paths and and doing unintended things. This is especially the case where you are making 120 or 240v in the same box where the control circuits are 5 volts. I avoid this with Sun King, my solar-powered launch, by just leaving it on all the time. The little bit of heat from the circuits keeps the moisture out.
My solar power system for the house is actually two in parallel. In the winter I run the inverter in the control room to help keep the Man Cave warm. In the summer, I run the other inverter, which is mounted in a cabinet outdoors. This keeps the Cave cooler with less a/c. Ideally, the summer inverter should be in the a/c, but it is actually designed for high temps. It is not designed for high moisture of winter, so I leave it powered up on standby to keep the humidity out. There is also a Midnite Solar 250 in there that can get pretty warm when the sun comes out.
This gear is treated pretty well and within specs. A little wipe with a clean 2″ paint brush every now and then is sufficient to keep the screens clean to allow good airflow for cooling.
Then there are the buggy inverters. My electric farm vehicles are pretty much never clean and dry. They get used for pretty much every purpose on the farm from hauling firewood, towing trailers or joyriding. The inverter runs the electric chainsaw I use for firewood. I have given up on gas saws. Fortunately, there are some serious electric saws, like my Oregon. The battery saws are ok for light work, but not for prime time. I cut down a couple of trees and buck them to the size the furnace likes, then haul them back to the woodpile. Lots of dirt and bark is involved and there is usually a thick layer of it on the cargo bed and some invariably settles down on top of the inverter.
Should I be surprised that the inverter in the Yamaha started acting funny and quit. No.
Here is step one of my cure for dirty electronics. I put the inverter on the clean workbench so I would not lose parts. Then I removed the cover and went after it with a paintbrush and air hose. Yup, it was cruddy in there, but once it was all cleaned up and put back together again it worked for another few loads of wood. But it was too soon to celebrate. We had more dirt and one of those really soggy fogs roll through. This time, the brush and blow did not do the trick, so time for Plan B. I had the notion that humidity had gotten into the transformers or inductors where it should not be, so I determined to drive it out. The dashboard of your car on a hot day with the windows up can make a fair oven, but so does an actual oven. The wife and my ex-daughter’s sister (long story) were baking a treat one afternoon after school, so when it was done I let the oven cool a little and popped the inverter in until it was completely cooled down.
Sounds crazy, but it worked and I avoided freezing to death with my firewood supply resumed. Freezing? Florida? Yeah, it happens a lot in Northwest Florida. If you try the oven trick, just preheat to a temp that won’t melt plastic and turn the oven off. It is a desperate measure, but with sound underlying principle. Besides, the thing wasn’t working, anyway, so what’s it going to hurt?
–Neal
Boxcar Solar Revisited
We were having problems with the lights in the “boxcar”, so I decided to rethink it’s solar-powered lighting.
It isn’t really a boxcar. It is a 40′ shipping container that looks like a boxcar without the wheels. Very handy. Initially I did a full blown install and it worked well. 4 panels, charge controller, battery, inverter and LED strip lighting. Then it got to where it didn’t work too well. It would cut off after a while.
The old lighting system required that you bend down, open a cabinet and turn on the inverter. All the lights came on. All or none. Fine, when it works. I diagnosed the problem as a dead cell in the battery. The huge, grossly expensive battery. The battery went to the Solar Shed for reconditioning, where it has thus far resisted my efforts. I have pulled out all the stops, calling upon the black arts of battery reconditioning. You might not do that for a 9 year old car battery, but this battery costs $1200! See why I’m trying to save it?
Back to the system, I thought maybe I could improve it and make it easier to use. And you can use a similar setup for an out of the way home, hunting camp or storage shed.
I kept the 4 original panels. They are kinda weird, but perfect for this application. And they cost $7 apiece. Sun hasn’t advertised these in a while, so they may be out. These are FS-70 amorphous panels. The important thing to know about amorphous or thin-film panels is that they work better in the shade than crystalline panels. They are sitting flat on top of the boxcar, connected in parallel. The boxcar is in a dense forest and the roof only gets a short period of direct sunlight. 280 watts is a lot for a little light, but the odds of getting 280watts in the shade, with leaves raining down is slim. It is a good match.
I have a DIN rail with a fuse holder/disconnect and that goes into an MPPT charge controller. This particular controller is one of many I auditioned for the Solar Yacht project. It had a bright, clear display and no fans to suck salt air into the electronics. Sadly, the designer missed a spec on the display’s info sheet and soon the display went to gibberish. Everything works great, but I can’t read the meters or change the settings. I had 3 of them in the junk box and recruited one for this project, since I would not have to spend any more money.
The reason for using the MPPT charge controller is that these are 90v panels. You need to use a Maximum Power Point Tracking controller to step the 90volts down to 12 volts. If you have some 12 volt panels, which usually max at 18-20 volts, you can use a cheaper, simpler Pulse Width Modulation (PWM) controller or a simple on/off controller to handle battery charging. Roberto can fix you up with a simple unit by EPever at a good price. I used other EPever controllers on the Sun King launch and they are still running years later.
The output of the charge controller goes through a breaker on the DIN rail and on to the battery. You’ll need to calculate your fuse and or breaker size. My panels have the rated current on the back, less than an amp, and there are 4 in parallel, so the max current will be under 4 amps. Probably 5 amps will be the closest size to that. On the output, 280watts/12v=23.3 amps, so round it off to 25 amps. REMEMBER, these are numbers based on my gear and you will need to calculate your own. You DON’T need DIN mount circuit protection. Your auto parts store or ebay has small fuse blocks that use automotive fuses. They cost only a few bucks and you can get fuses anywhere.
Now to the battery. You don’t need a huge $1200 battery. To tide things over while chanting and dancing around the big battery, I took a 14ah battery I rejuvenated from my motorcycle and it works great. I had decided to just buy a new one for the bike, so there it was. It is in there on a temporary basis. A car battery would be fine, too. Obviously, a new deep cycle battery will last longer, but sometimes it’s ok to “run what ya brung.” We’ll get back to this philosophy in a moment.
The boxcar is full of shelves, from stem to stern. 8′ sections to the ceiling on one side, making handy high points for mounting the lights. The lights are 12v LED bulbs in the standard Edison format. They will actually run from 8 to 24 volts and only use about an amp! Remember that. We’ll have a test, later.
I put standard metal boxes on 5 of the shelf uprights and strung 12gauge copper wire from the battery to the last bulb. The fixtures I put on the boxes are standard pull-cord fixtures. You can walk down the narrow aisle and turn on the lights as you go. Each is equivalent to a 75 watt incandescent.
I got the bulbs on ebay in a 5 pack. Boxes and sockets came from the hardware store. Thank goodness I had a roll of copper wire! That stuff is getting pricey. I think the bulbs are non-polarized, but I put the positive wires on the brass-colored terminals of the sockets and negative to the chrome.
OK, here’s the test I promised. What is the voltage range of the bulbs and how can that make the project even less expensive? Answer: 8 to 24volts. My inverter was getting a low voltage shutdown from the bad battery because the inverter won’t run at 10volts. These bulbs will. That means you can use a battery with a dead cell that you might have in the garage because it won’t start your car. I always have bad batteries around for trade-ins or recycling. If the big battery cannot be reclaimed, it will still work fine in the boxcar. It would run the lights 24/7.
So there you have it. No worry about a tiptop battery. No extra step of starting and stopping the inverter. Lots of light.
–Neal
John’s Back on the Air
He’s blogging again. Watch out!
John Kimball, founder and bossman at Sun Electronics, stepped away from blogging for quite a while, but he’s back. I generally try to stick to something along the idea of how to make solar power work for you. John often talks about things going on in the industry, but sometimes he might show you pictures of a colorful Arizona desert landscape or stunning fish off the jetty in Miami. Sometimes he just goes bonkers. There’s a link to John’s blog on the menu bar of most pages at sunelec.com or you can go direct to www.johnssolarblog.com. It takes a while to load with some internet service, so be patient. Check him out.
Greener?
If solar power is green, can we make it greener?
Yeah, and a lot of folks are going that way. More directly to the point, is what do you do after you get a ground mount panel rack installed? Put down gravel? Mulch? Grass?
NextEra or FPL is grinding up all the pallets on which the 200,000 panels came to our neighborhood solar farm to make mulch. Ok, but, given what those pallets cost, couldn’t they send them back to the factory and get the next load of solar modules shipped on the same pallets? I think that would be a better idea, but they didn’t ask me.
Now, for actual greenness, let stuff grow under the panels. I have not planted anything in particular under mine. Green just happened, with grass and weeds starting in immediately. That’s not bad, because panels operate more efficiently when they are cooler and anything growing under there will increase cooling because of evaporation from the leaves.
Agrovoltaics is what they call combining agriculture and solar farming. One popular option is wildflowers. This keeps the panels cooler and helps with our dwindling bee population. No bees, no food, so that’s good to keep the bees happy. Some farmers mount the panels a little higher and let sheep graze underneath. That takes care of eliminating the need to mow.
I wondered about planting food under mine, but they are fairly low and I am concerned about what fertilizer might do to the steel posts. Clover or some flowering ground cover, like purslane, would be good options and I am sure my wife would approve.
Anyway, cooler is more efficient and green is cool.
–Neal
Battery Rejuvenation
Anyone who has batteries in their backup or solar power systems will eventually have a battery go bad. Can it be brought back to life?
Maybe. Of course you want to take good care of your batteries in the first place to put the dreaded day farther down the road.
Let’s start with lithium, briefly. The Lithium Ion or Li battery packs are usually made of scads of little cylindrical cells welded together. Lithium Iron Phosphate or LFP batteries tend to be larger “prismatic” blocks bolted together. Many Prius owners have gotten the dreaded “Get a new battery pack” light and sold their cars cheap when the problem was only a loose or corroded interconnection. On your home solar batteries, if possible, periodically check all the battery connections. A loose or corroded connection can provide reduce or no output. This goes for any kind of battery. I have shown you pictures of batteries damaged by hot, loose terminals.
The biggest frustration you may run into with lithium batteries is an over-discharge. Lithium batteries can be severely damaged by running to extreme discharge. To prevent this, and overcharge, they have a Battery Management System or BMS. These can be external or internal. Let’s say you let the battery get low and then left it alone. While neglected it self-discharges further. Now you have a battery that will not charge or discharge! Oops. Pay attention, now, because even though you may not have lithium batteries in your home power system, you have them. Power tools, phone batteries or that drone that got stuck in a tree for a month…all lithium. I have bought old stock tool and phone batteries on ebay that would not charge. The trick is to open up the case and jump off the battery to get the voltage above the BMS threshold to operate. Use a battery of similar voltage. It usually only takes a few seconds. I have done this many times. If an individual cell goes bad in the battery you may need to replace it or have a pro shop handle it.
Now on to lead acid batteries. Oh goodness, get on the internet and you will find people offering to sell their books of secrets for reviving dead batteries. Many of these tactics will work to a point, some provide only short term relief or even cause more damage.
I added up what the approximate retail value of my batteries would be if I replaced them all and was stunned to find it is around $80,000. I did not buy new or retail, so it wasn’t anywhere near that. Nonetheless, there are literally tons of batteries and some go bad, both in the solar system and in all my vehicles and farm equipment. It makes me sad to buy new batteries.
The internet guys will try to tell you that you can put some aspirin or epsom salts or EDTA in your battery and all will be well. Chemicals may provide a short term boost, but understand that the end is near. Some of them will have you dump out all the acid, rinse with distilled water, charge with distilled water, rinse again and refill with acid. Why? Stuff flakes off the plates and falls to the bottom of the battery, especially when you let the electrolyte get below the level of the plates. Maybe the bottom fills up. Maybe the stuff lodges between the plates. Cells short out and the battery dies. (Or it blows up! A friend with a pair of 2000 lb. batteries had a cell blow, probably from not keeping the water up.) Ok, in theory, thoroughly cleaning out a battery may help, but is this safe or practical? Two of my batteries weigh nearly 2000 lbs. EACH. Let’s see you dump those! A pro shop can remove the individual cells from that type of battery, so it can be done. (My friend is having the blown-up cell replaced.) A golf car battery weighs 62 lbs. and a person can handle that, but do you want to be struggling with a heavy battery while trying not to get acid on you? Then what do you do with all of the old lead-tainted acid?
Since it has gotten cool, I have had several batteries go bad. I’ve brought two back to service, have 2 more in process, showing promise. I’ve only bought one battery for a really bad one in one of the tractors. My method is to check the electrolyte and put the battery on a slow charge. A simple charger may work best. Some smart chargers, which are common these days, are too smart for their own good and may or may not even start if the battery is severely discharged. In that case, use jumpers from a good battery to convince the charger to start. Use the 2 Amp setting and no more. This will take time. 2 amps into a 200 amp/hour battery is over 4 days, for a GOOD battery. A bad one will take a while. Check the voltage from time to time. Make sure the battery isn’t getting hot. Using a higher charge rate or letting a smart charger do its thing nearly always ruins the battery. A 12v battery needs to spend some time above 15 volts to break through all the sulphation and get it back into the electrolyte. If you get it that high, put a load on it to see if it has some guts. If the voltage drops quickly under load, put on a modest sustainable load and run the battery down and start over. It may take several cycles.
My quickest refurb was a 14 ah motorcycle battery, which took less than a week. (a week is maddeningly long when you want to ride the “new” bike.) It had not been run in a couple of years and now has no trouble starting the bike. Another battery, an Outback RE, was killed twice by a solar owner and then died in my tractor. It came back and is working fine. I have another Outback I am trying to revive for the 3rd time. My biggest challenge of the moment is a $1200 agm battery that powers my boxcar solar lighting system. It had a cell go bad. I have gotten it to accept charge, but it is not to the point where it really has any guts. I am on day 3 of discharging it with a light bulb. I have high hopes.
The key ingredient is patience. If you crank the charging rate up, you are asking for trouble. If your smart charger has a rejuvenate button, don’t use it until you first go through a regular slow rate equalizing charge. Good luck.–Neal
NOLA Solar Update
A while back, I wondered if all the PV gear installed after Hurricane Katrina was grid tie, or if some of it came through after the more recent storms. The answer is there was some with battery backup.
I remember reading in my morning solar newsletters a while back about an apartment complex that was equipped with solar and battery. That one was working after the storm. Sort of.
Two very important things about life off grid are that you either need a lot of battery for life as usual or you need to be able to make some lifestyle compromises. There are two people in my household and one of us (ahem) is not willing to compromise or economize on power use, so the other has to keep tabs on battery maintenance and be on the lookout to scrounge more batteries.
So imagine what it is like in an apartment complex full of people.
Reportedly, the lights were on during the day, but went out after sundown. Doesn’t seem quite right, does it? Still the refrigerators got to build up some cool during the day. I suspect the a/c units were running, too, leading to the battery shutting down early.
There are some grid-tie inverters for individual homes that have a day-only backup mode that will give you power without batteries when the grid is down. We put one, a Sunny Boy, in a friend’s South Carolina home. I think it was good for 2500 watts on a clear day. That’ll run the fridge, the microwave and some lights, so worth having. I hear, too, that the latest Enphase microinverters (grid tie inverters that strap to the back of each solar panel) can provide off grid power during the day with an additional controller.
Batteries aren’t cheap, but they sure are nice to have. There are other options if you are not able to go with batteries.
–Neal
Racked Up
The 10 panel rack mount is done. 2500 watts of panels are secure and producing power. There are plenty of ways to do this, but this was my way.
A few posts back, I did a blog called Rack ’em Up. That was the beginning of the solar rack project. To recap, I used string as a guide to keep everything in one direction, surplus oil drill stem as the mount with conduit clamps to hold the panels. Now, the rest of the story.
The steel posts were cemented into the ground and the cross bars were welded to the tops of the posts. The panels had some holes already in place, so I used them as a starting point for the clamps. The clamps were attached with nut, bolt and washers and things were more or less secure enough to easily complete the work. The first holes being uniformly punched at the factory made it a snap to keep things neat. The second holes were drilled through the clamp, with a block of wood between the aluminum frame and the panel area to avoid accidentally drilling through the glass. Wouldn’t want to do that, would we?
With the second set of nuts and bolts through the new holes, things were tight enough that the panel would stay where you put it, but you would not count on it in a strong wind. Hence, I began work on a front row mount. I did not have more of the super duty oil well steel, but I had some thinner galvanized conduit and I acquired some 4×4 treated posts, galvanized strap, more conduit clamps and fasteners. The panels were tipped up out of the way and the new posts were carefully planted on a string line.
I gave the posts a couple of days for the concrete to set up firmly, then used the string line again to mark for trimming. After being cut for the angle I had chosen, the steel tubes were placed on the posts with bolts and iron straps. I’m not saying these mounts can’t be wrecked, but if we get enough wind to do it, we’ll have other problems. This time, I used self drilling roof screws to hold the conduit clamps to the panels.
Panel wiring was neatly daisy chained from the ends to the middle. Five panels on this end and five on the other, with 2 downlines to the combiner and Midnite 250 charge controller. There was a lot of excess cable sticking out of the conduit as I had set things loose to operate before the final configuration was decided. To neaten things up and provide a quick shutdown in case of emergency, I put in two disconnect boxes. Wire lengths were minimized and terminated in the disconnects. These were the ordinary type used for outside a/c units. They are dirt cheap and are compatible with high voltage DC power.
The conduit was buried and grass is beginning to heal the scars. I’ll talk about performance checks in another of our chats and show how weeds and grass under the panels can actually help performance!
–Neal