I recently had to burrow into the entrails of my new 21 year old truck’s transmission. It is sort of a right of passage with the old Dodges. Specifications for putting the various pieces back together are very specific. I remember what my little brother did to his Plymouth’s transmission 45 years ago and I didn’t want it to happen on my Dodge, so I bought a new torque wrench. I had one I bought 50 years ago, but it was built for many foot pounds and not the inch pounds required of delicate transmission in the 6000 lb. pickup. The new 1/4″ drive wrench set me back around $20 at America’s favorite Chinese tool store. I didn’t have a coupon.
Having successfully reassembled the transmission, I set out for another load of batteries to evaluate for the Solar Yacht project. Another few hundred amp hours never hurt any battery bank.
These are my biggest batteries yet, but they have the smallest bolts, yet. It uses M6 bolts…less than 1/4″. Most of my others use 5/16. Batteries with just a hole in a post are not terribly worrisome. If you overtighten and break the bolt you just put in another. If you overtighten a top stud battery, like GC batteries, you can pull the stud out, which starts to be a problem. My recent additions have bolts that go into brass inserts in the case. If you break off a bolt you have a real problem. If they are large enough, you might be able to use an extractor. My view of the extractor is that it is a noble thought, but generally not very useful.
The key to not worrying about this stuff at all is to use a torque wrench set to the battery manufacturer’s spec. Do so and the terminal will be tight enough and you won’t break it. I think I set mine to around 80 inch/lbs. for the M6 bolts. Just set the dial and pull on the handle until you feel it click. No worries about too tight or too loose.
I don’t plan to go back into the transmission, anytime soon, so the torque wrench and appropriate sockets will live in the battery room with a few other tools that are commonly needed.–Neal
Every now and then you need to tidy up a bit. I’m bad about that sort of thing. I needed to take a truckload of batteries up to the recycler in Atlanta, but the Chevy just won’t carry enough. Then I inherited, sort of, a Ram 2500, which can carry an additional ton without any problems.
I loaded up and got on the computer to plot a course to the recycler. The GPS course used the interstate, which is scary to a fellow who has to drive 4 miles to find a stop sign. Most of the interstate, say between Mobile and Newnan is not scary to me. But when you get to the outskirts of Atlanta, it just goes crazy. They don’t have cloverleafs show up on the GPS map, they have spaghetti bowls on display. I don’t know if their highway designers are geniuses or just plain nuts.
Using satellite images of the area, I came across the strangest thing. It was a huge building, though from overhead it looked like an alien vessel, just arrived on our planet. Better yet, it was festooned with solar panels.
Hey, if you are going to do solar, why not be awesome about it? I was eventually able to determine that this is the National Archive at Atlanta building. I spoke with a guy who lived nearby and he was familiar with the building, but he’d never seen an overhead view and nothing on the ground gives a clue.
It makes me mad to see that people die after the storm. You buy a generator to keep the lights and fridge on, but the thing can kill you. Here are some thoughts.
First of all, have a battery backup system in place. This can be a building block for a future solar power system or it can be a quick solution. More on that later.
When you buy a generator, also buy a length of stout chain and a padlock. People steal generators and that is why their owners put them in the garage. Running a generator in a garage that is attached to the house can lead to carbon monoxide getting into the house and killing you. Don’t do it. Chain the thing to a tree or car and let it run outside.
Have lots of fresh gas and oil before the storm. You won’t be able to buy it for days because the pumps won’t run and neither will the credit card machines. Store the gas in a safe place in sealed plastic containers. Any thing not sealed and the gas will go bad quickly and it can ruin your generator. Bad gas in my 22 hp lawn mower just caused a stuck valve, which pretzeled a push rod. (See image above) You can’t buy engine parts after your town has blown away. Treat the gas with Stabil, Sea Foam or Marvel Mystery Oil.
Note, too, that most small generators need the oil changed frequently. 25 hours if it does not have a filter and 50 hours with. Don’t buy a used generator after a storm…they probably didn’t change the oil. After you are finished with the generator, let it run out of gas. That nasty stuff they sell today destroys carburetors. Change to fresh oil so you are ready for next time.
A whole home natural gas generator is a thing of joy, but expect a whopping gas bill. Mom spent a bunch on hers and never regretted it. Her neighborhood got trashed by a tornado a few years back and she was the only one with lights and a/c for days.
Don’t refuel when the engine is hot. They can catch fire and blow you up. And burn down your house if you are doing this in the garage. You’d think it a simple thing to put the spout in the hole and not spill anything, but a full can is a bit unwieldy at 30 lbs. and those !@#$% worthless government-mandated spouts make it worse. I broke two of them before I mastered getting the gas out. You can buy bootleg good spouts, but they cost more than the whole gas can used to cost!
Here’s where your battery backup system can shine. At night, it is quiet and not making fumes. You run the generator intermittently at an efficient load to charge the batteries instead of 24/7 buzzing to run light loads. You will use less fuel.
Your car can be the generator. Yeah, your car. After one storm, I was loathe to drag my monster diesel generator out of the barn. When I say drag, I mean drag. It weighs thousands of pounds and is on skids. Getting it out with a tractor is easy, but putting it back is a pain. For 3 days, until I knew the power was seriously out and would remain so, I traded generating duties between an F250 and a Chrysler LHS. There was a 2kw inverter connected to the battery. I would run them intermittently to keep the fridge cold and a few hours in the evening for lights and TV.
That same storm, my bro had a Rubbermaid tote box full of golf car batteries and an inverter on the balcony of his town house. His Chevy and a length of SEU service entrance cable topped them up.
I hauled a load of scrounged batteries and an inverter to Mom’s place and connected them to her minivan.
My later Chevy pickup was fitted with a forklift plug on the front so numerous accessories can be used, including a 2kw inverter. The Dodge Cummins pickup I recently acquired has two huge batteries, huge cables and a huge fuel tank. I have plans for it.
With just the addition of the inverter, your vehicle can be your power plant. Better yet, call Roberto at Sun and he can set you up with a simple standalone battery kit or a fully automatic setup that will switch power to the whole house. Lots of his customers live in places with unstable power, so he has kits for various situations and budgets. The bigger systems won’t be 12 volts, chargeable by your car, but they will be the first step in a solar power system.
Oh heck, why not go solar? Or maybe you have. In the event that the storm might blow away your solar panels, you might consider putting a few under the bed, just for insurance. We still have some time left in this storm season. Get prepared.
This was in the morning newsletter from the American Solar Energy Society.
“A household rooftop solar panel system can reduce pollution by 100 tons of carbon dioxide (CO2) in its lifetime—and this includes the energy it took to manufacture the solar panels. Solar panels can improve future air quality for humans as well as the millions of birds, fish, and mammals that are negatively affected by pollution each year.”
Save the planet! Screw the power company! Go Solar!
Have you connected a battery, a charge controller or an inverter and had rapidly charging capacitors make a loud pop and maybe even a welding arc that messes up a bolt?
That can be really annoying and it can be dangerous, too. I have never had it blow up a battery but I have had it mess up threads on a battery terminal. The large capacitor bank in my inverter always makes an unnerving POP! Recently, after the inverter suffered a dead short, replacing the fuse made a KABOOM! that could have damaged a finger if it had been in the wrong place. It didn’t do my nerves any good.
As I undertook to test and repair the inverter I was a little gun shy. I didn’t want to blow up a new set of transistors in case they were not the only issues and I did not want to cause further damage to the circuit board. What to do?
Sometimes you just have to stare at a problem and maybe talk it over with your accomplices and acquaintances. One such collaborator is Bruce (in Pa.) (We call him that because he is Bruce and he is in Pennsylvania.) The answer seems to be a precharge resistor and you probably already have one.
I should have thought of this earlier because my golf cars, which control some serious amounts of power–600 amps at 48 V– use them. The precharge resistor can not only take the pop out of connecting capacitive loads, it can warn of impending doom if, say, your inverter has a dead short.
Here’s what I did. I found a light socket and a 40 watt incandescent light bulb, a couple of pieces of wire and some gator clips. If you have an old desk lamp, you can use that, just make sure the bulb is the old-timey one and not a CF or LED. I would go with a bulb in the 20-40 watt range. If I need to start up the inverter after being offline (I just re-installed the repaired 10kw module) I clip the light across the empty fuse holder. The bulb glows briefly as the capacitors charge. Then I can slip in the fuse, snug it down and remove the lamp.
No snap, crackle or pop. If the power module repair had not gone well, the bulb would have continued to glow instead of going dark. We would have eliminated the KABOOM!
That’s a big help from something you might already have in your junk closet.
A widow has asked me to dismantle her 4 year old 10kw PV system. It isn’t that she didn’t like solar power, but she has to sell the house now and mortgage inspectors are brutally thorough and her husband had overlooked the business of permits when he installed the system. In the process of going through Tom’s system I am finding some things of interest. Here are the good, the bad and the ugly.
First of all, his original installation featured 200 amps of solar power and 180 amps of charge controllers. You should know that a 200 amp solar system will rarely crank out that much, but sometimes it does. You should also know what you have in terms of gear. The first MPPT charge controllers were 60 amp controllers and, by golly, that’d better be all you run through them. One still works. The first one that went bad was replaced with a Flex Max 60. Still a 60 amp controller, but it just limits the output and won’t hurt itself. After the second original charge controller smoked, he finally heeded what I’d told him about underspec’d charge controllers and overdid it, buying two of the FM80 units. That’ll darn sure handle it, but another FM60 would have worked because of the current limiting feature. It may be that he just bought the FM80s and put the FM60 in reserve for the day when the final Brand X controller expires. Anyway, read the manual (RTFM) and sometimes you can save money by not buying too small and sometimes by not buying too large.
Now here is something I like. He made his own cables and with 2 cable ties and a strip of inner tube rubber made what effectively serves as boots. You can still easily get to the bolts, but if you drop a tool, you are less likely to short anything out.
These Trojan T105s are only two years old, but the water was never checked. Ever…until it was observed that the system just wasn’t performing up to snuff. Normally, if you dry out a set of batteries, you get fuming acid toward the end, and even early on you can get some really corroded terminals. Lots of people use Vaseline or ordinary grease on terminals to help with this, but Tom used an anti-corrosion electrical grease, and boy does that stuff work! These terminals are all bare copper and there was not a hint of corrosion on any of the 16 batteries. I don’t have a brand for this, but will be checking on it. No more axle grease for my batteries!
I have harped on keeping the batteries watered on many occasions, but that is not the only battery maintenance you need to do. By the way, when the batteries were topped up with MANY gallons of distilled water, the cells were all active and they regained 50% capacity. That’s says a lot for Trojans. I suspect a good desulphation charge will do wonders for these batteries. Worth a try, anyway. But back to the other battery maintenance chore. You have to snug up the bolts to make sure they stay tight and resistance stays low. What happens when there is resistance? Power is wasted in the form of heat. Fire up the a/c and the dryer and you’ll find out just how much heat. Near the top left of the next photo you can see what a T105 terminal is supposed to look like. Then there are two that were a bit loose.
All of the nuts had washers under them, but none were lock washers. Lock washers serve two purposes, they can keep the nut from backing off, but they also provide a little spring tension. What I like best for batteries is the Belleville washer. This is dished and provides great contact pressure without over-tightening the nuts.
I don’t mean to trash Tom’s system, but it is always good to pay attention to what you should and should not do and observe the results of both. Looking at my photo of a ruined $150 battery is a lot less heartbreaking than have it happen to yours!
It just breaks my heart to turn off a working system! –Neal
I have been observing the performance differences of my west wall array and my conventional south arrays. Arrays still pick up a lot of power under cloudy conditions, but the south arrays are doing better. I think I know why.
The current situation is that the west wall will do pretty well with direct afternoon sunlight. However, it is pretty much facing a dark wall of trees, which reduce diffused and reflected sun from the western sky.
On the left of the Solar Shed, the arc of trees between the edge of the airstrip and the red line blocks the view of the sky.
If I cut some trees in that arc, it should brighten up those panels on the wall. The ground falls away very rapidly to the west, so it won’t be very many that have to be cut. Maybe a half dozen are the principal offenders.
It’s too bloody hot to do logging right now and my wood pile is already bloated, so this phase of the project will wait for winter. By then, I should have plenty of “before” data to compare to the “after” data. Stay tuned.
Have you seen the $7 solar modules on the Sun Electronics web site? They are 70 watts, so that’s only a dime apiece for a whole watt! Can they be any good???
I admit it, I am a tightwad and bargain hunter. I didn’t need 50 more solar modules, but I saw where John was advertising these solar panels so cheap and I could not resist. Apparently a lot of people have reservations about these things, because he still has plenty. I’ll tell you the good, bad and ugly bits of my experience and you can make up your own mind if they are for you.
First of all, these are first rate, name brand gear. Google First Solar FS-270 for the spec sheets. Second, they are second hand, having been removed from a school. (why were they removed????) Finally, they are “thin film” modules.
Mostly John sells poly- or mono-crystalline modules. There is somehow a perception among some folks that these are better. However, if you look at pictures of solar farms, you will see an awful lot of these very same thin film modules in use. The pros use them. Here are some general characteristics.
Thin film panels are bigger for a given wattage. Maybe these were taken out of service so they could get more watts from the same amount of space.
Thin film panels work better in cloudy weather. They respond better to the light that is filtered through clouds than the other panels do.
These are rated for 70 watts and have an output of up to 100 volts.
Thin film panels are not as bothered by leaves and bird droppings. In a water monitoring device I used to build, a leaf or a bird splat could cover much of an individual cell on the small panels we used, killing the panel. On the thin film panels, only the amount of area covered by debris was degraded.
Thin film panels are heavier, per watt. The active material is sandwiched between 2 thick sheets of glass.
They are about 2’x4′ in size, making them easy for one person to handle.
Thin film panels can be fragile if not handled properly. Well, I guess that goes for most solar modules, doesn’t it? These have no protective aluminum frame, so there are extra handling and mounting considerations.
Not all of these panels have both MC3 connectors on them. Replacements are cheap, though.
Ok, that’s a bunch of general info. I will now get into a little more detail. I ordered a pallet of 50. That’s the minimum, but you can buy a shipping container full of them, if you need more. That was the easy part. 50 x $7 is $350. Did you ever think you could get 50 modules for that? Just call Roberto or Tony and they can take the order.
Shipping is where it hurts. If you are in California it is not so bad, but to get them all the way to Florida or anywhere else on the East Coast, it will probably cost more than the panels. For some reason, crossing the Mississippi River costs extra, or it seems that way. I did not have a good experience with this part of it. SAIA was the carrier and they have an unmanned terminal in Pensacola. I showed up and nobody was home. The way that works, you show up and wait until about sundown when the drivers start returning and you pounce on the first guy who shows up to demand your load. If you live in a bigger town you’ll probably have a better experience.
Well, a driver came, I pounced and he went off to a storage trailer with his forklift and returned with my pallet. It was leaning, which I took to be a bad sign. A guy in California builds these pallets and then the truckers attempt to break them. This time the trucker won and I got, if I remember right, 13 busted panels in the lot. Sun Electronics refunded the price of the busted units, but I no longer had 50 panels. I had my heart set on 50! Well, that’s how it sometimes goes. I checked and it seems my experience is the exception to the rule.
Well, here they are. What can I do with them? First of all, I need a quick and dirty solar lighting system for my boxcar. It is really a 40′ shipping container, but it looks like a boxcar, so that’s what we call it. It is also a long black hole. I strung LED light strips from stem to stern, plugged them into a cheapo car inverter, connected that to my hot spare 200amp sealed 12v battery, which is regulated by a 40 MPPT controller from my junk box and that is wired to 4 of these panels in parallel. Remember, these things put out about 100v, so you don’t want to get carried away with series strings unless you are doing a high voltage grid tie system and you will need an MPPT controller for battery systems.
I have the greatest of intentions for mounting these panels properly after I put a seal coat on the top of the boxcar. Right now they are just up there on the roof. To complicate solar production they are not only horizontal, but they are in a deep forest where there is rarely a bit of direct sunlight and leaves are constantly falling. Sounds like a challenge, eh? That’s exactly why I chose the thin film panels for this project, because they work well in diffuse light and don’t mind a few leaves. How well are they producing? There is no way of knowing and it is hardly fair to judge them in a case like this. All I can tell you is that whenever I need the lights, they work.
I did another setup at the Solar Shed that is not only pretty conventional, but I have a recorder on it and am getting some data that I can compare with the other arrays.
I put a dozen of them on the wooden test racks below the eaves of the Solar Shed. 12 x 70 will ideally yield 840 watts. The angle is way too steep for summertime, but I can compare with some poly panels mounted on the same rack. If you are into that sine and cosine stuff, we should expect around 70% of rated power this time of year.
The first bit of advice I am going to give you on mounting is don’t mount them on a wooden rack. Wood does not seem to die until you burn it. When it is dry it will twist this way and when it is wet it will twist the other way. My clamps were a little too snug on a couple of the modules and I ended up with two more broken ones. BUT, they still work, so I left them in place, for now.
Again, there is no metal frame, so you use clamps. I used rubber-backed discs, but the original setup used flat bars that you could probably duplicate with aluminum bar stock from Home Depot. A backing of inner tube rubber would be a nice touch. It really is pretty simple. You cannot mount them on a flat surface because the junction box is on the back of the panel. Mine are on wooden rails, but I recommend you go with more stable metal rails to avoid breaking them.
Since a MPPT charge controller typically maxes out around 150v, I just wired all 12 in parallel, using a special combiner harness I built. I can plug or deplug any of the MC3 connectors if I need to troubleshoot. I have plenty of controller capacity left, but I wired up this dozen independently so I can check performance. If I decide to make a permanent thing of this, I will run the power from this array through a combiner that includes diodes so the slight voltage mismatch won’t cause trouble. We don’t want the polys and the thin films fighting.
So how are they doing? I realized early on that I was probably missing a few watts because the system would charge up and the controller would cut back. It is pretty much running all out, now, by adjusting bulking and floating points just a tad higher than the other 5 charge controllers.
So far, they have produced 57 kwh and have averaged a bit over 2 kwh per day in this rainy season with a bit of Sahara dust cloud mixed in. I have seen 3 kwh in a day. I have observed a peak power of 572 of 840 rated watts. Given the steep mounting angle, that is just about right for the panels running at full rated power! John was worried that they might have lost a lot of capacity, but they are great!
Here are some random comparisons with a 1000 watt set on the same rack.
170/840 vs. 161/100 under overcast conditions.
439/840 vs. 400/1000 hazy
69/840 vs. 71/1000 very late and cloudy
345/840 vs. 320/1000 at 1pm under hazy sun
As you can see, the thin films sometimes outperform the larger poly array! I am betting the poly will do much better on the cool, clear days of winter.
I will continue monitor these panels for a performance update.
Conclusions? You’ll need to treat these a little more gently than framed panels, they’ll take up a little more space and they’ll cost a little more to ship, but with their handy size they are great for a DIY’er. You should be able to put together a first rate solar power system at a rock bottom price.
There are good deals. There are bad deals. There are scoundrels who will try to tell you their bad deal is good. If you don't want to deal with all the razzle dazzle in solar power systems, do it yourself and you will know exactly what you have.
It is a weather-tight box that combines the outputs of a number of solar panels before sending the power to the next level of equipment. It can be simple or very elaborate. I was recently looking at them for a project I have.
Solar panels are sometimes used as singles in parallel or in multiple series strings. Running a wire from the roof or backyard from every one of those panels or strings would use an awful lot of cable and it just isn’t necessary.
For example, I am going to review some of these super cheap $7 thin film panels John has for sale. I had room for a dozen of them come available on my test rack, so there they are. These panels can put out nearly 100volts EACH, so you can’t really string them together for a typical 150v MPPT charge controller. Obviously they were meant for string inverters, but if you are going to be a tightwad like me, you have to be creative.
So what I am going to do is run them all in parallel. Because they are high voltage output and only 70 watts, they are going to make less than an amp each. That means the power from all of them can come back to the control room on a single 10 gauge solar cable. THAT is where the combiner can come in handy. We have to get all 12 pair of wires connected to one pair of wires.
Some combiners are super simple, consisting of just a weathertight box (because this is out in the weather with the modules) and some barrier strips to connect the wires. Some take it a little further and add a fuse for each panel or string. You can even put a surge protector in there. Rooting around on the Sunelec.com website, I noticed one he had has a little bit of DIN rail in it, so you can clip on all kinds of different options.
Some have built in MC4 connectors, the most popular type. These cheapo modules use the older MC3 connectors like my shingles. You don’t see them much, anymore, but there was one combiner box that even had long pigtails spaced for running directly to the modules. Handy, but not cheap. Well, maybe it is cheap enough. Sure, this is not rocket science and you could probably build your own combiner boxes, but by the time you source and purchase all the bits and pieces and then wait forever to get the bits and pieces, you can see that maybe it is well worth the price. Using a combiner box will give you safe and durable connections.–Neal
A Cultural Resources Management (CRM) firm recently had a question about an old water-powered mill in our county. You don’t think much about water power in a state as flat as Florida, be we had lots of them. US 29, through Escambia County, could have been named “Industrial Boulevard” there were so many. The firm contacted the University and the query was forwarded until it got to me. I worked on the mill survey a couple of decades ago and am a go-to guy on mills and local history. That query led me to look into the history of the family that owned it. I discovered on a genealogy site that they had a cemetery and nobody knew where it was.
That struck me as a challenge, to find the cemetery. It was an exercise in armchair archaeology, followed by a trip to the field…a fun activity during lockdown, as I’d only be around dead people. I found dead people, thanks to Lidar topgraphy mapping.
There were depressions in the ground, indicating 3 graves. Genealogical reports indicated there should be 3 graves, dating from 1825 through 1849. The family had come here in 1819, when Pensacola was still a Spanish colony and they were prosperous planters.
The graves had been marked with wooden markers. I found bits of pine knots, but nothing that would indicate who was in which grave and I was curious about that. Could I properly determine, by non-invasive means, which person was where?
Mary Ann, the matriarch died first. Then her grandson John. Then John’s mom, Lucretia. I have dates of death for each and when I return I should be able to determine who is where!
How, you ask? By the angle of the sun. Everybody knows the sun rises over there and sets over yonder, corresponding to some variation of east and west. Once you get a solar array, you start noticing a little more. For example, right now, in June, the first and last rays of the day are on the BACK of the Solar Shed! A fat lot of good that does. The sun isn’t moving in a straight line. It travels in an arc. In winter, that arc swings further to the south, beginning and ending closer to actual east and west. The nature of this arc will vary according to where you are.
Now back to cemeteries, most cultures will plant you in an east-west orientation. Modern cemeteries have very precise placement of graves, making things very compact and tidy. In the older cemeteries, sometimes charted using ground-penetrating radar, you’ll see some variation, with the direction of the feet swung a little to the north or south. That is because burials were aligned with the sun and not a compass. Therefore, I should be able to get the angle of the sunrise on a given date and match it to a particular grave. I think it is a pretty sure bet that Little John is between Mom and Grandma, so the real question will be who is on which end. I can’t wait to get back out there and take my measurements.
There are websites and apps that can calculate and display the sun’s arc for any particular time of the year, in case you would find such info handy.
But back to solar power, alignment of the solar panels can make a big difference in your power production and your best angles might be determined by how you use your power. Mine are pointed southward at roughly the same as my latitude, a general recommendation and they perform very well in the winter when the sun is lower and more southerly. I don’t use as much power in the winter because I have a wood furnace and do not use the heat pump. I could use the heat pump to save wood, but I have more wood than I can possibly use.
In the warmer months, the sun is not straight into the panels at noon and it spends a couple of hours shining on the back of the shed. I would be better off with the panels just flat, like on my boat.
Expansion plans for the Solar shed include another 32 feet off to the west, using active panels/shingles, and a carport on the backside for golf cars and lawn mowers, using dead shingles. Now I am rethinking this. Maybe put the dead shingles on the south roof, because I have plenty of winter power, and live shingles on the north carport roof to capture the early and late rays. Maybe the guy whose house is featured in John’s Blog had the right idea.
Yeah, I like that idea, but what is immediately obvious is that solar modules are the wrong shape. They need to be in a keystone shape to maximize the panel area on the roof!
Of course, if you are ground mounted, you can use a tracker. These are available in single and dual axis form. They can be very expensive to buy and install, which raises the question: tracker or more panels? The big boys, who do enough of this stuff to know go both ways. It may just come down to available space. Most of the commercial farms that I have seen with trackers use a single-axis system. That just swings the array from east to west and should make a very big difference.
My own array makes plenty of power, but not necessarily when I need it. I could get by with a smaller pile of batteries, I suspect, if I could put more of that hot afternoon sun directly into my air conditioner instead of on the back of the shed!
This fall, I will be helping my friend Courtney with a new tracking array installation in North Carolina. Stay tuned for a report on the installation and the performance.
Now about that family that misplaced their cemetery, the bulk of them moved to Mississippi in 1836 after planting had depleted the soil here. John Sr. followed later, after Lucretia died. After depleting the soil at their Mississippi plantation, they moved to Texas and guess what? They forgot where they left the Mississippi cemetery, too! They are on their own finding that one.
Fuses offer cheap circuit protection, but there are some precautions you may need to take.
The H-Bridge locked up on my inverter recently. It blew a fuse. It blew it with a lot of self assurance, too. There was no dilly-dallying. Never mind what an H-Bridge is, but in this case it can handle 1200 amps, so when it locks up, something bad could happen. That’s why there’s a fuse.
Usually, you kind of work your way up to blowing a fuse. The load exceeds the rating, the metal melts and everything stops. When you get over 1200 amps trying to get through a 150 amp fuse, you get a plasma bomb. The blast made a perfectly round hole in the mica window that is there to contain the failure and then it blew the plastic no-finger-pokey cover across the room.
The wife says there was lightning and then stuff didn’t work. So, you think maybe it blew a fuse and you go to replace it because you don’t know you have a locked-up H-bridge. You are careful because all of those capacitors in the inverter make a good pop anytime you put in the fuse. What happens, though, is not a good pop. You get a major arc that burns away part of the fuse holder and part of the fuse. Then the link BLOWS with great vigor, leaving you with black fingers. Being the cautious type, the fingers were on the protective casing of the fuse instead of over the window where the blast originates. The moral of the story is to be careful installing a new fuse.
There are different kinds of fuses for different purposes. Used to be only “T” fuses were used with inverters. I have used them when that is what I had, but they are very expensive. One thing I am pretty sure of, they would be hard to explode. Many cartridge fuses are filled with sand to contain and dissipate any excess energy they might encounter. I like ANL fuses. They are effective and dirt cheap. They are popular on boats and that is my upcoming primary wiring projects as I build the two Solar Yachts. They are not that good at containing plasma balls.
A disadvantage of cartridge fuses is that some holders can lose their spring tension and the connection can get a bit resistive, risking fire. For that very reason we had he circuit panel replaced at Mom’s house about 20 years ago. It was getting hot and smoky! Both the T and the ANL fuses are firmly bolted into place.
Whichever you choose, take care when inserting a fuse, especially when power is present. Remove the power when possible. In this case, there is going to be a pop somewhere. I would rather it be at a fuse holder than at the big plastic box full of explosive hydrogen (the battery).–Neal
You know, the time when you do your preventive maintenance.
Unless you have sealed AGM, Lithium or other such batteries you need to check the water at least once a month. Even if you do have sealed batteries, there are other things to check.
Back to the water, this is a rehash, but in case you missed it, keep a supply of distilled water and a box of baking soda handy. A rubber apron, gloves and safety glasses should be in your kit. Oh, you’ll need a wrench and a plastic funnel, as well. Keep the water up to the split ring. Use the baking soda to neutralize the acid that accumulates on top of the battery.
Make a note if a battery or cell uses more water than the rest. That battery may have a problem. If water consumption goes up all around, you could have a charge controller problem. I had a charge controller kill some fairly young batteries, so I know it can happen.
Keep the batteries clean and dry. After a washdown with the baking soda, give them a good wipe or they will be white and crusty from the soda. I find that a blow nozzle and compressed air can make cleaning a breeze, but not everybody has their batteries where they can get away with that.
You may need to clean the terminals, too. Acid fumes leak around the terminal posts and can make a mess of things. This can cause resistance, heat and wear on the terminals. Wearing safety glasses, I use a fine rotary brush in a cordless drill to scrape off the crud and polish things back up. A dab of Vaseline or even axle grease on the terminals and posts can help limit a recurrence. Since you may be stirring up some lead dust, you might want to add your Covid mask to your safety gear. Replace or repair cables, if needed.
Even if your terminals are all clean and shiny, take a wrench to them. You’ll be surprised how they can get loose. I was at a guy’s house the other day. He isn’t big on maintenance and as he began his biennial battery check it took gallons of water to top the Trojans up and the terminals would spark under load because several were loose. Batteries need water because they turned the old water into explosive gas. Do you really want sparks around that??? Don’t wait two years to check this stuff. Batteries should last longer than two years, but not if you don’t maintain them.
My electric jalopy gets checked monthly, but it lives a hard life and had one terminal loose and two that were getting right colorful with corrosion. It does not take long. On the other hand, my boat uses an identical battery set and there are rarely issues with it. The difference, I think, is that the boat is a much cleaner environment. No dirt to accumulate with acid. The jalopy got its batteries cleaned, but with the work it does it will soon be a mess, again. Both the boat and the jalopy are part of the solar power storage. Despite the hard use, the jalopy batteries are pushing 6 years of service.
In the area where you have your charge controllers and inverters, you won’t likely find any corrosion, but those cables get loose, too. I keep the appropriate tools right there at the control panel so I don’t have to go hunting down the right Allen wrench or crescent wrench or screwdriver. Infrared, non-contact thermometer guns are helpful tools for a number of occasions in the solar biz, including checking terminals for poor connections by looking for heat. Yes, you can use a finger to detect heat, but there are places I personally don’t care to stick my fingers!
I have one set of batteries in one of my experiments I need to get to because it looks like a cat peed on them. I’m not really looking forward to cleaning that up. I can’t really prove it was Smokey, my big, half-wild tomcat, but he HAS been walking funny, lately. Add that lesson to your list of safety rules: Never pee on a 48 volt battery pack.
They keep changing the rules on grid tie. Avoid dual meters, special fees and changing deals by mixing your power with that from the power company, without backfeeding to the grid.
Many years ago, a fellow came up with a gadget he called a synchronous inverter. Today we call it a grid tie inverter, and it changed everything. It allowed you to mix sun power DC current with the utility AC current. If you were using a heavy load, the solar power would replace some or all of it. If you were not using much of a load it would flow out through the meter, spinning it backwards to reduce the power bill. As long as you used a little more from the grid than you made with the solar, things were ok. This was called guerilla solar.
If the power company came by to read your meter and got a negative number because you made more power than you used, well that is when the trouble started. Some power companies forbid you to do grid-tie, some encourage it, some pay you to do it, some make you pay dearly and they’ll pretty much all require some special equipment. Your mileage may vary. Check with your local power company before you start.
My friend Courtney got lucky with his system. He lived in South Carolina where they actually paid him to add solar, plus he got Federal tax credits, so the whole thing came out pretty much free. There was a price to be paid in paperwork and jumping through hoops. He and I did the work, but he had to have a licensed electrical contractor and a NABCEP solar installer inspect the work before it could be commissioned. He also had to have a mechanical engineer sign off on his pergola being strong enough to hold the panels. It was strong enough for all the panels and the two old guys putting them up there, but it had to have the engineer’s stamp of approval. There was lots of paperwork.
On the other hand, there’s my power co-op that throws up every obstacle to grid-tie. I know of three people who have done it, but I can’t see where they are saving much. Others have had their power companies welcome grid-tie, only to change the rules later and jack up the fees.
Being the rebel I am, I have spent about a year studying how to use your solar power and not get the power company involved. One lovely way of doing this, used by Tom, is to use a grid interactive inverter. These can usually do grid-tie, but can also provide standalone power for use if the grid is down. During the day, Tom’s array charges his batteries and they feed the DC to the inverter that makes the AC. The inverter also has an input from the grid. As long as the batteries have plenty of power, the house runs on solar. Tom uses loads of power. Computers, TV, lights and coffee pot are always on. The inverter lets him select just how much he will draw from the batteries. He sets a fairly shallow draw to give the batteries longer life.
To accomplish this, Tom has a “generator plug” and a transfer switch. There is an actual diesel generating setup, but for everyday purposes, his solar system is the generator. So, a grid line goes to the inverter and the inverter runs the house. At night, the A/C will drag the batteries down pretty quickly and the unit automatically switches to grid power. If a hurricane takes out the grid and blows away the solar array, he can fire up the generator and charge the batteries with it or run directly into the house.
Tom’s stuff is not grid-tie, though. Courtney brought over a pallet of LG 300 panels and a case of Enphase microinverters and challenged me to see what I could come up with for operating an air conditioner from solar. No problem, except that I can’t do grid tie.
I played with the microinverters on my off grid system, which goes to my “generator plug” to see how far I could push it without a visit from the big white truck. I figured a plan and calculated how much my A/C compressor used and selected enough panels and micro inverters to match. The output of the microinverters went underground to the MOTOR SIDE of the big contactor under the hood of the A/C. When the A/C comes on, the microinverters are energized and they connect sunlight power to the cooler. Success!
Limited success, I should say. By Federal law, the microinverter has to wait 5 minutes before it does its thing. If you have a short cycling A/C, then that is a problem. Most HVAC contractors oversize their gear, but in my case I have a system for upstairs and a system for downstairs. The smaller upstairs unit is only 1.5 tons, but it keeps the house comfortable downstairs, if a bit chilly upstairs, while running nearly constantly on a really hot day. In this configuration it really saved a lot on my power bill and I had the house a lot more comfortable than if I were buying power. Best of all, I did not have to deal with the power company.
So here are the limitations. We are only saving power on the A/C, we are saving nothing at night and very little on cloudy days. Can we improve on that? Why, yes we can! It turns out these particular Enphase inverters have a form of limiting in them. Though they are being fed with 300 watt panels, they can only feed a bit over 200 watts into the power line. That isn’t as kookie as it sounds. It sort of levels things out when the clouds pass. It also means you can connect batteries to the microinverters and use the panels to charge the batteries through charge controllers. These micros are designed to operate from 60 cell panels, so a 24 volt battery bank works fine as a feed. Now the microinverters can microinvert at night or when cloudy, within limits of course. We saved even more on A/C.
Can we do better? Is there a way to feed the power to the whole house without spilling any out the meter? Yup!
So I ripped out all the microinverters and started over. First, the panels were arranged in series pairs and the DC was sent underground to the “dog house” next to the A/C units. In the dog house, two Grid Tie Interfaces, Limiter (GTIL), sometimes known as Zero Export Grid Tie, were installed, each plugged into a 110 plug from each leg of the 220 line. Some of you may be thinking, “Hey I’ve seen those blue boxes and they make one for 220. Why not use that one?” There’s 220, Euro style and there’s 220 American split phase. The bigger blue box does not understand the American Way.
Anyway, you plug these GTIL boxes into 110 outlets, add solar and, voila, grid tie. But not limited. You’ll get the visit from the big white truck and probably quickly if you have a smart meter. It’ll call home and you are busted! However, there are sensing coils that go in the big gray breaker box. They can sense if the power is coming or going. With the sensor coils in place, turned the right direction and plugged into the right box, the solar power will come rushing into the house wiring, filling every light bulb and small appliance, but when it tries to squeeze out toward the meter, the sensors stop it in its tracks, leaving maybe 4 watts coming from each leg of the utility.
In my case, the boxes are called “1000” units, but actually rated at 950 watts each. That may be a bit of an exaggeration. Still, under ideal conditions, they will handle most of the background load, but get overwhelmed a bit when the clothes dryer or oven are used. The dryer, for example uses 5000 watts, normally, but if the GTIL pair can knock 1500 watts off that, then that adds up to some savings.
Let me interrupt for a moment, in case you are thinking of getting some of these wondrous boxes. If you already have a grid-tie system, it is quite possible that adding a simple gizmo will allow you to do the same tricks with your existing gear.
Back to the GTILs I use, am I perfectly happy? No. For a couple of reasons, or more. First of all, the two inverters are connected to the same solar array. Solar panels are a somewhat high impedance source of power, which is to say that when you put a load on them, the voltage goes down. If one of the boxes is providing 800 watts to the coffee maker and someone starts up something substantial on the other leg, the solar source voltage drags down a bit further causing the first unit to trip out while the second tries to take charge. Before you know it a full-on fight ensues and nobody is contributing power. Sometimes both inverters will settle down in harmony and then a puffy little cloud goes sailing by and everything trips out again. Can this be fixed? Yes, to some degree, by simply dividing the array into two separate branches. The thing is, the solar panels are 200 feet from the point of use and digging trenches and pulling expensive cable is a bother. No, it isn’t quite as dire as that, in truth. I do have several cables in parallel that could be separated, but I have bigger plans, so no use getting involved in wrestling with heavy gage wires.
The next phase of the plan is to add batteries. Again, we will have power available around the clock, as we did with the microinverters. Batteries are a low impedance power source, so the two GTIL units should not fight.
The next step took some time to complete because I needed batteries. I looked far and wide for just the right batteries for my Solar Yacht project with the idea of running the house on them as a test and putting the old batteries, Sun 230s from Sun Electronics, on the GTIL project. Batteries, cash and opportunity converged and I had batteries.
The lines from the solar panels, LG 300s, operated in parallel pairs, for a total of 2400 watts, were disconnected from the GTIL units and reconnected to a 60 amp MPPT charge controller I found in a drawer. The output of that was connected to terminal blocks with connections to the battery and the GTILS. Oh, yeah, there were some fuses, circuit breakers and a surge protector thrown inline for safety. It worked.
Then Courtney wanted his panels back, so I put up a kilowatt of panels from a boat project. Less power, but since they were charging the batteries there is usually enough. Now the only limitation is high usage on a cloudy day, but isn’t that always the case?
Now the batteries can run loads any hour of the day or night. Cooking on the stove top? Covered. Electric clothes dryer? Knocks off nearly a third of that. Washing machine? Covered. Baking blackberry cobblers? Uses only about 1 kwh from the grid for a 5000 watt oven. There were two mystery loads that showed up on the monitors. They turned out to be a fridge and a freezer that had been left on the grid. They have been moved over to the all solar system, but they were being covered by the battery GTIL.
There was 72 kwh use from the grid this month, about half of last month. I had projected that it would only be 50 kwh, but in the corona lockdown, my wife deals with the situation by doing laundry. Many more hours of dryer time are being consumed than are actually needed, by my calculation, but my calculations don’t seem to count. I keep quiet about her laundry obsession and she makes me cobbler. I don’t mind losing a kwh to get a bowl of cobbler! The limited grid tie took care of an additional 67 kwh. The grid tie solar would have provided more power, but about the 6th day I discovered I had an unexpected load of a fridge and a chest freezer that had been overlooked. They were moved to the main solar circuit so they would be left running if the grid went down. They would have used another 72kwh from the grid tie.
OK, so if I have explained this properly, you may be wondering how you can get some of this limiting grid tie stuff, am I right? If you already have a grid-tie power system, you may be able to add the limiting system.
Most GT systems have an optional power monitoring module available that will allow you to keep up with your power use and grid interactions. Some of these have sensing coils available and they have the software to convert to limiting operation. Check your manual. It’ll probably be a very small mention. I know that SMA/Sunny Boy has a power meter accessory that can do this. Elgrispower.com has one they claim works with about a dozen different grid tie inverters.
No, if you are running a 600v string inverter system, you probably don’t even want to think about running batteries. If the power company decided to charge you a lot of money to connect grid tie, you can be rid of that nonsense because the power is being mixed in your house and never going out to join forces with their kilowatts.
If you have net metering or some arrangement that is satisfactory, then never mind. If your power company is trying to discourage solar and jacking up your bill with fees, then this could be for you. It is the rebirth of guerilla solar and may be just the thing to save you some money on your power bill.–Neal
No, DIN does not equate to a cacophony. It means for German Institute for Standards, or National Standard, bearing in mind that Germans spell things differently than we gringos do.
There’s all kinds of DIN stuff, so it isn’t just rails. DIN rail is a metal rail, usually aluminum or steel, about 35mm edge to edge and pretty much as long as it needs to be.
I first saw it in industry, where programmable controllers and other handy gadgets were mounted to control manufacturing processes. DIN rails and handy gadgets are great for solar, too. I buy short lengths of it on ebay, usually by the fistful. They are only a buck or two each, so that appeals to me. Then there are the handy gadgets. The items most used are fuse holders and circuit breakers, at least in my work. I saw a very nice combiner box the other day that was stuffed full of fuse holders and terminal blocks, all hung on DIN rail. Very nice.
I have bits of DIN rail here and there to store spare parts where I can find them. Look into them and see if you can come up with uses for them.–Neal
It looks to be heading to Louisiana, but Florida is getting the bulk of the rain. As far as storms go, this should be pretty mild, but you never know what tornadoes might pop up. Driving could be tough. Trees can fall on power lines.
Hopefully, those of us in the storm zone just get some soaking rains and our solar power will keep the lights on and set an example for our neighbors to follow.
Ok, you know I like to talk about safety, often based on experience, so here is a quick one I bet you haven’t thought about.
I am planning to try some of those 10 cent FS70 solar panels that Sun Electronics is selling and then write a review. I have actually used 4 of them in the lighting system in my “boxcar”, a 40′ boxcar-red shipping container. At the Solar Shed, some space freed up in my test rack, so I reconfigured for these modules. Next step was to fetch them and try them on a larger scale.
They are not big, but they are heavy, so I move them only two at a time. With one pair on board the Solar Yamaha, I went back for another. I am very careful with these as the panels can put out about 100 volts and some are missing the MC3 connectors, exposing bare wire.
So I curl my fingers around the corner to tip it toward me–there should be no wires at the corner–and, OMG!!!! 100 volts, my hairy hind end! It was more like 10,000 volts! I fully expected to see a charred nub where the finger used to be, but, no, there it was, all pink and healthy-looking, even if it did still feel like it had a hot nail driven through it. What the heck?
Then I saw the wasp fly out from behind it! Great! One more thing to worry about. If there is a moral to this story, it would be to watch out for Mother Nature. She is a practitioner of Murphy’s Law. Look out for wasps behind panels that have been leaning. Black widow spiders like to live under things on the ground. Don’t overlook the possibility of a snake or a scorpion under a pallet. It’s always something, isn’t it?
For a day or two, I went around with a hand that looked like those big foam “we’re number one” hands that people wear at football games. I learned a lesson I won’t forget and I am admitting to it so maybe you won’t have to learn it for yourself.–Neal
In it was a handout touting the cooperative’s dedication to service to its members. The coop power had been out for over 3 hours at that time, owing to a car vs. pole incident. A neighbor had power because I could hear the generator buzzing. I had power, too, but nobody could hear it.
Back to the power bill. I have been waiting for it with glee. How often to you hear of that? Pretty often when you are dealing with people who enhance with solar.
This was the culmination of efforts on one of my latest solar experiments. I have done a writeup on the whole deal, but I just thought I’d show the power bill first. $50. There was a time when I would have thought that was terrible. $9 of it was for electricity and the rest of it was….terrible. Fortunately I “don’t have” grid intertie, or they’d tack on another $50 service fee.
What I have done is put the “generator circuit” and a/c completely on solar. That left the big stuff. I added a limiting grid-tie apparatus that helped during the day, but it wasted a lot of power fighting for the solar. The latest revision is battery enhanced grid-tie. It works all day, all night and the two units never fight. This is what happened to the bill.
The reason any use showed up at all is that the oven and the clothes dryer each run at about 5kw and the little grid tie units I use are only good up to 1900 watts with the sun shining and a bit less at night. Several blackberry cobblers were baked last month, running up the power consumption, but well worth the expense of about 13 cents each. I’ll release the full story on this project in a day or so.–Neal
Last week, during my morning coffee and internet infusion, I read of a very large solar power plant being planned for Bureau of Land Management (BLM) land in Nevada. Then, this morning, I read about a 6.5 earthquake in Nevada. Man, it’s always something going wrong, isn’t it? Then I heard Puerto Rico had one!
It just goes to show that normal, everyday conditions are not the only ones to plan for. Here in Florida, we don’t get a lot of earthquakes. I recall a rattle or two, but nothing like the 1781 quake of 6.5 recalled by Chaplain Waldeck of the German mercenaries who were defending Pensacola from the Spanish at the time. That was enough to crumble chimneys and knock barracks houses off their foundations.
I wonder if there are special design considerations for solar in earthquake zones. Years ago, when I was providing management systems for distribution warehouses around the country, I notice that most had steel beams. However, in earthquake zones in California, Washington state and Alaska, the beams were wooden, because they would flex.
Most solar installations I have seen use galvanized steel posts or beams. Put a heavy mass of panels on top of that and the mass will try to stay fairly still while the poles take the shock and perhaps bend. I’m thinking there needs to be something springy or slidey involved in the mounting. I think I will look into seismic mounting to satisfy my curiosity.
Here on the Gulf Coast and up the East Coast, we have hurricanes. Forecasters were talking this week about a storm already forming and there was a weak swirling mass that went through Miami and is now crawling up the Atlantic coast as a tropical storm. Call those a warning. It is time to prepare NOW.
We have a long history of hurricanes here in Pensacola. Juan Tristan de Luna y Arellano and friends sailed into the bay in 1559 to set up a colony. A few weeks later they were holding onto trees for dear life while their ships were being bashed to bits in the shallows. Bienvenidos a Florida, amigos!
Despite this long history with hurricanes, people tend to forget the lessons. It has been maybe 15 years since we’ve had a good one, here, but we have had some whoppers on either side of us. Trees grow up along the powerlines and even a mild storm can knock the grid down for a while. Trees are tough on a roof, too. When hurricanes Erin and Opal came through, the stronger one did not cause as much damage as the first because the trees had already been taken out. The last big storm that came through was so strong it didn’t need any help from trees because the power poles blew over. When Hurricane Michael came through just east of us, it blew pretty much EVERYTHING over.
A battery backup system can help keep the lights on during and after a storm. The 2500 watt system I had back during the storms helped keep life fairly normal in the 5 weeks before the power company made it to our street. A daily top up of the batteries with the generator kept things going without the noisy generator running 24/7. NOW is the time to act if you are considering backup. John’s guys already have some package plans, so it isn’t a big deal to get moving on this. My house was wired for this from the beginning, but any good electrician can retrofit this stuff, if you can’t do it yourself.
And what if you have solar power, already? Is it grid-tie-only or can it provide backup after the storm? A LOT of people who start out with grid-tie regret that decision when the grid goes down. There is equipment that will let you have it both ways! Maybe what you already have has an option you are not using. Check into it!
What about your precious solar array, assuming you have one? The Rocky Mountain Institute has a free report on what has been known to fail and what holds up against a storm. Find it. Read it. Essentially, use strong racks and use bolts instead of sheet metal screws.
In my own case, I know I have vulnerabilities. The solar shingles that Sun Electronics gave away are only rated for 60 mph. That worries me. That can be improved upon, but is way too much work. Additionally, I have a number of other modules on temporary racks. Steel stakes driven into the ground help anchor the wooden racks, but the panels are held on with screws. All of these panels I plan to remove and store in a safe place until after a storm blows over. Assuming Sun King, the solar boat, survives in its shed, it can come out and connected with the stored panels provide thousands of watts of solar input and its 5kw inverter can keep necessities running in the house. That’s the plan, anyway.
What else can you do to plan? Have some water stored for drinking and maybe a plastic garbage can full to use to refill the toilet. Kitty litter and a 5 gallon bucket can serve as a toilet if there are unpowered lift stations involved. There are ceramic water filters, like the Berkey, that can clean up pretty much any water source or you can make a purifier with a ceramic filter kit from ebay and a couple of plastic buckets.
You need access to food. The virus situation has shown us how vulnerable we are there. Normally Walmart sells a 2 or three day meal package in the camping department. Sam’s Club will deliver a one year supply for the whole family, but right now you have to get in line. There are many options for camp stoves, including those that do not require commercial fuel, but if you have backup power, a microwave and a coffee pot you can prepare all sorts of meals. Yes, you can make pancakes in a microwave, if you know the trick! A single “burner” induction plate would be a good tool in your emergency kit. (My bro was camping at my place last week and used one plugged into an inverter to make breakfast.) Commercial MREs don’t last as long as the military stuff. I have cases of GI MREs dated 1984 that I would still eat in a pinch. Under normal circumstances, you could buy a big sack of beans and another of rice and be fine for a while. Cheap, easy foods seem to be in short supply, these days, but they can be found and it is best to set aside a bit for a stormy day.
You can’t prepare after a storm and supply chains are already strained with the pandemic, so get busy!–Neal
I read online solar news journals every morning while the coffee soaks in. Most of it is grid stuff, but those guys are in it for the money and have the bucks to pay for the research, so I pay attention.
I also paid attention when I lived very closely with my solar power during my 44 days aboard Sun King. What I learned there was that we waste an awful lot of solar potential. I had 1620 watts of panels, which is not a lot when you consider that it provided motive power, lighting, cooking and, most importantly, coffee. However, sitting there all day, arm’s length from the meters, I could see that by 10 or 11 a.m., the batteries were usually topped up and less than half of the solar power was being used to run the motor. The rest went unused.
I mitigated this, somewhat, by changing my load/use strategy. After about the first week, I’d get underway about 5 a.m. to burn off some of the 350 a.h. battery storage I had. That got me further up the river each day, typically around 50 miles and up to 100 miles, and I got to use more of those kilowatts shining down.
At home, I see much the same thing. By the time I get up and out, around noon, the batteries are often topped up or at least in bulk charge. The air conditioning season is beginning to make a seasonal adjustment to the load pattern. The house a/c starts up around 0930 and the man cave a/c in the Solar Shed starts around 10. I encourage my wife to use heavy loads, like the dishwasher (1kw) and cooking (separate solar hybrid, there) during the sunny hours. She baked me a blackberry cobbler this morning! She’s ok.
I honestly don’t know how many kilowatts of solar I have available right now, but I do know that I am not using all of it on a sunny day. I also know that when it is cloudy, I don’t have enough.
So back to the grid guys, that’s where the big money is and they keep coming up with bigger batteries and cool new gear. One battery beginning construction is rated at 100mw for utility backup. That is not mwh, that is mw output. Furthermore, it is rated to run for 150 hours at full output. 6 days at 100 MILLION watts! If you know the math, try calculating the number of John’s Sun 230 batteries you’d need to match that. Furthermore, the new chemistry of that battery uses water and air! Tesla has provided some pretty sporty lithium grid batteries in Australia, too.
All of this work is leading up to solar providing more power this year than coal. They can do this because they’ve been building an awful lot of solar AND they have been figuring out how to not waste it and continue using it after the sun goes down.
A new study from Wartsila (I’m sorry, but that name just conjures up an image of the offspring of Godzilla and a warthog) suggests the ultimate setup for the grid is to install 4.3 times the peak load of solar in sunny areas, with 4 to 10 days of storage. That may sound a bit extreme, but a utility can’t compel you to do your heavy power use only during the day, or even to be conservative in your consumption.
In looking at my own system, I have always tried for 4 days backup, though my ever-increasing load makes it closer to a single day if I maintained all loads and the sun didn’t come up. I’ve nearly 800 a.h., now and plan to add another 440 a.h. soon. That’ll give me nearly 60kwh of battery, but, of course, that’s only 30kwh at the usual 50% drawdown limit. I’m sure that won’t satisfy me, either, nor will it meet the Wartsila guidelines.
As far as meeting their guidelines on solar input, my inverter was tripping above 5500, so let’s say my current peak is 6kw. By their formula I should have 26 kw of solar input! Yikes! You guys will have John’s crew really hopping if you all install 26kw of panels! Or more. My best guess is that I have around 13kw actually running. I know I have two strings of around 720 watts each that are not working and maybe that much more up, but not connected pending the construction of the final bay of the Solar Shed. Just sitting in piles I have another 5 or 6 kw of panels that I have not nailed up, yet, but it seems I can get pretty close to their goal when the project is finished. My shortfall can be mitigated by not running street lights and traffic signals all night.
So that leaves batteries. Someday we should see all of this utility battery development trickle down to the solar homeowners. It is already, really, with the drop in lithium prices. At the present time, what I see is the cheapest entry into storage is the Sun Electronics Sun 230. Best bang for the buck, if you have the upfront cash, seems to be the SimpliPhi lithium. They are pricey, but should outlast you. Ask Roberto about them.
How does your system stack up to these new guidelines?
I told you the other day I had reached the limits of what my homebrew 5500 watt inverter could do. I had a 10kw driver module to install, but it was bigger and was going to need some more cables.
One night I switched the house to grid, ran a power cord from the Sun King for lights and I shut down the inverter for a recon. What I found was that I could use what was in there, but I need to add some cables because a 10kw inverter eats lots more amps than a 5kw unit. I made measurements and notes and buttoned things back up a threw all the switches. Next day I built cables.
John likes me to talk about the basics, so here was a perfect opportunity. If I were building this inverter from scratch, I would use four parallel #6 cables because they would add up to plenty of current and wire that is easy to bend.
I promise we’ll eventually get to the fun stuff, but we gotta do the book learnin’ stuff first.
Let’s start with the cable itself. I’m talking power cables here, for high current. These are cables you might use to join batteries or to go from batteries to inverters. How big do you need? Well, I want to run a 10kw inverter on 48 volts, so it is easy to find out how many amps. 10,000/48= a bit over 200 amps. NOW the question is what size cable do I need?
Look on the internet and you can find ampacity for various gauges of copper wire. I don’t like most of these charts because they relate more to how many amps you can get through the wire without melting the insulation or starting a fire than how much is safe, practical and has little resistance. I have a memory trick I use to come up with numbers I like. I can remember the common household gauges of 12 and 14. You use 12 on 20 amp circuits and 14 on 15 amp circuits in the house, though 14 gauge is banned in some places.
Wires and cables are typically even numbered and if you go down two even steps, you double the capacity. So going from 14 to 10 you double from 15 to 30 amps and from 10 ga. to 6 ga. you double it again to 60 amps. Some charts will say 6ga. will carry a lot more and it will, but it will get hot and drop some volts. If I were making a long cable, I would run less than 60 amps in 6 ga. cable. It boils down to USE A BIG ENOUGH CABLE. Or enough little ones.
But wait! Why am I building 60 amp cables when I need 200 amps? If I went with 4 60 amp cables, filling up all the terminals, I’d be good for 240 amps. No problem.
I’m not going to make it that easy, because the negative line already has a good 2 gauge cable. That’s two steps down from #6, so we double again. That’s a 120 amp cable. Adding my two 60s and we have plenty of amps.
Regardless of whether any of that sank in, we are going to build 6 gauge cables today, because that’s what I need for my project. My favorite cable for this is marine cable. It is fairly tough, very finely stranded and flexible and every strand is tinned. In some cases you might be required to use cable that is UL listed for solar applications. If you are wiring inside your inverter or making cables for your golf car batteries, then use what works for you.
What do we need? Wires, terminals and tools. I have a roll each of black and red #6 cable I’d bought for something else. Having both black and red makes it pretty obvious which is for positive and negative. Here’s a tip, bolt cutters make great cutters if you have a set just for cables. You won’t be happy if you cut the bolt first.
The inverter module came with some terminals that have foldover tabs. They are not my favorite, but they were free and they fit the screws. I also have some heavy duty tinned terminals, too. Terminals, by the way, are sold according to wire size and stud size. Putting #6 wire in a terminal made for 00 gauge wire is not a good plan. Match your terminals to your cables. It’ll mean having more terminals in the bin, but will make for better work.
You’ll need some pliers to bend over the tabs on the copper terminals, but don’t think that makes you done.
You need a crimper tool. Some look like bolt cutters, except they crimp instead of cut. I have a couple that are like little presses that hold the terminal in place while you give it a couple of whacks with a big hammer.
The tool I use works best when it is sitting on an anvil. My shed anvil has gone missing. There’s one over near the barn, but that’s a long way and it is heavy. Today, we are substituting the stump of an oak tree that dared to extend a limb over my solar array. Take that!
An anvil works better. Last time I lost an anvil I found it with a bush hog. That wasn’t good.
Back to tools, you’ll need a sharp knife. Keep it simple. I use a sodbuster and a lot of electricians use Barlows. A butane mini torch is very helpful for soldering. You’ll need a roll of solder, too. I like old fashion 60/40 rosin core. Never, never ever use acid core or stuff from the plumbing department. A good collection of shrink tubing is very nice to have for professional results.
Here we go, now. Determine how far back you need to strip off the insulation. Use the knife to go around gently, getting through the insulation without cutting the wire strands. For the open terminals, take pliers and bend over the tabs the best you can to hold it in place. On the tube terminal, just slip the cable in, making sure you get all the strands in.
Next, put your wire and terminal in the crimper and do the deed. In the kind I use, a “+” sign is embossed to show you got a good crimp. Some people are happy to stop here, but we are going to solder, too.
To solder, you’ll need your mini torch. A jet lighter will work on these smaller cables, too. Put the flame on the terminal, with the overshoot going away from the insulation.
On an open terminal, like our copper example, poke at the cable to see if it is ready to melt solder. Don’t put the solder in the flame. It will melt and fall into your shoes. On the closed tube terminal, poke the solder in at the gap between the insulation and the metal. When it begins to melt, run it on in. When it begins to puddle you have enough. A slight shake will get rid of excess. Let the cable cool before the next step. Warning: If you are making really big cables like 00 and 4/0 gauge, it WILL get hot.
Shrink tube comes in all sizes and types. There is some really thin cheap stuff on ebay and you should avoid it. The best and most expensive is usually referred to as marine type. It has a melty inner lining that seals up both ends. This is great on boats and around battery acid.
I like to keep red and black tubing to help denote polarity. Sometimes I only have black cable and the colored ends help keep things straight. Ideally, you own a heat gun to shrink the tubing. A hair dryer can work in a pinch. If you are careful, the mini torch works, too. Just back off 3 or 4 inches and keep the flame moving. You can screw it up in an instant.
One other handy trick is to buy CLEAR shrink tube. You type/print a message on paper, like “Main Inverter Cable, Positive”, slip the clear tubing over the cable and slip the message under the tubing. When shrunk, you have a permanent ID for that cable.
So there we have ’em, the new cables to go into the inverter project. I will eventually double up the 2/0 cable going from battery to inverter. The ones that are there are adequate, but I will have less resistance and voltage drop. Why double cable instead of bigger? First, I don’t do 4/0 cable. I can get it for the same price as 2/0, but I just don’t like it. Second, I have the 2/0 cable and maintain a supply of terminals.
In case you are wondering how the inverter project turned out, it went splendidly.
It fired right up without any complaints. I still have a few loose ends on changes to fans and control cables, but it is running and we’ve had no more overloads.
John tells of the glories of swimming with the fish in Miami’s bays. Then he tacks on something solar. It’ll be a while before I get back into the water, but I have some solar sea stories.
I built an electric boat and it was great, but I couldn’t travel with it. I could easily do a 20 mile day trip, but I wanted to go places and explore. That is how Sun King came about.
It was a 16′ Luger Leeward hull stretched to 20′ to give it a more efficient stern. After much experimentation, I installed a single 80lb thrust motor, based on a Minn Kota troller. I outfitted it to do sidescan sonar bottom surveys of our local river. I’m a historian, among other things, and there’s a certain amount of history down there. It is a great boat for exploring rivers.
Did I mention that the electric motor got its power from 6 270 watt “B” panels? So there you go, a solar boat. Infinite range.
The first time I tried my river boat in a bay was nearly the end of me. It sits very low in the water and sometimes bay water does not sit low. Don’t even get me started on the Gulf of Mexico! Eventually I got things sorted and learned to deal with the limitations and I took some trips. Then I got this wild idea.
Have you heard of the Great Loop? Look it up. I know with Sun King’s limitations that trip is a nonstarter. However, there is what I call the Mississippi Loop or the Short Circuit. Essentially, the state of Mississippi, along with bits of Alabama, Tennessee and maybe some others, is an island!
You don’t believe that, do you? An island is, by definition, a parcel of land you can drive a boat around. You can drive one around Mississippi. I’ve done it.
I got in my river and went down to Pensacola, where I turned right and proceeded westward. I turned right again at Mobile and went up the Tombigbee River, which took me on up to Paducah, Kentucky.
The sun didn’t shine every day and on one stretch it went a good 4 days of cloud. I reckon I nailed the balance of solar power (1620 watts), battery capacity (350 ah) and motor load (625 watts at cruise). I did not go fast, but I went steady, often making 50 miles and maxing at 100 miles.
At Paducah, I turned to port (left) and went down the Ohio River to Illinois, where I turned left into the Mississippi. Yeesh. I was not prepared for the next thousand miles, but I survived.
Most boaters doing the Great Loop go south the way I come up. They don’t go down the Mississippi because there are only two places they can buy fuel, at Memphis and Greenville, before they make it to New Orleans. A solar boat doesn’t need fuel. I was doing something with my dinky 20′ solar boat that most boaters cannot do!
So here I am on the outskirts of New Orleans, docked behind the High Tide Bar and Grill and Marina and Convenience Store. I skirted the 12,000 hp pushboats, a hurricane and a tornado, but could I do the Gulf of Mexico? With this boat you want smooth water. Barring that, you want a wind on the stern and the boat will act like a surf board. Weather was lining up to go my way. It was going to be a matter of timing. I sought out local wisdom. I also sought flush toilets and real food. Noodle cups, MREs and Vienna Sausages are sometimes not enough.
I dined on Cajun seafood and monitored a discussion moderated by a young lady on where men could go in New Orleans for certain favors from ladies. She had everyone’s attention until she let slip that the aforementioned ladies were not actual ladies. Her audience pretty much lost interest after that and I looked at her more closely for signs of discrepancies.
I engaged in chitchat for a while with the guy next to me before being introduced to Rain Webb, the artist-in-residence. You didn’t know that a Bar and Grill and Marina and Convenience store had such, but this is New Orleans, mind you. Before he moved on he informed me that I was to meet with him aboard his sailboat later that evening. Oooookay. I don’t believe I have ever had such an evening of discussions on such a broad range of subjects. I really enjoyed it.
The next morning, Rain brought me a sack of avocados and oranges, to improve my diet on the final days of my voyage. He gave me a benediction, of sorts, informing me he was sending angels with me to protect me on my voyage. I thought that a bit odd, but this was New Orleans.
We checked with the cook, a former shrimper, who thought conditions would be good. Rain got in his kayak to guide me on a tour of the nearby fort and then guide me to Lake Catherine, where we parted company.
It was a short trip to the Pearl River, where I holed up waiting for the wind to align. The shrimper I met in a lock had called the waters ahead, “The Chopper.” I didn’t want to get chopped.
Finally, it was time to get underway. The wind was just right for the course I needed to sail, but I had to get around a point and had to tack back and forth to keep the boat dry-ish. Once around the point I was set. The seas were not dangerous, but they were not pleasant, either. After a while I realized that I was going to be out of luck if I wanted a cup of coffee or a hot meal. The galley was forward and I could not let go of the boat for a second. Fortunately, my custom was to rack up bottles of water and tea before getting underway, plus I had MREs behind the seat and Rain’s sack of fruit. I did fine, except for lack of coffee.
In the tedium of it all, it is sometimes difficult to stay alert and on course. I felt the boat bump something, which jarred me alert. I felt the bump a few more times and then was delighted to see I had been joined by a pair of dolphins! I decided they must be the angels Rain had sent with me. I was alert the rest of the way to Biloxi.
The next morning I got underway before daylight, leaving Deer Island around 0500, this time with better provisioning. I made good time to Mobile and owing to changing weather decided to charge ahead across Mobile Bay, which can be treacherous. Believe it or not, my angels were with me again, keeping me alert as night fell and I safely made it to Oyster Bay, a large puddle in the next county. That day I voyaged over 18 hours, dropping anchor after midnight. Solar powered! I know people with power boats that won’t or can’t travel that far in a day. Best of all, there was still enough power in the batteries to run the microwave to make supper that night and breakfast the next morning. I was on the home stretch and it seemed I no longer needed the company of angels. It would be another day and a half before I beached at my home port of Molino and called for the trailer.
And that was the end of forty-four days in the sun. A few years later I had a transporter gig in New Orleans. I took the scenic route home and stopped by the High Tide. The place was abandoned and I was disappointed. I’d like to see Rain again, sometime, and tell him about his angels.
They are now making solar modules with power output in excess of 500 watts! Wow, that’s what I need for the Solar Yacht, instead of the 330s I have now. The thing is, you just can’t buy them, yet. The superest, duperest biggest and bestest go to the solar farms. Don’t worry, by the time the Gopher sets sail they will be available, but you’ll be wanting the 600s.
A few years back, someone came up with the idea of making a “microinverter” and sticking it right on the panel. You plug the panel into the microinverter and a big cable runs along the rows, connecting them to 220v. The solar power mixes with utility power and you get a smaller bill. I thought that was a really lame idea at the time, buying an inverter for each module, but the concept has grown on me. Someone dropped off a case of microinverters and a pallet of 300 watt LG panels, so what the heck? I gave them a try. I don’t have a grid-tie agreement with the power company, so I could not use them as intended. I used them in a most peculiar way and found them to be generally satisfactory, especially since I didn’t have to pay for them. Since I could not put them on my power line at the house, I connected them to the MOTOR side of the compressor relay in my outside a/c unit. Using just enough panels to cover the run current of the compressor, I pretty much got free air conditioning. The biggest aggravation with them is a legal requirement that they don’t kick on until the power has been on for 5 minutes. They are coming back to mind, now. I recall they have a communications bus. I need to see if I can use that for another off the wall idea! Can the communications bus turn the modules on and off or is it just for monitoring? Inquiring minds want to know.
Someone has come out with a new idea for hanging stuff off the back of a solar panel. Now they want to hang a battery! That can’t be much of a battery, but it may not be as crazy as it sounds. It all depends on what they have in mind and I don’t have details on that, yet. It interests me because I am now running my grid tie system, with limiting to prevent inter-tie or back feeding, and I am feeding it with battery. Never mind the advantage of being able to take on nighttime loads, eliminating the variability caused by puffy cumulus clouds, UFOs, Black Helicopters and other troublesome shades you can maintain a steady output from the grid tie inverter (GTI).
I’m holding off on a full article on the subject until I collect a little more usage data, but this one change, adding battery to grid tie, is going to knock off roughly 2/3 of my grid usage, which is already pretty low. The reason it doesn’t get 100% is that I have a clothes dryer that my wife is not afraid to use and it can burn about 3000 watts more than the 1900 watt GTI system can provide.
I am going to keep watch for more of this panel-side battery business. In the meantime, if you go with any of this microinverter or other panel-mounted stuff…mount it on the back side! It’ll work a lot better.
I chased one and it wasn’t what I thought it would be.
A big part of living off grid or keeping the power bill down if you are on grid is efficiency. Try as you may to get everybody in the household to turn off unused lights or to not leave the fridge door open, there can still be waste. Some of this comes from “phantom loads” from devices that still use power, even when they are turned “off.”
Our first TV was a big wood cube of a Magnavox. It had no remote. The switch was on or off. Thank goodness, because all those vacuum tubes used an awful lot of power. Today, my TV has a red light down in the corner and it is glowing when the TV is off. Under the covers, there is a microprocessor that is constantly processing. Oh, the whole off-state consumption is less than just one of the tubes in the Magnavox, but it is power consumption, all the same.
Next to the bed there is a phone charger. It always draws a miniscule amount of power. At the kitchen table, the laptop charger is always drawing. The satellite and wifi gear upstairs is always drawing a lot power. My wife’s rechargeable hand vac stays plugged in long after it is charged. I have a shelf full of tool chargers out in the Solar Shed and they all have a light glowing, even when the batteries are topped. Look around your house and you may find dozens of such phantom loads.
Hey, I’m using free solar power, so what’s the problem? It was a big problem when solar was $10/watt. Not so much, nowadays when John always has super deals on solar power, but come a cloudy day, you can get deeper into your battery, which reduces its life, or you might be on the edge of capacity with your inverter.
It may be it doesn’t matter and it may be that you are just obsessive about efficiency. Handle it your own way.
If you do want to track down these little varmints and are on “lockdown”, now might be the perfect time. There are several tools available to help in your quest but the eyeball is cheap and effective. If it has a glowing LED and it isn’t do anything, “sic’em.” The original portable power meter was the “Kill-a-watt.” You plug it in the wall and plug the suspect into the outlet on the Kill-a-watt. The display tells you how many watts are burning away.
A switched outlet strip is the traditional way of dealing with these offenders. I don’t know about you, but at my house it seems that nearly every outlet in use is behind a piece of furniture. The switched outlet strip moves things into the open. You still may decide to leave that load running if, say, your TV wants to reprogram itself after every power interruption. You don’t want to dash in to view your favorite soap opera, only to have to wait an eternity for the programming to complete.
Another way to determine that you have phantom loads is through the instrumentation of your solar gear. My recent battery upgrade to my grid-tie system let me see what was going on at night. Let’s face it, traditional grid-tie doesn’t work very well at night! What IS this stuff going on all night? Power cycling higher, lower, off, and back on. It almost looks like a fridge, but all of my fridges are on the full-on solar circuits.
I initially blamed my laser printer. That thing is possessed, I swear, and find it best to just leave it unplugged. I unplugged and found the instruments reading zero, so I thought the problem was solved. Then it came back, sometimes burning hundreds of watts.
In the “before times” I might have taken longer to track this down, but since we are “in the now” (I have recently watched all of the Mad Max movies, if you are wondering about the language) I went after it.
This involved pulling the big handle on the breaker panel from the grid. I knew what should go dark and what shouldn’t. Now’s time for “the telling.” The outlet for the aforementioned laptop charger was hot and it should not have been. The laser printer was right there, exonerating it, at least from grid power usage. It still isn’t off the hook for stealing wifi. When I got around to the chest freezer and big fridge, they were silent. Aha, what the heck?
It turns out that when I went to move that circuit from the grid panel to the solar panel box, I pulled the wire from the breaker next to it, giving my laptop solar power, but costing me perhaps 60kwh per month on my grid bill.
Well, adding the battery to the grid-tie is covering that consumption, but it is costing me a bit when I can’t cancel some of the power used by the clothes dryer when it is running. It also cycles my batteries a little deeper at night.
Now the question is, do I have room for another breaker in the solar box? In the “now times” it’s “time for the doing.” We’ll just see.
Sooner or later, you gotta do it, whether it is the clock, the smoke detector in the hall, the car or your solar power system. Oh? You have grid tie and don’t have to change the battery? We’ll talk about that, too.
The batteries that I had on the main bank were in great shape, but there weren’t enough of them, especially now that the brutal air conditioning season has begun. One of the auxiliary banks in my EVs was getting punky. I think I got that desulphated and it is feeling much perkier.
No, the main thing is that I wanted to test a specialty battery before adopting them in the Solar Yacht project. I’m a big fan of GC2/T105 type golf car batteries, like Sun’s inexpensive Sun230 model, but dealing with acid and hydrogen generation in a closed area of the boat was presenting technical issues with which I did not care to deal. The easy way out is to eliminate acid and hydrogen generation.
That left a choice between lithium and some sort of sealed lead acid (SLA or VRLA). The cost of lithiums, if considered over the long term, is a great deal, but it is a bunch up front. This boat only has to last a year, and lithium might outlast me. My government funding budget, which is to say my Social Security check, demands a lower up front cost. John sells sealed batteries at a fraction of what they go for at the Marine store (the one out West) but doesn’t have the size I needed for the boat.
I found some used ones from a guy in Georgia. I don’t normally go for used batteries, but since I was testing durability and on a budget, what the heck? I figured I would get 8 for the main bank, four for the grid tie and one spare. The spare would give me an age-matched replacement should one of the others fail and, in the mean time, provide a robust power source for my 12v Solar Boxcar system. (It is actually a 40′ cargo container, but my wife thinks it looks like a boxcar, so it is The Boxcar.)
I thought to do a reality check. It seems that you can’t actually put 13 of these in the bed of an Avalanche. If you could, you’d break the axle. I settled on 9, which fit nicely and was only a wee bit over gross weight.
It was a nice outing for my brother and me. With Andy navigating, the 514 mile trip became 667miles, but we saw some interesting countryside. Two blocks from our destination there was a minor fender bender. Minor for us, that is. I got a silver smudge on my trailer hitch ball, which tore the fascia off the front of the RAM that rammed us. After acquiring our load, we headed to Talbot County, where I showed bro an old cemetery in the bounds of the old family plantation. He’d not seen it, before. I sprayed 200 year old tombstones with tombstone cleaner and he learned a little genealogy.
On the way to another family plot in Harris County, we passed a new solar farm under construction. It looked like progress may have been halted by virus worries. There were some neat, shiny rows and there were some torn up acres still piled with stumps, but no activity. After cleaning up some more great-great grandparents’ rocks we limped back to Florida, as a tire had gone bad somewhere along the way.
Then the fun began. Saturday, between old coming out and new going in, I moved over a ton of batteries. Literally. Another 500 lbs would wander over to the grid tie project on Sunday afternoon.
I was in luck. I had most of the cables I needed, already. Nice fat 00 cables with marine shrink tube on the terminals. I had to make one cable to join banks, but had the wire and connectors. When you buy supplies like this, always buy a few extra. If I hadn’t had these, then I would have been delayed for a week or two, waiting for them to come in the mail.
Overall, I only had to switch the house to the grid for a few hours and everything came back online without a hitch. It really pays to check everything twice, from voltage to polarity.
OK, listen up! This is where we get to the educational stuff.
The main bank is two strings of sealed VRLA batteries and the two auxiliary EV banks, when they aren’t elsewhere, are flooded lead acid (FLA). THEY HAVE DIFFERENT CHARGING CHARACTERISTICS. Time to reset the charge controllers.
Let’s go back in time a bit and I will tell you why I have been hesitant about sealed batteries. Tom, my nearest solar neighbor to the west (12 miles by air, 20 by road) bought 3 strings of the nice Outback VRLA batteries. He connected them to a 10kw array and fried them within two years. There was way too much charging current. There IS a specification for that. After some experimentation, I was able to bring most of them back. One gave its life to science. OK? So, you see that I am not wanting to kill my new batteries.
Reading the fine print (always RTFM*) I learned that you should not exceed 40 amps charge rate per string on these new batteries, should float them at 54.4 volts per string and you can bulk charge for a while at a higher voltage. Now the fun begins because I have 4 charge controllers, three different models and I haven’t been into the menus of two of them in quite a while. I set the twins at 54.4 and 54.3. I offset them a little so they don’t just drop out at the same time. Another controller had a menu selection for VRLA battery, but it has only one button and you have to combine short and long pressings to get where you want to go with it. Mo’ buttons = mo’ better, I have decided. Then there is the FM60. It is wonderfully adjustable, but there is a password and there is a trick to getting into hidden menus. Hint: shut it all down, press and hold the correct TWO buttons and turn on the breaker to the battery. There’s a whole new world of menus in that thing! Save yourself some grief…RTFM.
Next morning, I kept a close watch on charge rates and float voltages. All was well. Nailed it!
What about the EVs? They will be perfectly happy with the VRLA settings, but they won’t get into the equalization stage. They will have to be taken offline every now and then for equalization, which is basically a quick overcharge. DO NOT equalize sealed batteries! They burp out the gases, which cannot recombine to replenish the electrolyte. They dry up and die a horrible death. You mourn their death when you have to buy more. Don’t kill your batteries.
Now, as for the Sun230 batteries that I moved to the grid tie system, I think I will save that story for later. If interested, do your homework and look back through the blog for the GTIL or grid tie limiter stories. But yeah, we’re gonna put batteries on Grid Tie.
Spare, extra or redundant, call it what you like, chances are you are going to need more. Oh, yeah, there’re fuses and connectors and such as that, but I’m talking about wire and cable, here.
When I was a young broadcast engineer at WCOA, Pensacola, I engaged in a total rework of its broadcasting facility. It was tricky, since the station had to stay functional while the new stuff was being installed. An important part of the installation was the rewiring.
At one time I could have told you exactly how much wire I pulled. I can’t now, but I can tell you it could be measured in miles. I handled so much wire that my forearms broke out in a rash from the PVC oil in the insulation. Lots of wire went everywhere there was a studio, including lots of spare wire. Every room had a junction box and active cables went to rack mounted patch bays. In addition to the normal arrangement, any studio could be patched into any other studio, for whatever purpose.
Well, plan as you may, you can’t think of everything, so we ran lots of extra wire in every direction. Sure enough, those extras started getting used. Amazingly, all the extras from Studio A to the AM control room soon got used. No problem! We’d just route through another room.
That kind of thinking stuck with me into my computer career. Every room in our new headquarters had cables going to a patch bay in the computer room and, sure enough, it wasn’t long before things started getting routed all over. Then came that new-fangled arcnet and ethernet stuff. We hadn’t even conceived of that when we built the place, but had left available access and pretty soon every room had both.
The same sort of thinking ahead can pay off in designing your solar power system, too. My Solar Shed is 200′ from the house, so it is a major pain to run a new line, especially considering there’s a water line in close proximity. In addition to the main power line, there is a conduit containing 5 cables, which are now in use, and a spare, empty conduit.
My limiting grid tie experiment is progressing and because of the versatility of the extra cables, I have been ok, so far. I am considering that empty conduit, but pulling stiff wire through 200′ of conduit is easier said than done. I actually have some 10″ and 12″ concrete pipe that would have made a wonderful conduit, had I thought about it. Boy, could I get some wire through that!
For an ordinary installation, you probably don’t need huge conduit, but consider putting in some extra cables and empty conduit. Sure, it is an extra expense if you never need it, but getting a trencher or backhoe to install new work without cutting up the old stuff can be expensive and even perilous.
OK, so your modules aren’t 200′ away, they’re on the roof. It will be pretty easy and cheap to install a combiner box that is a little bigger than your minimum requirement and to put a few extra runs of solar wire. Maybe even put in some small control or sensor cable in case something comes up where you want to monitor temperature or something else up there.
Leave access, too. My solar control room is also now my Man Cave. The ceiling and walls are all closed in where you can’t see the wires. There is yet another expansion of the Solar Shed planned, which may add 50 to 150 more modules. That means lots more wire, but it isn’t a problem. Wall panels around the control panel were installed with screws, so it will be easy to get the new wires run. The wall effectively becomes a raceway and raceway is much easier than conduits for channeling big bundles of wire.
The point of all this is to say, “think ahead” and make it easier on yourself in case you can’t think of everything.
I wrote the material below quite a while back and it somehow fell through the cracks. I have since gone through a couple of variants of a Zero Export Grid Tie system, including a new one this past weekend…and the power company’s meter hasn’t budged since! Read this to get up to speed and there will be more on the latest changes.
The season is changing and so are the solar connections at the Solar Shed.
Grid Tie can be the cheapest way to get into solar and can even turn a profit for you in some places. In other places, the system is rigged.
A much cheaper way to do Grid Tie is a Zero Export Grid Tie (ZEGT) system, using solar power mixed with grid power to run your loads, but not to back feed into the grid. I call this “house tie solar.”
Why is this even a “thing”? Why not just grid tie, using the grid as a virtual battery? Straight grid tie with net metering is a great deal where you can get it. Daryl, in Texas, has a great deal on grid tie and his huge system actually makes him an income stream. A lot of places you can’t get it, though. A lot of places where you could get it have changed the deal. Bruce, in Pennsylvania, ran into this. He’s the one who reminded me of ZEGT.
Let’s say you live in Alabama. I think a recent article said they have $50/month tie fee and it is going up! Here in Scenic West Bogia Heights, Florida, that’s sort of the same sort of deal, but ours is higher if you can even work it out. You pay for a bunch of extra metering equipment and an electrician to install it. Your solar system has to be signed off by a certified tech. Then, on a monthly basis you have your basic $40 connection fee and a $60 solar fee. That a hundred bucks of power bill before anybody gets any power.
Turn on the juice and all the power that you make and don’t use at the time goes to the power company for less than 4 cents. At night, you get to buy your own power back for 13 cents. I am no math genius, but I think under these conditions it will cost you more to have solar power than to go without. Maybe we should run some numbers on this.
Let’s say you use 1500kwh per month. You build a grid tie power system that can supply 1500kwh per month. At 13 cents that’s $195 from the power company. Now let’s figure that the a/c and fridge and the miscellaneous loads (like the clock you can’t set on the DVD player) will use 500kwh in real time, reducing the intake from the power company to 1000kwh, which at 13 cents is $130. 1000kwh of your excess daytime power went to the grid at 4 cents per kwh. You get a credit of $40 off the $130 net grid import, so you have to pay $90 for your power. You also have to pay another $100 for the meter and solar fees. That makes your bill $190 with your grid tie connection. Without it, your bill would have been $195 plus the $40 meter fee, or $235. Ok, so you did save $45. Did I mention that West Bogia Power and Light also requires that you buy a multimillion dollar insurance policy to indemnify them should your dinky little power system damage their grid! The average squirrel can cause more damage to their system than a proper grid tie system can! Hold on, now, I have a solution or two for you.
First of all, and this costs little or nothing, change your ways. If you use more of that solar power before it leaves the house, then they don’t pay you 4 cents and charge you 13 on the power that goes out and comes back. If somebody is home during the day, do the laundry and baking then, instead of in the evening. Set the thermostat for more run time during the day instead of at night. If no one is home during the day, is someone close enough to come home and start the dryer? If nobody can make it home during the day, start a crockpot meal before you leave for work and set a water heater timer to heat during the day. Look into smart appliances that can be controlled with a phone app while you are away!
Having shifted your loads a bit, you are now burning 1000kwh of solar and 500kwh from the grid. You are also selling 500kwh to the grid. That comes to 500 x 13cents to buy, 500 x 4 cents to sell for credit or $65-20= $45. Now add in the various fees and the bill comes in at $145.
Let’s review. Your bill without solar would be $230. Your bill with the first grid tie example would be $195. Changing the routine a bit the bill with solar is $145. OK, I think we are getting somewhere. What else can we do?
The availability of ZEGT can help get new prospects into solar and can help get folks who have had the rules changed on them get back into a profitable state.
Let’s go back to our example, only now no power is backfed to the grid. We CAN make 1500kwh, but we still only use 1000kwh during daylight hours. We discard the excess capacity because we are not exporting to the grid.
As with the previous example, we are importing only 500kwh from the grid. Again, that’s $65 for power, no credit for exported power, $40 for the meter fee and NO SOLAR CONNECTION FEE. That makes the bill $105!
Let’s try that in the example before changing our ways with power consumption. I believe we were using 500kwh of solar, dropping what we buy from 1500 to 1000kwh. That’s $130 for the power you buy, plus the $40 meter fee, for a total of $170 as opposed to the $195 you were billed when the power company was “buying” your excess power!
As usual, your mileage may vary. Your power company may charge more or less, pay more or less and have different requirements and fee structures. Zero Export may or may not be for you. A lot of you have banged on the calculator and are now wondering what it is going to take to build your new ZEGT system or convert your existing GT system.
If you have an existing GT system, RTFM. That’s right, read the fine manual for your GT inverter. Many, especially those made in the last few years, have this capability built in if you add a device to monitor the power line and report back to the inverter. These go by various names, often coming in the form of a power meter or electricity meter, originally intended to just let you monitor your system. Two current transformers slip over the grid lines coming into your breaker box. They connect to the “meter”. The meter has an RS485 (or other communications standard) that connects with the GT inverter. A few changes are selected from the inverter’s menu and now the inverter knows when the solar power need to get in and out of the mix to match the consumption, when possible, but not overdo things and send power out. Hence, you can tell your power company to pull the extra meter and discontinue grid tie.
If you do not find anything on export limiting in your manual, check out a company called ELGRIS. They have an export limiter that they claim works on a lot of GTI models and may have one for yours.
Now for new solar users, hold on. There are reputedly some inexpensive modules that will do the trick and installation is pretty easy. I say reputedly because I have not personally tried it, but I have heard good things. I have ordered two units and will quickly get them installed on my minigrid for testing the ZE claims. If that goes well, then I’ll go live with them and report results, like whether or not the power company busts me for backfeeding. Tom got a visit from the power company within 2 hours of inadvertently backfeeding his system, so going up against West Bogia Power and Light with these new gizmos is a really good test.
We have some new buzzwords in our vocabulary and a new normal. Self-isolating and social distancing.
Miami is kind of a hotspot in Florida, so John has the store closed so everyone can stay safe. Roberto is manning the phone, though, so if you need something you can still get it. The phone transfer mechanism leaves a bit to be desired as far as sound quality goes, but I had a chat with Roberto and if you need to deal, you can get it done.
I also had a chat with John. He is hunkered in place in his concrete bunker, I mean condo, there in Ivory Towers, overlooking the idyllic land of flamingos. I think he is going stir crazy, wanting to go to the jetty and commune with the manatees, but with John it is hard to tell. You’d think he’d write some new blogs! Get with it John! He anticipated me, so check out his latest rantings.
A natural question is “what are you doing”? A lot of people are comparing notes. Well, I am doing pretty much what I always do. On a farm there is about twice as much that needs doing as there is time or, in my case, inclination to do it. Self-isolation is pretty much my normal state. My wife goes out and collects the germs and brings them back so I don’t have to.
I do go to town every week to donate platelets. Blood banks are in low supply due to cancelled blood drives. I figure I am safe enough there, with everybody wearing gowns and gloves and swabbing everything with alcohol. Safe, that is, unless Eman is there. Treat her right or she can and will hurt you. You might consider a trip to your blood bank. Don’t worry, Eman only works in Pensacola.
Now, since this is a solar blog, why don’t I point out some solar-y things you can do while you are at home?
Spring has definitely sprung. The pollen has coated the panels and the berries are making fruit. We usually have a late freeze in March, but not this time. And no rain. What that means is the thick yellow pine pollen, mixed with a little dew has caked on the modules and is reducing the output a bit. Well, we can’t have that. I took a broom after the lower panels in the experimental banks, but it did little good. I am hoping for an afternoon shower to wet them so I can get after them with a long-handled scrubber tool. Otherwise I will have to drag enough hoses out to use tap water.
I had a feed pipe to my water-powered pump come loose, so my water pressure is slowly coming back after repairs. It was an easy fix, but there was a large water moccasin guarding the pipe. That kept me looking over my shoulder. You can shoot a snake and he will slither off before he dies, or you can miss him and he will slither off and make plans to get even. Sometimes you aren’t sure of how it went, so you just stay wary. Water mocs can be mean and aggressive.
I suppose I could also work on my solar water pump, Version 3. The first two were nice, except the submersible pumps quickly died when submerged. Hardly seems right. Just need some fittings and a round tuit to do that. A simple rack of treated lumber has served to hold the panels, recycled 34 watt solar shingles. A lot of times, you don’t even need a charge controller and a battery for a solar pump. Version 3 will have a pump that does not live underwater. I have learned that lesson.
If you have solar, there are the mundane chores you can tend to. Water the batteries, tighten battery terminals. Equalize the batteries. Change the oil in the backup generator and give it a test run. Tighten connections on your charge controllers. Check your instruments to see that everything is really working. Take a look at those MC3/MC4/Tyco connectors to make sure they are tight.
Oh, and if you can see the back side of your panels give them a look. It seems that in the big solar rush of 2010-2012 some substitute materials were used for backsheets and they can break down, leading to eventual failure. How old are your panels?
Some time I will do a piece on repairing modules. Even if you don’t have a backsheet issue, you should check for hotspots. I had a panel with a hot cell that discolored and cracked a 6 inch square area on the backsheet. If you find one of those, take it out of service until you can repair the problem or replace the module. I think I had a bad diode cause my hotspot, but shading and leaves can cause a problem. That’s another reason I need to keep the pollen off, because a lot of the modules in the experimental rack are not even mine. When I get to it, maybe some time I will do a piece on repairing modules. You may have seen the article I did on how to destroy them.
How about a new solar project or upgrade? I finally found some specialty batteries I can use in the next phase of my Grid Tie Limiter project. So I will dash out this week to fetch them, wishing I had a bigger truck to carry more. More on that, soon.
Finally, I did a little fun project with old solar panels, dead ones. Out at the Solar Shed, rain has been getting on the door to the Man Cave. It is cypress and it shouldn’t matter, but it swells up a bit and makes it hard to work. I took a couple of “inert” solar shingles and fashioned an awning. It was easy and it looks great. Eventually I will use them to build a carport for the farm EVs, but this was just a quick job. While I was at it, I added a couple of pecky cypress planks to serve as trim.
So, what kinds of solar chores and innovations are you doing while holed up? Peruse the Sun Electronics website for inspiration. If you want a good chuckle, compare John’s prices to other websites. I guess they can fool some of the people some of the time!
The homes of my grandparents were special places when I was a kid. Bro and I went by the former Collier house on a recent trip to Lake City, Florida. It was a sad sight.
The big camphor tree, where Dad had his tree house is now just a stump. The yard is grown up. The house looks shabby and gutted. The old houses of Lake City had a great architectural element in their pressed tin roofs. You never had to replace them if you just sent somebody up every 10 years with a bucket of silver paint. The roof has been replaced with asphalt shingles. I guess the more recent owners didn’t get the memo about the silver paint.
The house was built sometime in the 19th century, but I don’t know when. I know Lake City was around during the Late Unpleasantness because the residents got even with Yankee soldiers by throwing their rifles in the lake across from the boarding house while the blue coats were having lunch. True story. A few years back they drained the lake and found the guns!
Does Grandmother’s house date back to then? Dunno.
When the house was built, it had indoor plumbing, consisting of a pitcher pump at the kitchen sink. When city water and sewer came along, a bedroom was converted to a bathroom and later another bedroom was added.
Electric lights, a fridge and an electric range replaced the lamps and the icebox and the kerosene stove gave way to an electric range. The kerosene stove used a large glass jar as a fuel tank. Yikes! Central heat started out as an oil burner and later a gas furnace in the dining room, the center of the house. By the late 60s there was a window a/c in the dining room, as well.
We get a taste of something new and better and we want more of that new and better stuff. Human nature.
They discovered the same thing at the DelcoLight company in the 1920s-30s when light plant salesmen fanned out across the country side. They’d show up around sundown in a Model A Ford with a light plant stuffed in where the rumble seat would normally be. They’d give a little pitch about how better light would make it easier for the kids to study.
Yeah, they’d go to the Moms and save the kids. Worked every time. Once they had a foot in the door, they’d go on about all the other wondrous things you could do with electricity. Save time and labor on pumping water. Fresh water would make the cows give more milk. Oh, and you could have an electric cooler to preserve the milk. Oh, the wonders of electricity!
Then the guy would go out to the Ford and drag out a long cord with a light bulb. He’d put that in the parlor and turn the switch. Behold! Let there be light! The electric bulb, dim by today’s standards, outshone the oil lamp and clinched the deal. It would not be long before the house was wired for more than just a single lightbulb hanging on a cord from the ceiling. We always want more.
As I have grown my solar power system I have added more and the bill from the power co-op keeps getting smaller. We are now up to 3 refrigerators and a chest freezer. I’m charging 2 EVs and a boat, which in turn share their batteries. The two central a/c units are on solar. Welding and woodworking are solar powered, as are the chainsaw and other commonly used tools. The Man Cave has a rudimentary home theater and is getting a/c.
More, more, more. My inverter is getting toward its limits, as is the battery stack. Well, I can always stack more batteries and I have a bigger power module I can stick in the inverter cabinet when the time comes.
The moral of these ramblings is “Plan for Expansion.” If off grid or hybrid, get the biggest battery pile you can afford and not one of those dinky, toy Powerwall thingies. Get an inverter that can be run parallel with another so you can double up, later. If gridtie, you can add more solar strings and inverters to cover the bill.
Did you ever read, “A Tree Grows in Brooklyn?” I can’t remember if I ever did, but I know I had the book. If there is a tree there, I’m sure the dogs appreciate it. There probably isn’t much solar power on the neighborhood level in Brooklyn, so all is good.
There are lots of trees at my place. It is a tree farm, after all. The blooming Paulownia grove is a delight to the senses, right now. The pines, the ones the beetles aren’t eating, are clogging my lungs with pollen. The green pickup and the blue solar panels are yellow with the pollen. Then there are those danged oaks I have killed every year for the last 3 years. THEY are putting out again, indicating maybe I didn’t do such a good job of killing them.
I have talked about these before, but I feel like venting again.
Why am I trying to kill them? One is to the north of my array and the canopy does not hang over the panels, but the arc of the sun is such that it gives a bit of shading on a couple of banks, midsummer, when I need all I can get for air conditioning. I’m adding MORE a/c in the form of a mini-split for the Solar Shed’s control room/Man Cave. It hit 95 out there yesterday when I was working on taxes. That’s starting to get too warm.
The other big oak is off to the east and causes a slow start to the power production in the morning. The original phase of the Solar Shed was only 16′ long and was not affected, but the shed has grown and is getting near the canopy.
Dad used to kill the oaks in the planted pines two ways. They had a backpack-mounted machine called a Little Beaver. It would gnaw the bark away around the tree. This is called girdling and it interrupts the flow of nutrients.
They also had a thing that looked like a bazooka. You’d bang a pointy beak into the bark and pull a trigger. That dribbled in a dose of Agent Orange, as they called it in Southeast Asia. Agent Orange is the good stuff, but Home Depot doesn’t carry it, for some reason.
Well, I started with girdling, using the solar chainsaw. I have girdled a second channel. I have attacked the trees with a flamethrower. I have axed away all the bark between the two channels and charred the raw wood. I have bored holes in the trunk and roots, filling repeatedly with herbicide. And a different herbicide. And copper sulphate. The trees are filling out beautifully with the new leaves.
So why not just cut them down? Listen up. I was a Boy Scout, a half century ago before they ruined Scouting. I have skills. You put a bottle cap within range and I can drop a tree right on it. The rules for tree felling do not apply, though, when near expensive stuff and they totally go awry if there is a video camera running.
Therefore, I have turned to just plain killing in place. When you can actually get the tree to die, the smaller limbs fall straight down and the larger limbs come in pieces. You end up with the central trunk, which is easy to handle.
My next step will be to pour rock salt around the tree bases and to call my crop duster friend Rex. He has a reputation for killing every living thing in two counties whenever he goes up with a load of Roundup. He also managed to kill a 50′ swath of trees with an emergency dump of fertilizer at my place, last year. The man is death on wings.
If there is any point to this rambling, it would to be to advise you to take care of the tree issue before you start putting up panels.
It has been in the 80s here for a week. When the nights were still dipping down low enough at night the house would stay cool enough. Not now. It is time to fire up the a/c. The solar-powered a/c.
I have written about combining solar and a/c before. Go back in the blogs to find the articles. I’ll update some things, here.
The house started getting undeniably warm, so it was time to get the a/c going. Normally that would just be the flip of the switch, but I tend to mess with stuff. Last autumn I was rigging the heat pump (downstairs unit) to run on solar when I bumped something or knocked something loose. The heat pump would not pump heat.
Well, no worries, I have not used it in years, anyway. Not for heat, at least. I have an outdoor wood furnace that runs on beetle-y trees I need to cut down anyway. It is super efficient and costs practically nothing to run if you have an unlimited supply of wood and a solar chainsaw. The current generation of 40v and 80v rechargeable saws is great! So I just forgot all about the heat pump, having other things to do.
My first attempt at firing up the a/c (upstairs unit) yielded nothing. The downstairs unit was missing the lockout relay, so nothing was working. I replaced it and life is cool.
If you are planning a house, consider inverter or variable speed units. If the layout is simple, consider mini-splits. Here is why.
These things are super efficient. My rattly old units were “hi-efficiency” at SEER 13 when new. These inverter units run 18-25 SEER. That means a low power consumption even if you don’t have solar. If you do have solar, there are more benefits in not having to have as many solar modules, batteries, charge controllers. You don’t need as big an inverter. A friend and I remodeled a carriage house in Georgia, replacing two loud, inefficient SEER8 window units with a 2-head mini-split. It is awesome! It doesn’t start and stop. It speeds up and slows down. You don’t even know it is running most of the time.
A conventional a/c compressor starts up with a tremendous power surge. My sturdy 5kw inverter would not start either of my conventional units. An inverter a/c eases its way into operation and the inverter barely knows anything is going on.
Wait a minute. Time for definitions. My 5kw inverter is the big box that turns the solar DC volts into household AC volts. The inverter in the a/c is a variable speed controller. Got that?
You either make it easy on your solar equipment or you buy more of it. Maybe better to spend a little more on the a/c than a lot more on everything else.
Here is a curious thing. A/C guys don’t seem to like variable speed split units, though the mini-splits seem to be catching on. There is more potential for something to go wrong and I think most of the techs are simply not comfortable working on them, yet.
In the meantime, if you have a legacy system, there are things you can do. Add a Smart Start device. It connects to the contactor and condenser in the outside unit, allowing the compressor to start up over 2-3 seconds instead of instantly. My 5 kw inverter does not even grunt and it settles down to a 2kw load to run the a/c.
Normally the upstairs unit, set to 71 will keep the downstairs at the target 75 degrees with no problem. Last summer, when temps frequently hit over 100 degrees, it needed a little help. I did not think it a good idea to run BOTH units at the same time, especially since the inverter was in a room that typically ran 135 degrees during the day. A LOCKOUT RELAY was installed in the downstairs outside unit. This is a simple 24v single pole double throw relay that activates when the thermostat operates that unit. When the relay clicks, it interupts the thermostat line to the upstairs unit.
Use programmable thermostats! Oh yeah, that was something else that hindered my startup. The thermostat needed a new battery. Anyway, the programmable thermostats let me set the house much cooler during the day when the free power is shining and then back off at night to save the batteries. Yes, we did have to run some at night when the temps never dropped below 80 after being 105 during the day.
Downstairs gets a boost from its larger unit, but only when needed and I don’t have to upgrade my inverter. Of course, I still need to fix the downstairs unit that I broke. Always something.
My brother and I drove across Florida from Pensacola to Lake City on business. It was good to put faces to the voices we knew from the phone calls. What we were not expecting to see were thousands of solar panels. The last few times I’ve been across Interstate 10, all you’d see of note on I-10 was the devastation of Hurricane Michael.
Suddenly, I realized something and told Andy, “Hey, we own that!” At least we own a few hundred shares of the company that owns that.
That Florida, the alleged Sunshine State, has solar farms is not unexpected. Suwanee County is timber country and was not devastated by the hurricane. They did have some pine beetle problems, so maybe they decided to get out of the pine tree business and into power.
I found some newspaper clippings and was surprised to see how quickly it had happened. NextEra started the approval process something like a year and a half ago for a solar farm that is to be built a mile from my place. There was a flurry of activity last year with surveyors and such, but not the first post hole has been dug. You just wouldn’t believe the regulatory hurdles involved!
Financing is always an issue and so is material supply. So many solar farms are going in that the module plants are running flat out with backorders. Folks who use import panels are now having to deal with China essentially being shut down owing to the Wuhan Flu. It is always something isn’t it?
On the return trip, as we drove west of Tallahassee, approaching Marianna, we were back in the hurricane zone. Millions of pine trees were broken off half way up. Acres of land were layered as high as a house in wood chips made from clearing all the downed trees. This seemed an area suited for a new solar farm. The entire power grid was wiped out in this area, so they had to start from scratch. Have they incorporated Solar-Plus-Storage in their plans? Don’t know, but it would seem a good idea.
More notable than the solar farm we saw and the place I thought would be good for another one was the total absence of rooftop and backyard solar. Maybe we just didn’t see it from the Interstate. Again, if you are rebuilding from scratch and had gone through a period of months without power, you’d want solar, wouldn’t you? Perhaps the priority was to get a roof and solar will come later.
If you do decide to go solar, YOU should not have to worry about the kinds of shortages that concern the big boys. John does not generally import the Chinese modules and much of what he buys comes from factory closeouts, bankruptcy auctions and used panels from decommissioned arrays. You’d be surprised how much of that stuff is around when you have a solar bloodhound like John on the hunt. Sun Electronics always seems to have a good inventory at great prices.
I don’t watch much TV, beyond the network evening news. I was in the kitchen eating when my ears perked up about something solar on 60 Minutes. Then I heard Rocky Mountain Institute mentioned. I had to watch.
You’ll recall that a Cat 5 hurricane clobbered the Bahamas and just smashed the Dickens out of parts of it. Traditionally, power in the Bahamas comes from a Diesel plant on every island. Fuel deliveries are ever a logistical challenge. I’ve not personally seen that in the Bahamas, but I did see it in the Caymans when I was a computer tech back in the last century. The power made by the Diesel plant was fairly dependable, but not really “clean” the way computers like it…hence my island visit.
60 Minutes didn’t talk much about the Diesel generator, except that it was over yonder and most of the users were here, 20 miles away. Not a power pole was left standing in between. I am betting the big engines ran just fine. The problem was how to get power from yonder to here. It would require new poles and lines, like folks didn’t have enough other stuff to worry about.
Then somebody came up with the idea of microgrids. Put the power source close to the users! You can still tie microgrids together to make a big grid, too. The plan is to put a few acres of solar here and a few more over there until everybody has some.
Enter the guys from Rocky Mountain Institute. Google them when you finish here and download some papers I am going to tell you about.
You say they are going to put up solar panels. Didn’t nearly every house on the island just get flattened? How are solar panels going to stand up to 180 mph winds?
That’s where the Rocky Mountain Institute boys come in. A while back, they studied solar panel failures after storms. For the most part, the failures were either caused by flying objects or the panels themselves became the flying objects, causing more havoc. They concluded that it would be a good idea to mount your panels well enough that they stay put and do not become flying objects. They are taking it a step further on the island system, mounting them very low and skirting the to keep the wind from getting under and lifting them.
Duh. Well that may seem obvious, but nobody had really analyzed installations and failures to see what that meant. Turns out it isn’t that complicated to tie things down and a lot of common practices need to be changed.
You can find the Rocky Mountain Institute website and download the free pdf report for all the details, but I’ll hit the highlights. Oh, I should warn you…there will be graphic photos of smashed and twisted solar panels. It’ll break your heart.
So many times you see one clamp between the edges of two panels and a bolt going down between them to the frame. Don’t do that! Use separate clamps for each module.
Don’t hold things down with screws. Use bolts.
Make sure your supports are firmly in the ground.
That’s just hitting the highlights, but it makes sense. It really doesn’t take much to hold the panels down under normal conditions. When the hurricane comes, the challenge is simple, though: keep the panels in place.
To avoid wasting land for mounting solar panels, a lot of microgrids try to use rooftops. Keeping a rooftop in place can be a challenge and a necessary part of installing solar. Many of the same techniques apply to rooftop solar, but the challenge has to include keeping the roof in place. Keep the roof in place and chances are you can still use the building after the storm! RMI just finished a paper on rooftop system survival, so be sure to download that one, too.
To emphasize their point as to the value of microgrids, they used Puerto Rico as an example. After the total destruction of their grid, solar microgrids were installed at schools. The recent earthquakes knocked the grid down, again, but the schools and other buildings so equipped had power. Hurray for solar!
Another point made in the story was that building a solar power plant is now pretty much on par with building any other source. Batteries have come way down in the last few years, though we individual users would surely like to see some more breakthroughs.
I look at my own system and really, really hope we don’t get a hurricane. We are overdue, here, near Pensacola. My recycled solar shingles are only rated at 60 mph. That’s just tropical storm level. There was an optional clip that is no longer available, but I could replicate it, sort of. The problem is there are hundreds of panels and not all of them are readily accessible.
Most of my conventional panels are on temporary mounts for some of the cockeyed tests I am running. I know they could be better and they could be easily bolstered or just taken down in a few hours. The entire mounting structure is wood. Wood has some give in a stressful situation, but it is all very high and there are no bolts. The framework was put together with a nailgun to get started and long deck screws were added to strengthen the bond. Metal straps would be better and maybe they will get added.
After reading the RMI reports, I am a bit nervous about my own installation. Upgrades are not out of the question, but it is quite obvious that it would have been a whole lot easier to put them in place during construction and they really would not have cost a lot extra.
How would you rate the survivability of your system?
Kris Kristofferson had a big hit with a song on that theme. Instead of moaning about why things had gone so wrong, though, he was wondering why good things had happened when he felt he didn’t deserve them.
Well, things can go wrong in your solar power system, just like anything else, and you’ll have to get off your wallet to fix them. You can ask, “Why me?”, but if you are just feeling sorry for yourself it’ll likely happen again. If you ask “Why me?” constructively, that is to say, analyze what you might have done differently, you might end up with a better and stronger system that won’t have such a failure in the future.
Here at the Solar Shed, I have all kinds of experiments running. Many are temporary, but sometimes stick around longer than expected. If I get sloppy on these temporary rigs, then it can get expensive. Also, different circumstances seem to offer different “learning experiences”.
Example 1–Do you know what the schematic symbol is for an antenna? Visualize an upside down wire coat hanger and you have a pretty good idea. If you have 3 solar modules in series, you can twist all the wires together and have the pair for the downline together or you can have them take the shortest path, with ends up with a more or less triangular circuit…just like the antenna symbol. Now, a loop antenna is directional, so if lightning hits the tree over yonder, the induced current from the blast may be out of phase and not bother your system a bit. OR it may be 90 degrees around and channel the hit right into your system, which can get expensive. Trust me, I know this to be true. Keep your wiring tight and not looped.
Example 2–If you do not have a surge arrestor on your system, you should not complain about a surge getting in and causing havoc. In the spring time, we have some really nasty lightning storms around here. I mean, go hide under-the-bed-with-the-cat-bad storms. In a case of Example One and Example Two combined, you may discover interesting things. For one, a charge controller might NOT be injured by lightning, but because it operates slowly it can pass it along to your inverter. The inverter monitors its output and adjusts according to the input with which it has to work, but this adjustment is not lightning fast, so you can get some really interesting effects. One brand of inverter I had online would blow its display board. It was the weakest link and it took the hit, saving everything else. It would run just fine without the board, but I had spares. After a couple of times of this, I was out of spares and decided to run without display. I had other meters. I did, however, lash up an output surge arrestor. Good thing. The next storm did not kill the inverter, but it wiped out the feedback loop, so it got the urge to keep making lots of voltage…lots more than is considered socially acceptable. Fortunately, I had put in that output surge arrestor and only it went up in smoke. Otherwise, everything in the house on that circuit would have been destroyed. The saddest part of the story is that my new 48v system, not yet online, lost its big 12kw inverter. Have you priced a 12kw inverter? They cost a lot more than surge arrestors! I think the system packages that Sun Electronics sells pretty much have arrestors in the kit, but ask. If building a system a la carte, install surge arrestors!
Example 3–Nothing bad happened, here, because I was prepared. Lots of gear has fans in it. All of my charge controllers have them and the Sun King 5548 inverter that I built in the shell of my deceased 12kw inverter recently had one of its fans start getting noisy. There is a manual fan in the top of the case that I use a lot in hot weather and another fan operated by a thermostat on the transformer. That one never runs as I am running 5500 watts on a 12,000 watt transformer. Right down on the driver board, there is a small fan that runs based on the heatsink temperature. This one is pretty important and it would rumble and howl when it started up. In this inverter’s design, heat won’t cause it to blow up, but it will shut down until it is comfy again. Having the lights and a/c blinking on and off on a warm day is really annoying. Folks, when your fans start talking you need to listen. I have a drawer full of fans for just such occasions. I bought two extra when I built the inverter and I have several more dissected from old PC power supplies by an 11 year old who likes to take things apart. Never throw away working fans! If you buy replacement fans, TRY to get ball bearing fans. They cost more than fans with sleeve bushings, but they last WAY longer. The specs, like voltage, current and airflow (CFM) are usually printed on the hub of the old fan. Listen to your fans. They mean it!
Example 4— Pay attention to the meters. I recently pulled a set of 2 year old batteries from the system. Why me? I have batteries 5 years old that are just fine! Interestingly, it wasn’t just one battery with a bad cell. I was hoping to use some of that set in other 12 and 24v systems around the farm, but No-o-o-o-o, they were all bad. Curious. Well, it seems I had two charge controllers that had a bad firmware revision and may have had some damage from all those lightning episodes. Since they run less than half the power for the whole system and otherwise seem well-behaved, I ignored the high-ish afternoon voltages, thinking they were supposed to go that high as part of their multistage charging act. Nope, they were cooking the batteries. Pay attention to the meters. They are there to tell you stuff!
Example 5–Unless you have sealed batteries or some of those fancy Lithium packs, then there’s a good chance you will need to add water to your batteries from time to time. How often depends on how hard and how deep they are cycled. If you pretty much use up the battery at night and have enough solar to charge it hard, you will probably go through a good bit of water. Once a month is probably good for most folks, but that previously mentioned set that died young was going through gallons every two weeks. Keep the water above the plates and use only distilled water. It is only a buck at the grocery store or WalMart.
Example 6–Keep your terminals tight and clean. Terminals just get loose and need to be tightened. Otherwise, they can run hot and waste power or even burn off the lugs of your battery or inverter. Just today, I opened the cover of a charge controller to get to the temperature sensor wire and while I was in there I decided to check the terminals. Two were not loose enough to cause harm, yet, but needed to be snugged up, just the same. On your batteries, you can add the threat of acid corrosion. Don’t let that green stuff build up. Clean it up and coat with grease for protection.
Example 7–Pay attention to the heat. I haven’t had any problem from this, but it got uncomfortable in the Solar Shed’s control room/man cave last summer. There was no ceiling, then, and the backside of a solar panel is hot. The IR thermometer showed 140-150 degrees and the room was routinely over 110, even with the door left open. This had its own issues, like random animals showing up on the couch. The a/c I had didn’t even stand a chance. There is now a ceiling and insulation, so much of that issue is handled. I will be adding a vent fan and, budget permitting, a mini-split heat pump. Mostly the heat pump will be for me. A check of the spec sheets on all the gear indicated we were well under the too-hot mark. If you don’t have temp specs, you can check the equipment itself. Lick a finger and touch it to a transistor. If it doesn’t sizzle, you are good. If it sizzles, you are close to the limit. If you don’t get back all of the finger, then it is too hot and you need to cool things down.
You might thought I have forgotten poor ol’ Will. No, I have been busy and I think Will is now leaning toward grid tie. He has such a big load and the whole purpose of going solar was to save money when he retires. Grid tie can be a whole bunch cheaper than going off grid. In his case, if the grid goes down, he has a whole house generator that kicks in automatically. That gives him a low power bill and a backup supply.
I will continue with the answers, though, because, regardless of the size, many of the steps and advice in this series of posts will be the same for most off-grid situations. It is just a matter of scale.
We previously determined the load, how many panels we need and how many batteries we should have. Today we’ll go over the charge controller(s) that you need to get batteries charged safely.
Except for a super cheap shed system, I almost always recommend a Maximum Power Point Tracking (MPPT) charge controller. Heck, I even put an MPPT charge controller on my new Boxcar Solar system. What’s that all about and what are the advantages?
If you look at the label on the back of your solar module, it’ll have an open circuit voltage that is at one level and a maximum power voltage that is lower. That is really only valid at full sun. If it is overcast, the open circuit voltage may still be pretty high, but the maximum power point will be completely different. The brain in the MPPT charge controller constantly tinkers and adjusts to find the best charge. Not only is that a neat trick, but you will typically end up getting around 30% more power from your panel. That’s something on the order of getting extra free panels, but without having to haul them up onto the roof.
Another neat trick of the MPPT controller is that you can use a higher input voltage. There are all kinds of advantages here. First of all, you could use a cheaper “24v” panel on your 12v RV or boat AND the higher voltage will start the charging sooner in the morning or under cloudy conditions.
Remember, too, that John sometimes has some odd panels from grid tie service that have weird voltages, but they are dirt cheap. I bought a pallet of those 70 watt, thin film panels he sell for a dime a watt. They output 96 volts! You know how a lot of people will test a 9v battery with their tongue? Don’t do that with these panels!
I have 4 of them in parallel on the boxcar. (It is really a 40′ shipping container that looks like a boxcar) The 96 volts goes into the charge controller and comes out as 12 volts to charge the lighting battery. The panels are flat on the roof and in a forest, making for a challenging installation, but it works.
You can also use less wire. Solar wire is often 10 gauge, which in 120v service is good for around 30 amps. If you run 30 amps at a lower voltage you get substantial voltage drop and power loss that can only be cured with more or larger cables. For Stan the Hermit’s system, we put 4 large panels in series-parallel on each downline to his charge controllers. 4 panels do not exceed his power limit and only use half the capacity of the cable, so losses are low.
Now, what about the controllers themselves? They come in all sorts of capacities. I have 4 60 amp controllers on my system. John sells a 250 amp controller that I know of and I think a larger one. In some ways it might be better if I ran the one controller because then it would have all the knowledge of conditions and all the control over the charging. I got in the habit of using multiple controllers for redundancy on my sokar expedition launch and that turned out to be a good thing one time when some rough water nearly sank the boat and killed one of the controllers
In my home system, on a cloudy day or early in the morning, all of the controllers are running flat out to gather power and that is a good thing. Come 10 a.m. on a clear day, it can be possible to have too much of a good thing. You should only hit your batteries just so hard (the C rate) and I have enough solar to hurt the batteries.
I solved that situation by leaving one controller, my nice FlexMax, at factory setting and then step down the ratings of two of the others. That way, when we get into the range of bulk charging the two shut down. I go out at 10 a.m. on a sunny day and the two might be at or near zero output if the load is light. If I turn on the electric heater in the control room, then the dormant controllers spring to life, providing the extra 70 amps DC to the inverter to run the heat, but no more to the batteries.
Some of the newer models have a feature that let you link the controllers together so they can effectively think as one. That’s great, especially if they have a menu item where you can specify just how much battery capacity you have available. It is always best when the system components are working together.
On a system the size Will would need, you’d use the biggest controller you could find and use enough of them to have all that power covered. And, really, the same goes with smaller systems like mine.
I think I mentioned early on in this series that the higher your system voltage is, the more efficient you will be with your charge controllers. Here are some examples. The boxcar system is 12 volts and uses a 40 amp controller. 12 X 40 yields only 480 watts. If used in my 24v boat, then the same controller could handle 24 X 40 or 960 watts. On a 48v system I can run 1920 watts through it. Think how much money you can save buying one controller instead of four!
One last thing I should mention is that MANY, if not MOST, of the inexpensive “MPPT” controllers sold on Ebay and Amazon are not really MPPT controllers. Some are pretty good Pulse Width Modulated (PWM) controllers but not true MPPT. Some are dangerous. There are some bargains, but if you want to make sure of getting good gear, talk with one of Sun Electronics’ sales engineers and they will fix you up with the good stuff.
Going through this morning’s online solar newsletters, I saw some new products that are on the way. This is not at all unusual, but a couple of these things made an impression.
In solar modules, Trina is using bigger cells, but slicing them up and arranging them so you can get 500 watts from a panel the same size as a standard 72 cell unit! Wow, and to think I was drooling over 435 watt panels for my solar yacht! 500 watt panels would give me 4500 watts, which could come in handy to run the bigger motor that it seems I’ll need on my 6000 mile trip. No, I don’t think they are available, yet.
Another thing, a bit more mundane, is a new panel mounting system. Oh, somebody is always coming up with some new kind of clip and maybe I should do a post showing some of what’s in our media library sometime. This new thing is totally unique, though.
Are you familiar with seamless gutters? Bear with me, my mind has not wandered. The contractor arrives with a roll of metal and if you need a 40′ section of gutter along the garage, the roll of metal is run through some forming tools and out comes your 40′ section of gutter. This new solar panel mounting system works pretty much the same way. The trailer is pulled up to your house, the guy on the roof calls down the lengths of mounting channel he needs and the person operating the machine starts cranking out custom lengthe mounting rail. The result is a lopsided U shape channel with ledges at the top. You bolt this to the roof with the higher side down. Then you mount another at the appropriate spacing. Set your modules on the ledges and clamp them down. The channel area is your metal raceway for all the wires.
Neat idea. There’s always something new under the sun.
You know the old saying about one bad apple causing the whole basket full of them to go bad. The same thing applies to batteries. I am there, now, and so is Mark. Like me, Mark seems intrigued by the Simpliphi lithium batteries, but is also interested in getting a little more life out of what he has. Here’s his note.
Ok, since my 8 Rolls L 16 batteries are 8+ years old, all but one (one cell is 20) are reading good PH, would it be better to get 1 battery new or replace with a Simpliphi? How much do they cost and how many would I need for a 24vDC, 3KW 220 volt a/c system used as a backup on house? It’s the old array and battery bank, we have since added a separate grid intertie array but like both.
We will first consider stretching the life of what you have. I am all for that, but I would NOT buy a new one to mix in with the 8 year olds. Have you given them a good, bubbling equalizing charge? Sometimes that will bring them back.
It may be that you can find a good used one at an industrial battery dealer. Stores like WalMart and Target use L16s in the floor scrubbers and trade them out. Maybe you could pick up a used one, and one that is a better match, for a hundred bucks or so.
Another option would be reconditioning. Here in Pensacola we have an outfit called Battery Guyz that will sell a reconditioned golf car battery for $60 with a one year warranty. Reconditioning includes desulfating, washing them out and refilling with fresh acid. Maybe an outfit like that could refresh your L16.
Now, as far as replacing one of your L16s with a Simpliphi…NO! The L16 is 6v. The Simpliphi is 24 or 48v, depending on the model. You can replace your entire collection of L16s with Simpliphi. Could you keep the one good bank of L16s and run parallel with Simpliphi? I don’t know the battery well enough to answer that question. I have the same question myself as I have two 48v EVs running in parallel to my house banks. It is a possibility I would look into by contacting the company. From what I read about the Battery Mangement System (BMS) I think it is a possibility, but you would probably have to separate the L16s offline when you equalized.
Let’s assume the worst, that we’ll have to swap out them all and start with his L16s’ specs. 8 of them on a 24v system is two strings. Depending on which version he bought, they are good for 390 or 445 amp hours. Let’s just round off to 400 since I hate math. 400ah x 24v x 2sets=19,200. Call it 20kw. Now, you can only safely draw down 10kw, so to replace the entire set of L16s with the Simpliphi 3.8kw units, you’ll need 10/3.8 or 3 of them. Because of all the rounding, they may give a little more drawdown than the 16 Rolls. One Simpliphi, I think, weighs less than an L16, and 3 of them will take up a whole lot less space.
Here’s the kicker. The Simpliphi is rated for 10,000 cycles. That’s more than any other lithium I have seen. 10,000 cycles is 27 years. If you are my age, then that is a “forever” battery. And no maintenance.
You’d have to get with Roberto or Tony for some hard prices, but I would guesstimate that 8 shiny new Rolls L16’s, a premium brand, would set you back around $3000, especially if you throw in postage on those heavy beasts. I think the retail on the Simpliphi is around $3000 each. So you end up paying maybe 3 times as much for 3 batteries as the pile of L16s. Yikes! BUT, now you have more capacity, less maintenance, and may never have to change a battery again. Oh, and bet that if an L16 is $350 today, it will be more 8 years from now!
It’s a bunch of money, I know, but if I am running the numbers right, that sure sounds like a bargain to me. Call Sun Electronics to get up-to-date numbers and an actual quote.
Note that earlier I ran the numbers for 16 batteries instead of 8. That gave a completely whacked comparison, but the conclusion remains the same.
His old 12v system, pictured above, is really getting tired. It consists of nearly 50 mismatched modules and two windmills in parallel on a single overworked charge controller! His new 24v system is running, but only half-installed and there have been issues.
After our little troubleshooting session the other day, Stan-the-Hermit left the cabin on the creek for a few nights on the beach. He’d returned to the creek to find his batteries were full for a change. Of course, to zing me, he started out like there was some kind of problem.
Best news of all, for the first time ever, he ran his well pump and got all of his tanks charged up so he could bathe. Normally he has to fire up the generator to run the well pump, but it started and the charge held until all four of his tanks were full and the pump shut off. Given that his inverter is of the modified square wave variety, that’s quite a feat, as motors tend to prefer sine wave inverters.
To review what happened, Stan THOUGHT he had 5 of his 10 300+ watt modules connected in parallel to his 60 amp charge controller. Owing to a bad MC4 connector, 3 of them were actually NOT connected. Just as well, because all 5 of them would have exceeded the capacity of the charge controller. We replaced the connector and reworked the arrangement to two series pairs of panels, which reduced the amperage (and loss) on the downlines and gave the controller a little more voltage to work with in the morning and afternoon.
He swears he will finish wiring the rest of the modules and return my big roll of wire. I hope he remembers that if his 60 amp charge controller isn’t big enough for 5 modules, then his new 40 amp controller won’t handle the remaining 6 modules. I’ll be expecting a call next time the sun comes out.
I knew there was trouble as soon as I saw the Caller-ID. Stan’s system has been under performing, partly because he doesn’t have a decent battery and partly because half of his panels never got connected. Well, more than that, it turns out.
I loaded up my big spool of solar cable and a fistful of connectors and adapters and headed for Canoe Creek. You can’t get to his cabin in a straight line. No, you have what seems like miles of hill and dale and switchbacks. Florida is reputedly flat, but not along Canoe Creek. I know to take it easy and asked myself when was the last time the pickemup got new shocks.
I finally arrived and was delighted to see he was wearing pants. That was probably more in deference to the cool weather than knowing company was coming. If the weather is warm and there is nobody to complain about your wandering around in your shorts, then why not?
One thing I knew I wanted to do from the beginning is put the panels in series pairs to get a little more voltage to the MPPT controllers than just hanging them all in parallel. His is a 24v system so you can get away with it, but I like my way better and he’ll have less loss than trying to run 40 amps through a 30 amp wire.
Remarkably, he got away with just that sort of stuff for years on his old 12v system, which still works.
Stan has more ladders than anybody else I know, so there was one handy to go up for a better look. Just a word of advice here about old fiberglass ladders that have been left out in the weather. They sprout little glass fibers that will cause you to itch like mad if your bare arms come in contact.
First thing I noted was the panels were dirty. OK, mine are, too, so don’t count on 100% of rating. I cut the cable ties loose so I could see what was going on. Two panels were in parallel on one downline and 3 more were on another. Technically, he was running too much power into that 60 amp charge controller, but not really. There just wasn’t that much power. Stan was telling me that at high noon on a clear day he was getting over 500 watts on the meter. These are 305 watt panels. Five of ’em. Dirty or not, there should be more power.
I paid attention as I dismantled stuff. First of all, I cut the switch to the charge controller. That’s what it is there for. Pulling MC4 connectors under load can draw an arc and either burn up the connector or even burn you. So, for a few minutes, I was up and down the ladder, switching off and on and reading meters. Stan could have worked the switches and meters, but I wanted to see for myself what was going on. Know what I mean?
About the right amount of power was coming in on the one downline and not a thing was coming down the other. One of the MC4 connectors didn’t look quite right and it was indeed bad. Maybe it was corroded or maybe it was burnt.
“Well that’s one I got from you!” Stan declared. True. He got it out of my junk box. What happened after I took it out of service was beyond my control, yet the problem was MY fault! Stan must be related to my wife. They think alike.
I cut off the connector and put on a new one and he was back in business with 4 modules instead of two. That’s got to work better. I barely had enough time to get to Pensacola for something I wanted to do, so I told Stan to just copy those pairs 3 more times and he’d be done. I even drew a picture.
Moral to the story? Get everything out so you can see how it is connected. Check every connection. Don’t assume anything. If something seems wrong, maybe it is.
As for finishing up, Stan decided to go to the beach, instead. He still has my roll of cable.
Yes, it HAS been a while since the last post. This time of year just seems to keep me busy.
Last update on Will’s system we essentially concluded he is going to need a huge battery. Batteries should not be a system afterthought. They are probably the most important and expensive part of the system. Do it right and you can minimize having to do it again, unless you can find a “forever” battery.
I know Sun Electronics has several kinds of batteries, because I have been there and seen them. And bought them. The thing is John has all kinds of stuff that never gets shown on the web site until they have a closeout sale. I bet John doesn’t even know what lurks in the back corners. Sometimes it doesn’t hurt to just call them and tell them your situation and maybe they’ll surprise you.
Well, in a conversation with a fellow who got a quote from Tony for a pretty substantial battery, I learned about one that is real interesting. Understand, MY interest because right now I have one bank that is well on its way to ruin and others that are pushing up to 6 years old. I need batteries myself. Golf car batteries are generally considered beginner batteries and the better stuff can cost a lot more. Better can last a lot longer, too, making the expensive stuff cheaper. We’re talking about quality, here.
Well, here’s this lithium battery, the Simpliphi 3.8. It comes in 24 or 48v configuration, 3.8kwh. It is the good kind of lithium, that is they don’t burst into flames. It is much lighter and much smaller than conventional batteries, so if you need a really big (capacity) battery, you don’t have to build a new wing on the house to hold the battery. Apparently the built in battery manager (BMS) let’s you use it like any other battery and, in effect, go to 100% discharge of rated power. The BMS holds the necessary reserve to keep from harming the battery.
So, with a lead acid battery you strive to use less that 50% of capacity to maintain better battery life and the Simpliphi lets you use 100%. That means you have an even smaller pile of batteries in the power room. Throw in a lot more useful cycles (around 10,000) and this battery starts to look economical if you take the long view.
Unit size is 13.5″x14″x8″ and it weighs about 78 lbs. 3 of these weigh about the same as 3 1/2 Trojan T105s and have the usable power equivalent of around 16 of the Trojans! Wow.
It seems there are wall brackets available to fit these batteries, too. Compact, long life, neat installation, no hydrogen or acid fumes and long term economy. What’s not to like?
If you have your own solar power system, you literally own the power company. Heck, you ARE the power company. It can be a big chunk, at first, but over the long term you should save some big bucks. Like the big power company, you’ll have maintenance costs, but at least you won’t have to replace 10,000 poles next time a hurricane or ice storm rolls through. The big power companies know that solar is the cheapest power source now, so follow their lead!
I own another power company, too, or at least some shares of it. First there were shares of one of the local power companies. The GOOD company, not the one that supplies me. Then there were shares in this hot shot company that is buying up other power companies and installing solar farms all over Florida and other places. Then they bought the local power company.
The “financial advisor” says I need to sell some shares. I have too much. It upsets the balance. Maybe sometime I will sell, but here is a company that is making money hand over fist while investing in loads of solar power. Just imagine the profits they’ll have when they finish all the solar farms, quit buying coal, quit buying natural gas and use up their last nuclear rod? Sell? No way. They pay good dividends.
I think it was Don Lancaster who suggested this sort of investing to pay your bills. Invest in what you use. You eat, so invest in a profitable food company. You drink, so invest in a beverage company (this has been the crown jewels in my family for over a century). You wear pants…and so on. So why not a power company? Since most power companies are keen on solar for THEIR use but don’t really want you to have it, wouldn’t there be a sweet irony to you using their dividends to build YOUR solar power system?
Well is there a future in power companies? Some thoughts there: Yes, because not everybody can do their own solar power system. Yes, because as electric cars catch on they’ll need power, too. Yes, because we keep finding more ways to use more electricity. Yes, because they get rate hikes tied to costs, so they are guaranteed to make money.
I don’t use much power from my grid provider, but they charge a lot anyway, because they are corrupt and inefficient. I’ll pay the bill with my dividend checks from the other company. I’ll also keep making most of my own electricity and maybe get to spend what I don’t get billed, assuming I ever quit expanding the system! Maybe I can just put that expense down to “entertainment”, because I really enjoy this stuff!–Neal
Will needs a big solar power system for his big house. We figure he has the perfect slab of roof for installing enough solar modules. Now, since he wants an off-grid system, we are going to think about a battery. A really BIG battery.
No, I have not forgotten about Will and his new solar power system. It’s just, well, holiday season, firewood cutting season and working on my own system season. I have been thinking about it, though, and I’m thinking I’d hate to see Will completely leave a perfectly good grid. But is it a perfectly good grid?
Lots of places in Texas, where Will lives, give grid-tie folks net metering and some that don’t at least don’t try to punish you for having solar. If you have a good power company you can put together a system that will take care of most or all of your power consumption and you’ll still have the power company as a backup. Maintaining the connection to the power company can cost a bit, but it could save you a good bit of expense in your power system, like on the size of your battery bank.
Warning: Your power company might change the deal at any time. It happens all the time. I just saw where one power company figured the value of your grid tie solar power at nearly 8 cents, yet they decided to pay 2 cents for it and charge you a bunch if you buy it back. They might also tack on an extra $50 per month or more just for the grid tie connection. Grid-tie, traditionally did not give you power backup if, say, the power company shut the power off for a week to prevent forest fires. We have ways around all of that, now. We can interact with the grid instead of intertie. More on that later.
Will’s motivation is to save on expenses when he retires. Smart move. What I am going to suggest is a path where he can keep the grid for a backup and eliminate most of the power bill OR cut the cord. It is the same equipment and following this path, except you have more or less battery expense. Your solar panels will provide all of the house’s power, if all the calculations were right, and you can cut the cord to the power company when you are confident about the system.
Let’s start out, though, just planning our battery size for going off grid. I find that being able to go 4 cloudy days is a pretty good reserve. On a cloudy day, you might only get 10% out of your solar modules. If it is cold then the batteries might get a little sluggish, too.
I came upon the number 4 because that is how long the grid was down after a hurricane when I was building my house. Only basic circuits were included in my battery backup system and that worked fine until the hurricane with a 5 week outage! I do sometimes see 5 or even 6 dreary days in a row, but that is rare. Think about how many days of reserve you need for your location. For our purposes, here, we’ll calculate for 4 days.
Back in Part 2, we estimated that Will uses around 3000kilowatt-hours (kwh) a month. He’s going to need a 48 volt system, for sure. There is equipment with higher voltages, but it is rare. 48 volts will keep the amperage at modest levels.
OK, 3000kwh per month divided by 30 days in a month gives us 100kwh of power per day, or 400kwh for our 4 day reserve. Divide 400,000 watt-hours (remember, those were KILO watts) by 48v and you get 8333.33 amp hours of battery. See that huge battery at the top of the page? I think that one is 3000 ah. If you haven’t had an OMG moment, yet, consider it really hurts a battery’s lifespan if you drain it down below 50%. So we double it and round it up to 17,000 ah. OMG!
Don’t panic, yet. That 3000ah battery up top belongs to a fellow named Daryl. Daryl has a chain hoist and a gantry to get it tucked into the house and a forklift to move it outside. Daryl is kind of an exception with the equipment he has around the house.
You can buy 2 volt cells with lots of amp-hours that one person with a hand truck can move around. There are also modular racking systems. It is going to take some space and I’m not talking along the back wall of a typical garage, unless you leave the car outside. No, this is not one of those dinky little Tesla Powerwall toys.
There are many choices in battery types. We hear a lot about Lithium these days. They are probably the most expensive option, but they are a lot lighter and you can discharge them deeper without hurting them, so you don’t have to have quite such a large battery. On the other hand, they require a battery management system because running the battery down too far JUST ONCE can ruin it. The best thing is they are sealed and require no maintenance.
Pocket plate Nickel Cadmium, or NiCad, is another expensive option, but these batteries are hard to break. Unlike the NiCads we used to see in power tools, these don’t lose capacity owing to “memory effect.”
Nickel-Iron Edison batteries were so good they quit making them! There are 100 year old batteries still working. The only maintenance is to add water and maybe wash them out every few decades. You can run them completely down and ignore them for years and they’ll come right back to life. They were still made in eastern Europe and China and are now back in USA production. I have been told they have a higher self-discharge rate than other batteries, but have never seen it in a spec sheet. This is as close as you’ll probably get to a forever battery. Pricing is along the lines of Lithium.
Lead-acid batteries are most common. They come in both sealed and open varieties. Flooded, or open, batteries are fairly tolerant of abuse, but require regular service in the form of adding distilled water and neutralizing acid mist. They need good ventilation as they produce hydrogen gas. They come in relatively small and cheap units in the form of golf car batteries or large and rugged industrial cells, as you see in the photo of the red Rolls battery, above. These batteries have thick plates and large electrolyte reservoirs for long life.
Sealed batteries do not normally require any service and can have a very long life. They can be damaged by charging them too hard, though. Make sure to use the appropriate setting on the charge controller.
Regardless of battery type, in a system this large it is possible to have a charge rate that can damage the battery bank. If multiple charge controllers are needed, it may be best to use a controller family that can be linked together to coordinate the charging. I don’t have that with my 4 charge controllers, three different models, but can set the parameters differently on each one to allow for a more modest charge rate.
Here is another consideration of going off grid. You have to have a certain amount of kilowatts coming in to meet your living requirements, but you have to have a battery that can handle all of those amps and watts coming in.
Let’s say we have panels that can put out 200 amps and one string of the Sun230 batteries. 200 amps into a 230 amp battery is charging at almost a charge rate of C1. They are great batteries in their size class, but at C1, they’d melt. Quickly. These batteries are probably best charged at C10 or C20, or a whole lot less than 200 amps. 8 or 10 strings of these batteries would take the charge just fine, but you really should limit the number of batteries strings (groups) because minute differences can cause them to fight each other.
200 amps going into Daryl’s 3000ah Bull Dog battery would be fine. Will’s system is going to make a bit more than 200 amps, so there we are back to another reason to have a humongous battery.
But maybe it doesn’t have to be quite that big. If you keep your grid connection and use a hybrid inverter, you can set it to provide the power when the batteries have it available and automatically switch over to grid power when they don’t. With a relatively small battery, you could run around the clock in good weather, with low a/c demand and pull from the grid if you have one of those long dreary periods. Will has another ace in the hole I’ve not mentioned. He has a natural gas whole-house generator, so the generator could take up the slack in cloudy weather.
Since he has the generator for backup power, there is a way of going grid-interactive without spending as much on the system. That involves the use of Zero-Export Grid Tie. I don’t think that’s the best name for it, but that’s what we have to work with for now. This lets your solar panels reduce your grid power consumption without incurring and Grid Intertie fees that would negate the savings. These can be equipped with batteries, too, to extend the savings into the night. I just commissioned such a setup this morning on the little bit of my house that is on grid, so I can’t yet address what kind of savings you can expect there.
Some lifestyle modification might help on the size of the batteries and other system components. Can you operate the pool pump only during the day with a timer without it turning into a swamp? Better yet, could you just fill in the hole? Snapdragons and Dianthus would be lovely this time of year. Pansies, too, if not exposed to rain and sleet. Will probably likes his pool, but a lot of people do fill them in! It is probably where about $100 of his power is going, too.
Also on the pool, if you have a heater and you have natural gas, I hope that is what you are using. Better yet, solar thermal heat. Super cheap and efficient!
Anyway, I have rambled on a bit long, but you should be able to find some things to consider in there, too.
We can talk about charge controllers to charge that big battery next time.–Neal
Take a good look at the photo. These guys are going to lose space for an entire panel because of a vent pipe poking up through the roof. Why are there vent pipes? Because when you use a sink or any other water source in the house, it needs to be vented to drain properly. The vents stick out the roof because clean water is not the only thing that goes down the drain. You don’t want the aroma of your septic tank or sewer line in your attic.
Why is it on the roof? Plumbers put a vent for every drain cluster because it is easier and cheaper for them. I don’t like holes in my roof, so I went to the expense and effort of plumbing them all into one vent. My roofer dude tells be there is a gadget available so you don’t have to have ANY vents poking through the roof. It is basically a check valve that lets air into the line when you pull the plug on the bathtub, but does not let the stinky fumes out. These guys (or the homeowner) could have eliminated that vent, gaining a few more watts and a better looking installation.
Next, put your modules up in order. That saves having to walk on the glass. Glass is slippery, (more so when dusty) which is a danger to the installer. Most panels are not made to support a lot of weight, either. At least where this guy’s foot is, the frame is taking most of the load. Oh, and a suction cup would have made it easier to get the bottom end of that module brought up even without risking a finger.
Finally, why not give the panels a wipe down before installing them? Rain won’t necessarily wash all of that off.
Otherwise, things look pretty good. Two rows, mounting on good hardware and walkways for future access.
Just a quick tip coming from experience. I was out in the Solar Shed, today, pulling wire to add a couple more panels to my Non-Export Grid Tie experiment. I’ve been running 1200 watts, being shared by two GT inverters. Now it is 1800 watts. Soon, it’ll be 2400 and live on the grid instead of in the lab.
I have the giant spool up on a rack on the back of one of my electric trucks so I can point myself in the right direction and run with the end of the wire. Apparently I have been doing that a lot, because I am starting to see the core. I checked the number on the side of the spool with the number on the wire and, yep, getting close to 1000 feet that’ve been used. The Shed is 80′ long, now, so some of the wire pulls are pretty lengthy. I had hoped that spool would last me through the next addition to the Solar Shed, but looks like I’ll have to buy another spool. Tip: write on the side of the spool the first footage number you find on the wire so you can keep up with how much you’ve used and make sure your vendor is straight with you.
I rummaged in my parts drawer and found MC4 splitters and enough connectors for the job, but not enough for the next and final step to a total of 8 modules on this project. Then it dawns on me, using the splitters I’ll have too much current on that #10 wire, so that means perhaps another 80′ of wire. AND, naturally, I didn’t have enough pins for the connectors. As I progress with the Shed, things are gradually getting more organized, but there was difficulty finding the sack of MC4 connectors I knew I had recently (sometime this year) bought. I finally found them and was in business. Hooray! When I finished, I put them in the new parts bin, an old lateral file from Goodwill. Lateral file cabinets are showing up everywhere as businesses put everything in digital form in the “cloud”. A friend paid $15 for one, I think, and they told him they had a bunch more he could just have at no cost. They are wonderful for storing parts. I have plastic tote bins in mine to separate the parts.
You can, of course, buy pre-made cables, and they’re fine if they come with a kit, but do you really want to stop your project and order stuff every time something turns up a bit short or you make a change? For a bigger system, you’ll also find buying wire and cable in bulk can save a bunch. I’ve bought the big 1000′ spool of solar wire, full 100′ spools of 00 and 0000 cable, sacks full of MC3 and MC4 connectors, and buckets of terminal ends for battery cables. Yeah, it hurts really bad when you buy a big spool of cable, but ultimately, it hurts a lot less than buying by the foot or by the finished cable. Not only that, it gives you the resources to make changes or additions when you are ready to do so and not when the postman or UPS dude brings your small order two weeks later.
It’s also good to have some spare hardware when Stan-the-Hermit comes buy looking for some stuff for his system. He may be too late to get into THIS spool of wire.
We now know a bit more about Will’s roof, his power consumption and what he wants to do. Let’s get started…on some Texas-sized solar power.
I’ve been in contact with Will and he supplied some more information. If you read Part 1, you know he wants to go with solar power, but that leaves a lot out. We now know that he has a big house, 3700 sq. ft., and pool. He also has a Texas-sized power bill and wants to go off grid before he retires.
Let’s start with his power bill, a bit over $300. We don’t know the kilowatt-hours he uses, but we can come pretty close from the bill. “A bit over” can cover the base fee, leaving $300 even. Another Texan, Donald, tells me his power costs a dime per KWH. So .10 into $300 gives us 3000 KWH.
That’s a bit more than most folks, but I am told a pool can take up $100 worth of power. I don’t know much about pools, but I am aware there is a pump and often a heater. I wonder if the pump could be put on a timer to only run during the day when the sun is working? I don’t know how Will is heating the pool. I know he has natural gas. That’s the way to go OR use a solar thermal heater. That is relatively inexpensive and there is no fuel cost.
Regardless, 3000KWH divided by 30 days in a month, gives you 100KWH of power per day of consumption, which is an easy number to use.
We don’t know his average hours of insolation (not inSUlation), but he can look that up on numerous websites, but lets go with 5 hours, as he is at a similar latitude to my place. Divide your daily 100KWH by your presumed 5 hours of full effective sunlight and that means you need 20KW of solar.
When we say 5 hours of insolation, you know you’ll be getting a little bit at 7am, a lot at noon, and a little at 5pm. That’s 10 hours of some amount of sunlight and factors in the average and some cloud time. It isn’t perfect, but you have to start somewhere!
If you find a deal on 250 watt panels, divide 250 into 20,000 (remember, it was 20 KILO, or thousand watts) and that comes out to be a whole bunch…80 panels. Oh my, that’s gonna take a lot of roof. Let’s run that again with some of the newer, more efficient panels. I have some 300 watt panels that are the same width as a 250 and maybe and inch or two shorter. 300 into 20,000 gives us a need for 67 panels. That’s a lot less, but still a bunch. 400 watt panels are becoming more common. I saw where one company just announced a 440 watt panel, but I doubt you can buy them yet. Let’s try 400 into 20,000 and you get a more manageable 50 panels. However, these are going to be bigger panels.
We’re now at the point where an old boss of mine said we’d “play with paper dolls.” This was before computer CAD programs. We’d take a piece of graph paper and draw out the roof, in this case, to some convenient scale. Next, using the same scale, we’d cut out 50, or 67, or 80 paper panels to scale (starting out in strips) and then start shuffling the paper panels around on the paper roof to see IF they’d all fit and HOW’d they best fit. A good scheme is to butt together two rows, skinny sides together, then leave some walk space, unless you want people walking around on your panels. If fact, I think the Code now requires that you leave some walking around room. In two row sets you can get at them for troubleshooting or service if you should ever have a weather (hailstones or hurricanes) or electrical issue (lightning, hotspots, hungry squirrels). If you use CAD at work, then you are already prepared to make a roof model on your lunch hour. There are even free CAD programs that you can download and learn to use at home. We didn’t have CAD when I went to engineering school, so I am comfortable with a pencil and a bit of graph paper, but I designed a bunch of computer stuff using CAD, too. Your choice.
Looking at a sketch of Will’s roof, it seems to be 69′ long and facing south. You couldn’t ask for a better start! Let’s see, those 300 watt panels are a meter wide, let’s call it 40 inches. 69′ is 828″. 828 divided by 40 is about 20 panels wide, not counting a useful walkway. One thing that concerns me is a dashed line. I’m thinking that represents something like we have at Mom’s house. There, you have one level of roof over the living area, then it steps down 2 feet across the double carport and the garage. If there is a stepdown, depending which way it goes, there’s going to be some shading going on early morning or late afternoon. You’d best leave some panels out to avoid the shade. Shading a panel can do more than just reduce your power. We won’t talk about that right now, but it isn’t a good thing. Let’s assume a shady area and leave a panel or two out for a walkaround.
Can we do more rows, because it looks like we’re short? Yup, he has 24 feet of slope. Let’s just say a solar module is 6′ tall. Most aren’t but that’ll give us some margin. 3 rows is then 18′, leaving 6 feet to divvy up for walkways. Let’s just say we took out two panels for our presumed shade, leaving 18 to the row. Three rows make room for 54 panels. Not enough for 300 watt panels, so we might want to consider the 400 watt class. Download a spec sheet to make your paper dolls, either the literal kind or the virtual ones.
Oh, but no worry. Aside from that long stretch of 24 feet, he has an extension in the middle. It is 16 x 24, which could give him maybe 3 more rows of 4 panels, bringing the total to 66. We have this licked!
Ok, understand that solar panels are rated for certain standards for conditions. Unless they are on a mountain top, free of haze and running cool, they are not going to put out full rated power. Also, understand that things may change and you’ll want more power. Think ahead and leave yourself some margin.
What I am thinking here is to fill every one of those rows up with 335 watt panels, assuming the scenario I have described will play out. Where’d we leave off? About 66 panels? 335 watt panels are cheap and plentiful and 66 of them will make (ideally) 22KW. Multiply by 5 and we have 110KWH, giving us a 10% margin. Hey, if you can get more up there, go for it. Trust me, except when it comes time to write the purchase check, you won’t complain about having more than enough power.
OK, we’ll leave Will to check the numbers for how many he can get up there without shading and check on walkway requirements in the local code. I think this will work.
Next time we’ll talk about something else that is very important: the big, ginormous battery. Will’s going to need one.
The Texas-sized power system in the photo at the top of the page comes from Daryl T.
UPDATE: Wouldn’t you know it, I say 335 watt panels are cheap and plentiful and then find John is out of them! He has plenty of 320 watt panels, but I think 66 of them will cut it too close. The big surprise is the deal on some of the newfangled half-cut 385 watt panels. They will give lots of margin and cost less than the 320w modules! Available in pallets, only, but Will is going to need pallets. Call Sun Electronics for a spec sheet to get the size.