Battery Connections Illustrated
Elsewhere in the blog page is a post about battery safety. I have a couple of battery photos to illustrate what I was talking about the other day, easily making battery polarity easier to see. The old 24v battery strings have decent cables, grease to seal out corrosion, but they are a bit dirty and it is hard to see the polarity, should I need to reconnect anything. You can see where I marked the 2 gauge cables + and –.
The batteries do get cleaned up every time I add water and it is about that time.
Here’s the new set for the 48v system, with painted corners to mark polarity, color coded heat shrink on the 2/0 cable terminals, dates on the batteries, grease on the seal and the terminals. This is much easier to identify things. In lieu of shrink tubing, you can get electrical tape in different colors, too. Batteries are the SUN230 golf car style from Sun Electronics.
When the new wall goes in for the power room, I will build a proper battery box to keep out the dust and dirt. I use plywood and 1×2 strips painted with latex paint. My last battery box was nearly 30 years old with no acid damage because latex paint is acid resistant! The original battery rack was steel and was in pretty bad shape after those years. I have gone to wooden racks and they seem to work well. I’ve never had any worry about fire, but lining the box with latex painted drywall will ensure that nothing burns.
The floor gets painted with latex, too, and I put in a layer of vinyl flooring. I leave a dusting of baking soda on the floor, just in case, and keep a box or two of baking soda around to neutralize any acid spill. Of course, John sells sealed batteries if you want to avoid that issue.
By Neal Collier
In defense of crappy free solar roof tiles
John’s right, the quest for attractive and practical rooftop solar with these tiles was a flop. Some of it was design flaw and some of it was improper installation. I hope Mr. Elon Musk, who is marketing solar roofs, has investigated this matter lest his quest should fail as well.
Stan-the-Hermit poses with 10 conventional panels for his cabin power upgrade and 300 roof tiles at the old Miami Gardens store.
I know about the tile problems because I have hundreds of these tiles. No solar panel works well when it is hot. Screwing them to a plywood deck leaves no space for cooling air circulation, inviting poor performance, at best. The heat also affected the wiring, some of which was made with insulation that lacked the proper plasticizers, so it just crumbled away. The heat and a poor choice of sealant caused the glass to separate from the cells, on some, allowing moisture to corrode busbar connections. The way roof shingles are installed, you can’t just pull out a bad one and replace it. You have to remove everything above it to get to its 4 screws. If one of a string of 200 goes bad, then you have no power. And, let’s not overlook a worker’s ability to screw something up. Many of the tiles I got never had all of the screws installed and some had pinched wiring. Combine high heat, 600 volt string potential and bad or crimped insulation and you are just asking for trouble. While none of these tiles ever burned down a house, there were a few smokers.
Then, consider their deinstallation. Very few I have received did not have the imprint of a size 11 boot in the grime on the glass. They were walked on, stomped on, thrown off the roof and piled high, sometimes with screws still in them. A few were hit with hammers. The result was some broken cover glass and most have cracked cells.
Some recycled roof tiles may require adjustment before use.
So, why would anyone want any of these? For one thing, they are pretty much free. For another, even if they don’t work, you can cut off the wires and make a good roof for a shed or carport. I’d reroof my 50×64 barn if a container of duds showed up at my place. The thing is, though, a lot of them do work and making a few changes in how they are used can make them practical.
First of all, don’t put them on your house. That is a contractual term of acquiring them. A shed, lean-to or outhouse is ok. One guy was going to mount them on a radio tower! In shed construction you don’t need to use a roof deck. Put up trusses or rafters (the sloping bits) and string 2×4 purlins across them at the appropriate spacing and start screwing down the panels with deck screws. This gives cooling air circulation underneath. It also gives access to the wiring so you can simply bypass one that fails with an MC3 jumper cable. No muss, no fuss.
This is how I’d do it. Just sayin’…. Solar Shed, phase one. If you don’t need a shed, use shorter posts.
Easy access to the wiring. Easy construction.
Then, connect a modest number of these low voltage modules in series as appropriate for your charge controller. In my Solar Shed project, I use strings of 21 on the 30 amp MPPT controllers on my 24v system and 4 strings of 21 for my 60 amp controllers on the 48v system to which I am transitioning.
For a barn power supply and a water pumping station, I install two 4×4 posts about head high and two shorties, with 2×4 inclines between the tall and the short. The shingles are screwed to those. 3 shingles make about 100 watts at 12v with a cheapo on/off charge controller. You can add blocks of 3 to your heart’s content.
This easy setup runs my backup water pump at the far reaches of my property. 24 volt pump and no battery. A similar setup, with battery, lights my barn.
Back at the Solar Shed, on the first 16′ section I learned to avoid the panels with delaminated edges. They are trouble. I did not put up any with broken glass, but accidents happen and I have a broken one. It does not leak and it makes electricity. Because I have access from below, I have been able to jumper out two of the delaminated ones that quit. Their bypass diodes should have done this automatically, but it seems the heat was not good to the diodes. A $20 infrared thermometer gun lets me check for hotspots underneath.
The second 16′ section has had no failures. The new 38′ section, so far, does not have a single panel that does not contain cracked cells. Want to know a little secret? As long as the silver strands are intact, cracked cell perform better than whole cells? Will they last? Who knows. Live for today!
Phase 3 of the Solar Shed in progress, as of last week. The big panels are for the Solar Yacht project hardware evaluation. Yeah, a Phase 4 is planned.
Live for today! Phase 3 of the Solar Shed in progress, as of last week. The big panels are for the Solar Yacht project hardware evaluation. Yeah, a Phase 4 is planned.
Is it practical? You decide. I charge my fleet of two electric farm vehicles, reworked golf cars. They allow me portable electrical and mechanical power over the entire farm. I run lights and tools at the solar shed, even a 2hp air compressor. I welded up the solar jalopy with this power. All construction on the shed was done with solar power (the first section power came from my solar boat). A line goes underground to the house to the emergency power circuit I had for the generator and battery backup, so my lights, office and kitchen are powered by these crappy plastic roof tiles. That’ll be 11KW of cheap plastic power when the current section is done, which means free air conditioning this coming summer!
Take your solar power with you with an inverter-equipped solar-charged electric farm jalopy.
Building the bridge to nowhere with portable solar power.
In the unlikely event that all of the panels quit, I’ll still have a useful shed with a free roof. There are plenty of others who dragged these home. How are you using them? –Neal
You could void your warranty doing this stuff
It’s a beautiful, cool sunny day here in NW Florida and you’re right, John, you can knock a hole in a solar panel and it’ll still work. Just don’t try it with a hammer, because there is a tough plastic layer under that glass and another on the backside. You need to be forceful to get a hole. I started with a Suntech STP280 that got hit with a tractor. Yup, that’s a busted one!
The frame is bent, the glass is cracked, the J-Box and all the wires were ripped off, the cells are cracked and it has been left out in the weather for a few years. I soldered on some wires and new diodes, then I took it down to a safe place and wired it up to some batteries on the solar jalopy. It was making a decent charge
I had a little test in mind.
So I shot it with a .45 pistol and it was still making a charge.
So I thought I’d try to make a bigger hole with a 12 gauge “ring load”. Nice, but no change. So I went with straight bird shot and that was better. Then I backed up and gave it some more bird shot. Then I shot it some more with the .45. Hey, I could go broke on ammo before this thing quits!
Since I was out of ammo, I unhooked the batteries and connected an offroad driving light to it… it still works!
Now it is really busted up, but still runs. Hey John, is this still under warranty for output?
Now we know. Look for test results under the “Inquiring Minds” post.
By Neal Collier
Here we go again. Hurricane Michael is projected to hit our vicinity as a Cat 3 storm. Get ready everybody!
Hi John, John, you live in a glass tower, but out in the neighborhoods you can hear the generators buzzing after a hurricane has taken out the lights. 200 watts for the fridge and 50 watts for a ceiling fan and they’ve got those darn 3500 watt generators blasting away at 3600rpm. Dumb. Well, maybe not dumb, they just don’t know any better.
At my house, the ceiling fans have a slight buzz from the inverter in my backup power system, but I can’t hear it because I have the windows open and hear those generators a quarter mile away at the neighbor’s house. Listening carefully, I can make out 3 or 4 of them. Most are those loud, cheap ones from Home Depot or Lowes and most people don’t realize that you have to change the oil in them every 25 hours (50 hours for the better ones with a filter). That’s an oil change every day or two! Cheap air-cooled engines use a little oil, too. Do people buy a case of oil and some filters when they go out and buy 2 cans of gas in preparation for the storm? Nope.
After about 3 days the generator will probably quit, assuming enough gasoline has been found to run it. If it has a low oil safety shutoff, like most Hondas, the homeowner will scratch his head and wonder why the generator won’t run anymore. If he checks and adds oil, he will be back in business. A lot of engines do not have the low oil shutoff and they will soon die a horrible death.
That assumes, of course, that the owner bought enough gas to keep it running. How long will 2 cans of gas run a generator? Not that long. Maybe a day, depending on model and load. Try buying gas after a hurricane. I know of exactly one gas station with a backup generator. Some will have power and some will rig something up. Back around 1960 I saw a gas station owner running a gas pump with a Maytag gas washing machine motor. Yes, Maytag made gasoline-powered washers! The owner took cash for the gas. Who has cash today? Credit card readers and ATMs don’t work without power. Oh, and every one of your neighbors will be in line with you, so you will be spending some time getting those two gas cans refilled. Maybe you need more than two cans.
Don’t think I am knocking gas generators, here. What I am knocking is how they usually get used.
One of the most perfect home power systems ever made, made before power lines came to us country folks, was the Delco-Light power system. Everything in the house ran on (usually) 32 volts DC. When the batteries got low, you started the generator (some models started themselves) and it ran until it ran out of kerosene or gas (they’d run on just about anything) or the batteries were charged. The engine was a low rpm machine that would run just about forever. I have a half dozen of them and none are worn out. Moreover, engines have an operating range where they are most efficient and that is with a good load on it. A fridge and a ceiling fan do not load your generator at a point of high efficiency and, remember, it takes a certain amount of gas just to buzz that thing along at 3600 rpm, even if there is no load at all.
The Delco-Light power system. One of these used to power my blacksmith shop. I love their battery rack plan for those 2v cells.
So why do I seem to be drifting off subject. I’m not, I’m just setting the scenario for you to do a modern recreation of the Delco-Light to power your AC world, use less fuel and make the night a quieter place.
Here’s what you do. Take appropriately sized inverter/charger, a bunch of batteries and add them to your generator. (If you want to add in some solar panels, then good for you.) You can have the inverter wired in through a transfer switch or you can put a plug on it and plug it where you would have otherwise connected the generator. Now take the output of the generator and connect to the input of the inverter. 4 golf car batteries (I prefer 24v configuration, but 12v will do and your car can be the generator in a pinch) will run your lights and fridge for 24 hours. There’s probably enough power left over to fire up Mr. Coffee to wake you up and nuke something from Mrs. Stouffer’s kitchen to fill you up. Run the generator in the morning before going to work (or before you begin removing the tree from your roof) and again a bit in the evening, as needed, maybe even getting a little TV or A/C time in, too. The generator will run under load and not for many hours. Now you only have to change the oil every week and maybe the power will be back on by then.
There is a security side to this configuration, too. After Hurricane Katrina, many people in the city were afraid to show any lights and run the generator at night because predators would know where there was somebody with food, light and comforts. The generators were ok in the day because there was lots of activity to mask the noise. Do NOT run the generator in the garage…it will kill you. If you don’t want it stolen, chain it to the tree in the backyard when it is running and put it in the garage when it is not. BTW, a padlock and a piece of chain should be considered a standard accessory if you buy a new generator. DON’T refuel when it is still hot. Buy some extra oil and get more than 2 cans of gas. At the end of the season, put the gas in your car so it won’t sit until next season and get stale. No-alcohol gas is best and running the generator dry by turning off the fuel valve or just running the tank dry will save your carburetor from an early death.
Just some things to think about.g Update: Michael went east of us and just made an awful mess from the coast up to Georgia. Hopefully the rebuild will include solar, as happened with New Orleans after Katrina. Unfortunately, some areas were so devastated there was nothing left for solar to power.
John and I have been discussing options and strategies to have a stormproof shelter incorporated into your home.
By Neal Collier