PS This man is also a great and very entertaining and educated author. Oh, and grammatically correct, I’d bet he proofreads almost everything he writes , unlike me.
Here is something you may want to use. There will be a follow-on shortly.
What’s all this sulphation stuff, anyway?
Lead acid batteries, as far as I am concerned are the best bang for the buck in renewable power systems. If money were no issue, there is another type I might choose, but there are some mighty fine lead-acid batteries out there that would outlast me. Whatever batteries you choose, there are some pretty simple maintenance chores you can perform to help maximize the life.
Externally, you keep the acid wiped up and neutralized (I keep a spray bottle of baking soda and water for a quick squirt and wipe), make sure the terminals are tight and aren’t corroded (a little battery spray or even car grease works wonders) and keep the water topped up. I guess the water is supposed to be internal, but about once a month you’ll find that some of it isn’t and you’ll have to take your external jug of distilled water (from the grocery store) and pour it in. Yeah, you really don’t want to let the water get low if you want to keep those batteries alive.
Internally there is a really insidious hazard to battery life. It is called sulphation. You may see it spelled with an “F” in the middle, but I am old-fashioned. What happens is that when a battery is discharged, the chemical reactions start making sulphate crystals that coat the plate. The sulphate blocks the charge getting in or out, like putting dirt in an air filter won’t let air through. The longer a battery stays discharged, the thicker the layer of sulphate gets and the less your battery can do.
There are all sorts of electronic devices that claim to rejuvenate an old battery and most are useless. I have one that is plain dangerous, but it seems to help a little. There are some new-fangled battery chargers that have a “rejuvenate” mode that can help a battery if it is not too far gone. There are some online offers that tell you to put epsom salts or food preservative into your batteries. If you just have to, try any of these on the deadest battery you can find and don’t mess up an otherwise decent battery.
The best way of dealing with sulphation is to get after it before it causes permanent damage and the best tool is probably already in your power system. This is your charge controller! Most self-respecting charge controllers have a multistage charge process, which includes a desulphation or equalization cycle. Desulphation and equalization are not exactly the same thing, but if you do one you can take care of the other at the same time.
I have noticed that some of my charge controllers want to equalize every day, which can use a lot of water, but they don’t really equalize enough. I also know that my inverter gets very fussy about voltages in the desulphation range, so I take a bank of batteries and one charge controller and isolate them from the rest of the system so that the battery charging does not interfere with the inverter. My new system allows me to do this using battery switches to change circuits instead of shuffling cables. This makes it pretty much error proof.
My favorite charge controller for perking up batteries is the MidNite Solar FlexMax series. With it I can set not only the voltage, but the time. For a 12v system you need about 15.1-15.4volts. Double that for 24 volts and quadruple it for a 48 volt system. Since I only equalize a few times a year, I let it go 4-6 hours and then use a battery load tester to make sure it did some good. I normally leave the EQ voltage setting down at a level that doesn’t upset my inverter for those occasions the FlexMax might try to equalize on its own.
But what about those sealed AGM batteries? They are more resistant to sulphation, but more sensitive to some other things. I’ll talk about them another time. –Neal
Thank you Neal. Now to get it translated into Spanish and Creole……Pierre? Tony? I’ll work on that. Any volunteers? Like my staff even reads my blogs, ha ha, that’s a joke, sort of.