So a few weeks ago I was doing some reading about reconditioning lead acid cells using distilled water and Epsom salt.
I had a couple completely dead (registered 0.5v) 12v SLA's and I thought why not I'll see if I can at least add life to these old dead batteries. They were batteries out of an old electric scooter I got that had been sitting in someones attic for years. I shook them around and didn't hear any water in the cells. They would not take a charge, even from a bench power supply
I opened up the top of them then pulled off the rubber plugs. I added about 1/2 a cup of distilled water then heated it up. Then added about 1.5oz of epsom salts and mixed it up and let it dissolve. Then added some to each cell.
A hobby charger refused to try to charge the battery due to the low voltage. So I put the battery back on the benchpower supply at around 12-13v for an hour or so. I got the battery voltage to increase to around 12v then put it on the hobby charger. The hobby charger would only put a few mA into the battery before terminating at 14.7v. I parlleled it with another healthier SLA and managed to get a for mA more into it, then it terminated again and I repeated the process until I was able to charge the pack several Ah. The 2nd pack was more stubborn and wouldn't charge more than 5mA after this same process. I ended up overcharging the pack for 30 minutes or so using the 7 cell setting on my hobby charger. This allowed the pack to take a bit of a charge, and later on it was content with charging several Ah at the 12v setting.
Now these packs still have quite high resistance but I did manage to get them usable enough for some light usage.
I've heard other stories of people using epsom salts and it really helped their battery out. Their car would hardly start, then after adding it, and cycling a couple times, the cold craking amps doubled.
Pretty interesting stuff. Has anyone here played around with reconditioning Lead acid batteries?