Off Grid Home Forums Technical Discussion Insane battery system need help Re: Insane battery system need help


Dustoffer, I will be the first to admit desulfators are not a magic solution.

However I have also had sucess in some cases.

The original poster has a very unique problem. The battery bank is way too big for the available charge source. What the battery manufacturers are not telling us is there is a minimum limit as well as a maximum charge current limit. Joe’s problem is he cannot accumulate enough charge in a day to bring the battery bank up enough with the available solar panels. Consequently the bank is constantly under charged. circumstances beyond his control or even his knowledge compounted the situation.

You are right, adding one good cell into a bank of older batteries is not good. Its worse when the batteries are in parallel. With care it could sometimes be done when the cells are wired in series.

When I first had to deal with this kind of problem I always yanked the whole bank. After testing and recharging the batteries I kept the good ones for single battery use, and junked the rest. Prior to that we were lucky to get 18 months from a bank of mixed new and old. Things improved after that. Unfortunately company policy dictated I use size 8D because this was what we could buy at a resonable price from the wholesalers. These are not the best choice for deep cycling. The banks were typically made up of 3 – 6 of these 8D wired in parallel to power 2500 watt inverters in a rental fleet. We had a dozen charters and I was forever changing batteries. Now I know better and would argue the point with the boss because such a practice was not cost effective. But this happened 20 years ago and the industry has learned a lot since then.