Join Date: Dec 2001
Location: Belleville, Illinois
Thanked 22 Times in 17 Posts
Re: o/t restoring a lead acid battery
One of the causes of failure is that the material slowly flakes off the plates and settles to the bottom. Eventually enough settles that it shorts out the plates. Vigorous shaking will get it stirred up. Then dump it out and fill with fresh acid. That might get it going for a while.
Another cause is bridging as GP'n described. It's a crystaline growth between plates. Sometimes it can be brned off by a very high rate of charge. On a single lead-acid cell that might be five volts or so. That can be dangerous, though, so only do it for a few seconds. That should be enough to burn any whiskers off. Don't let it get hotter than warm to the touch.
In the end, it's probably shot, but you might get a little more use out of it.