Well recently I've been trying to charge a number of old maintenance free (MB specific) batteries that have been sitting is cars (terminals connected) for sometimes years. These things can be up to $300ea so there was a fairly high desire to resurrect at least a few. But no dice...
I have two full size chargers and each one refused to flow any current through the batteries, even after many hours on the high or low current settings. I wondered if the plates were getting coated with debris and this was eventually shorting them out internally. I thought I might be able to save a battery by draining the electrolyte, flushing and refilling with fresh acid to regain an electrical circuit. However the maintenance free ones prevent this type of procedure.
In the end I called Battery World and asked why I was having so much trouble. They stated that after a while the acid eats away at the plates, if they're always in a state of discharge. This can sometimes be evident by the case expanding or bulging. Basically there's nothing that can be done once a battery reaches this point and you have to buy a new one. However I was told that regular charging at least ONCE A MONTH can ensure the battery lasts more than a couple of years. If you get more than 5 years out of a battery you're doing very well.
I also tried charging the battery for my Buick, which I just discovered was 13 years old (it still looked good)! I was using a trickle charger on that one for a while, but it seemed to have a dead cell. Attempts at proper charging for many hours had all cells but one bubbling slightly and warm to touch around the outside. Frustrated, that battery was also sent off to be 'recycled'.
I have two full size chargers and each one refused to flow any current through the batteries, even after many hours on the high or low current settings. I wondered if the plates were getting coated with debris and this was eventually shorting them out internally. I thought I might be able to save a battery by draining the electrolyte, flushing and refilling with fresh acid to regain an electrical circuit. However the maintenance free ones prevent this type of procedure.
In the end I called Battery World and asked why I was having so much trouble. They stated that after a while the acid eats away at the plates, if they're always in a state of discharge. This can sometimes be evident by the case expanding or bulging. Basically there's nothing that can be done once a battery reaches this point and you have to buy a new one. However I was told that regular charging at least ONCE A MONTH can ensure the battery lasts more than a couple of years. If you get more than 5 years out of a battery you're doing very well.
I also tried charging the battery for my Buick, which I just discovered was 13 years old (it still looked good)! I was using a trickle charger on that one for a while, but it seemed to have a dead cell. Attempts at proper charging for many hours had all cells but one bubbling slightly and warm to touch around the outside. Frustrated, that battery was also sent off to be 'recycled'.