Past experience: About the only times I've had a battery behave that way have been when I've been dumb enough not to keep track of the fluid level. The results have always been the same: A battery that's been run down with way-low fluid can be refilled and recharged, but the plates will be damaged enough that it will fail fairly soon afterwards. Moral--Keep the fluid topped up! And of course y'all know it has to be distilled or (at the very least) reverse-osmosis filtered water; pure H2O please, nothing with electrolytes already dissolved in it.

I suspect the problem's worse with constant short runs partly because the battery's always being exposed to a high charge rate, which increases water loss.

Re battery chargers/maintainers: I'm a bit touchy about what units I use, since overcharging is another good way to trash a battery. My personal experience is with the Guest 3-amp Battery Pal unit and their similar 10-amp 3-stage unit, both of which have worked well for occasional overnight boosts as well as for all-winter storage; their circuitry includes a proper float phase for maintenance without risk of overcharging. Both are marine units widely available at ship's stores (West Marine, BoatUS, etc.) I've got the permanent-mount version of the 10-amp installed on our boat (twin gas V8's), where it's managed the dual battery installation without a glitch.

__________________
Craig Bethune

'97 SL500, 40th anniversary edition

'04 Olds Bravada (SWMBO's)
'06 Lexus ES330
'89 560SL (sold)


SL--Anything else is just a Mercedes.
(Kudos to whoever said it first)