If you can get your hands on a DC amp meter with enough capacity, check the drain with the car off. If you find any significant drain, start pulling fuses from the panel one by one until you find the circuit that's doing it, then proceed as may be appropriate for that circuit. If you find there's no significant drain, you've got a battery with at least one bad cell, which is not at all unusual if it's been run flat; replacing the battery should fix it. To double-check the battery, check the specific gravity of the electrolyte in each cell. (Of course, you've already checked the level and replenished with distilled water any cell that's low. I mention that only because I managed to forget that step once.)

__________________
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)