My c280 has a problem. The battery doesn't last for a day or so. It seems like some electrical part draining the battery when the car wasn't running. I turned off all the lights but the next day when I try to start the car, the car doesn't have any power. The power door lock doesn't work. The red blinking light on the tape deck didn't even blink. So I assume something was draining the battery when the car was off. I disconnect the battery for couple months because I went out of town and nobody can warm up the car. When I got back I need to jump start the car, turn the ignition switch for couple times and then the car started again. Are there anything that I need to reprogram because I disconnect the battery, and how can I do it? the rear passanger window was broken, and I had it replaced by myself. Do anybody know what causes the battery out for a day? Everytime I jump start the car, the car would start normally. Also I had the battery checked at schucks, they said the battery is good and the charging system is good too. I don't have any idea what would cause this battery doesn't last for a day.

thanks,

Steven.

How old is the battery? If you are sure the battery is good you can use a multimeter and start pulling fuses one by one until you isolate the cause of the drain. As a side note I once had an old BMW that would constantly drain the battery after about 3-4 days of sitting. Turned out the trunk light was staying on.

__________________
Ali Al-Chalabi

2001 CLK55
1999 Dodge Ram 2500 Cummins Diesel
2002 Harley-Davidson Fatboy
Merlin Extralight w/ Campy Record

You need a new battery, replace it pronto!!

Hi there,
Do you think there is a possibility you could have reversed the jumper cables for an instant when you jumped the car? If you did, it's quite possible you shorted out some diodes in the alternator. They would cause the battery to discharge very quickly. Try feeling the alternator after the engine has been off for an hour or so to see if it feels warm. If it is, that's your problem. There are other parts that can be easily destroyed by careless "jumping", but the alternator is the most obvious and will drain the battery quickly.
Good luck,
Richard Wooldridge
'82 300D/4.3LV6