Bmw Charging System

[bmwfam123]

When I bought my car the battery would not keep a charge but since the battery was less than a year old bmw gave me a new one for free. That was 2 months ago. I had my car sitting for 2 weeks while I was working on it and now the new battery bmw gave me will not keep a charge. I charged it on 2 amps for several hours and when I unplug the charger the voltage slowly drop. So I had it tested a a local parts store and they said the battery was bad. Now I am thinking something is wrong with my car that caused it to go through 2 bmw brand battery's in less than a year. What could be wrong with my car and how can I test it. My car is a 92 325i. Thank you

[e36surge]

Sounds like a bad ground somewhere.

Have you checked the cables leading to and from your battery? Does your battery show signs of expansion... the sides do the look curved outwards?

Have you checked your alternator? My 318 did that to me once. Turned out the alternator was draining my battery. Yes it drained my battery while I was away for two weeks... all you need is a small draw to drain a battery quickly.

[BImmerN2B]

I second the motion that it was an alternator too. it did that to my mustang before and I had 2 altima batteries.