you found your problem. i think i heard somewhere that if your alternator doent supply enough power the car willl try to draw electric from the battery. so maybe thats whats happening. i cant remember if that is fact though. and when u think of it what could damage the alternator its pretty much an independent unit i would suppose the only thing affeting the alternator is belt tension, maybe you should check.

 

posted wrong this is in reply to another poster. whoops