QuestionI have a 2000 Hyundai Tiburon and I have replaced the battery 3 times in the last 9 months. The battery shows no signs of wearing down until I go out and it just won't start. I believe the alternator is the problem, but not sure. I was also wondering if the alternator belt could cause this. If the alternator is the problem, what is the best way to remove it. It doesn't look like an extremely easy job.
AnswerIf the alternator belt is so loose that it cannot properly turn the alternator pulley, then it could be causing this problem. Keep in mind, however, that the likelihood of this scenario is very small; in such a case, you should have already noticed some belt squeal or similar occurrence.
I doubt the alternator is the problem, since that would be likely to drain your battery more frequently than every three months (on average). Nonetheless, it's a good idea to check the battery and charging system well.
I think it's most likely that you have excessive parasitic draw (current used by items in the car when it's turned off). What typically happens is that a new battery has enough reserve capacity to withstand the draw, but as it gets to be a few months old, the reserve capacity has diminished enough for the battery to begin having problems if the vehicle is left sit for a significant period of time (such as overnight).
To check your, you'll need to attach an ammeter in-line between the negative battery post and the battery cable terminal while everything in the car is turned off. Your draw should be 50mA or less. Typically 100mA is low enough that no problems occur. Given your description, I'd suspect something along the lines of 200mA to 300mA. If your draw is indeed this large, then you'll need to locate the source and eliminate the draw.
