TorganFM

My guess is the regulator's trash in the alternator. I had the same thing happen to my car. Got a new battery because I thought it was that at first (the car still had the original Honda battery, dated and everything). Then took the car to Autozone to get them to test the alt and sure enough the diodes were shot so the alt was charging and discharging at the same time.

89shithatch

or if you have a batt. tester you can hook up the amp clamp to your batteries and load them down to 12v. than the amperage output should be near that of what your alternator is rated at.