My question is what on the car can kill a battery, I know that one is a bad alt. but are there any thing else on that can kill it. I have gone through two batterys and I going to get a third one. I put it on the car and put a charger on the last one, It was supporsely new. It lasted for about a day which I dont think because once I started the car I looked at the scan master and it was reading 13.6v and after a minute it when down to 13.0v and it jumps form 12.7 to 13.0v. TOday it was at 11.6v when I just turned on the car and the battery is no good. The first time I put the charged on and the battery was new, it was not good on voltage. I am i just getting bad batterys, from them being on the shelf at the parts store or is there something wrong in the car.