I have a 95 Jeep Cherokee. It's a three year battery that's only eighteen months old. The posts and connections are very clean. I pulled the alternator and had it tested, it is good. The battery was tested and they found no bad cells and fully charged it for me. I drove the jeep home parked it in the driveway a few days ago, went to start it yesterday and the battery is stone dead again. I can jump it and it'll start, so it's not the starter.

 

well battery's are notorious for acting goofy, because it held a charge and tested good doesn't necessarily mean it is.. Make sure you have good ground with your neg cable..

If you have a meter test your battery now, if not take it in and have it tested.. And I'm curious why I've been reading people take their alternator off to have it tested is this somehow better then me testing it with the motor running??

good luck