the 420 wouldnt start yesterday, and I jumped it with my Jeep. Im surprised my jeep battery could start it. anyway, It would run fine, which seems to tell me that the alternator is working fine. However, when i shut the car off, it wouldnt start back up or anything. Fine. Took the battery out to the autoparts store, and they said they tried two diffrent chargers, and the battery would not take any sort of charge whatsoever, either on the large charger or the small charger. I think the battery just went bad. It is a autocraft battery, probably from advance auto parts, but it is relatively new, only ~2 yrs old i would guess. So aside from replacing the battery, is there anything on the car that would cause the battery to fail like that?

and what kind of replacement should i buy, if that is what i need to do?