Batteries can just go Bad... i had purchased a Interstate Battery
it lasted at about 1 1/2 year's .. had the auto parts test the
car charging system every think was fine, then
the auto parts store told me when i purchased the Battery
this is the best Battery we have , i would not have anything else..

so they pro rated it , took the new Interstate Battery home installed
had a different auto parts check the charging systen every thing was fine

same thing 1 1/2 years later the InterState Battery Died again.

went back to the story where i purchased it the owner said ,
it must be your car, I replied no it is your shitty Batteries...
oh the owner said that is the wrong Battery.. we now have a better battery
some off Brand, I looked at him told him that he could make up this InterState Battery
and i would pay the pro rated if any , and he could keep his World Famous Battery.
an i would never step foot in his store again..
still waiting on this InterState Battery to die been about 1 1/2 years now!