R.I.P

 

When I hit five years for a battery, if I see so much as a slight hiccup, it is gone to be replaced pronto. I don't want to play games with that.

 

The problem is that I don't see a "slight hiccup" because the battery is on a maintenance charger. The charger takes care of the small "drains" from the electronics that never shut off, but, once off the charger, the battery will start the car after 10 minutes, but after an hour the weakness becomes apparent and will no longer start the engine. :-(

 

Read the voltage across the battery terminal with the car at idle and warmed up. It must be above 13.5 volts, or the alternator is not charging the battery.

 

If it is fine after maintaining charger but dies in the car, I also see an issue with parasitic drain and or alternator charging issue.