What should the resting voltage of a 12v. car battery be , 2 hours after driving the car 8 miles ?
I think when bought new , the voltage is 12.70 volts.
What resting voltage would be a hint the batt. is about to fail , and should be replaced ?
Or can this only be determined by a cranking/amp test at a dealership or battery seller ?
I realize age and heat are a factor too , but some seem to last years longer than others. I'm also not sure the Brand name assures longer life either. On some batteries you can't even check the electrolite level or top it off.
Is it best just to replace every 4-5 years , no matter what , so you don't have a sudden no-crank failure ?