Hello everyone,
It was hard to start the car this morning and battery shows 12.97 v with the engine off on auto zone battery checking machine and also showing “Bad battery “message on top , and it shows 14.2 V with engine running . What seems to be the problem ?
FYI , new alternator.
the battery voltage probably sags too low during cranking.
This is caused by high internal resistance.
How old is the battery?
3 years
What’s the warranty on your battery? If it is under warranty, try to get a replacement under warranty.
CCA of your battery is low.
Any battery voltage showing 12.7v with the engine off and 14.2 with the engine idling is good to me. I think the Autozone battery tester is probably calibrated to sell you a new battery and not to present you with reality.
What do you think it was hard to start the car then ?
See Mountain Man Joe's excellent explanation.
I think we can agree on one thing , the 12 v go down when you try to crank the engine, because the cold crank Amp is low due to a bad cell , so the autozone reader was right, having 12 v on a reading dose not guarantee a CCA to start the engine in the morning.all you guys was trying to say the same thing but you were using a different method of explaining .Thank you