What Is The Correct Battery Volt Reading?

OneGuyInCA · November 17, 2010

I tried to start the car this morning and it wouldn't start. It would go tick tick tick tick. I checked the battery with a volt meter and it read less than 11v. I installed a new Duralast battery. Did a reading on the new battery without the engine running and it read 12.8v. Started the car and with the engine running, did a reading again and it came back at 13.7v.

Can someone confirm that these values okay/normal? I'm trying to determine if it's the alternator or that it was truly the old battery that wasn't holding a charge and needed replacement. This is on a 2007 GS350 with about 52K miles and original Lexus battery.

intakerGS · November 18, 2010

With the vehicle not running, the battery voltage should be between 12.5 and 12.8 volts. At engine idle, the voltage should be between 13.6 to 14.3 volts.