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.

 

Looks good.

 

seems fine now but your old one maybe couldve been drained due to something it maybe coulda just used a charge because 3 years is that old for a battery

 

Thanks. Here's something else.... I just did a reading on my wife's Lexus ('99 RX300, 8 yr old battery, 92K miles) and at rest, it read 12.4v and with the car engine idling, it read 14.2v.

I know that's two totally different vehicles, probably different alternator/charging system design... but 13.7v and 14.2v is a pretty significant gap? Maybe my worry is for nothing?