Hate to start another thread about my car problems . I recently purchased a second gs300 . These voltages seem very low. The battery was charged yesterday and tested in car today. Voltage goes as high as 13.2 and as low as 11.7 .

 

charging battery would read roughly 13-14v while running. 12v at idle is low. get a volt meter and probe the leads on the battery to get a true reading...never mind the stereo lol

 

13.2-14.5v is acceptable for a normally working alternator under load. If theres some miles on the alternator...then its getting weak. These things are undersized on the GS anyways. If your reading 12.5v under no load, turn on the AC, high beams, WS wipers, and put in gear with parking brake on....bet it dips into the 11s or even the 10s. Not low enough to trip the little battery light in the cluster, but dang sure low enough to cause all kinds of other issues.