2010 Toyota Corolla Q&A
2010 Toyota Corolla Question: What should the battery voltage be when car is running?
CHARGING VOLTAGE SHOULD BE ABOVE 13.2 - FOURPOINTSAUTO
14.6 would be high normal, 13.5v would be acceptable battery charging voltage. Check voltage across the battery terminals, leave the black ground wire at the battery post (-) move the red volt lead to the large wire post at the alternator if the voltage is different you have a voltage drop (youtube voltage drop there is a good video there). At rest engine off battery voltage should be 12.6 volts at rest if battery is charged and good. - patrick mannion
above 12.75 - MB Center
Anything below 13.5 volts with loads like lights, A/C and wipers on. No less than 13.5 volts. - PARTS GUY