What Voltage Should A 12v Battery Show. Although a battery is called 12 volt battery its voltage varies from about 12. With the engine off you should get a reading of 126 volts.
As a battery is charged the indicated voltage increases and as discharging occurs the indicated voltage decreases. Battery voltage reacts highly to charging and discharging. 1 With the voltmeter connected to battery and key and engine off record a base voltage reading.
Any voltage above 129 volts is a good indicator that your battery has excessive voltage.
The chart is listed below. When a car drops. Voltage Guide For 12v Batteries. The ideal car battery voltage with the engine running is between 137 and 147V.
