What Voltage Should A 12 Volt Battery Read. If your voltmeter is showing a voltage anywhere between 124 and 128 that means your battery is in good shape. With the engine off you should get a reading of 126 volts.
The voltage reading of 124 volts will indicate that the battery is only 75 percent charged. This is called the open-cell or resting voltage of the battery. When the battery is not being charged and not delivering charge to a load this is the rule of thumb.
If the battery is good the reading should actually be higher than 12 volts.
For instance a 6 volt battery will have 3 cells 3 x22 66 volts a 12v battery for a motorcycle for a motorcycle will have 6 cells 6 x22132 volts and so on. A fully charged battery will typically display a voltmeter reading of about 126 to 128 volts. But once the battery is degraded then get it out of the system as it is adding to the load on the alternator which isnt healthy and it will degrade any other battery in the system. There is a very big difference when a car battery drops even a small amount of voltage.
