What Voltage Is A Car Battery Supposed To Be. If you dont have a multimeter to tell you the voltage of your battery you can do a test of your electrical system by starting the car and turning on the headlights. Cars operate on a 12-volt electrical system.
Fully charged automotive batteries should measure at 126 volts or above. 1245-1254 volts means you have a 75 charge 1224-1229 is 50 charged and 1199-1206 volts is 25 charged. When the engine is running this measurement should be 137 to 147 volts.
A no-load voltage below 126 Vdc points to a battery thats either weak or not fully charged.
A fully charged car battery voltage should be 126v or above this is with the engine off. If your multimeter is not autoranging set it to 20V DC. With the engine off you should get a reading of 126 volts. Place the black lead on the negative terminal.
