How many volts should a good battery have?
How many volts should a good battery have? Fully charged automotive batteries should measure at 12.6 volts or above. When the engine is running, this measurement should be 13.7 to 14.7 volts. If you don't 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. What does 13.8V mean on a car battery? When you see 13.8 on your battery with the car running that means the battery is fully charged. In solar power systems with 12v batteries 13.8 is called...