How many volts is a battery supposed to test when the vehicle is running?

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 voltage would you expect to see at the battery with the engine running and no electrical loads switched on?

The no load (everything off) battery post voltage should be at least 12.6 volts and as high as 13.8 volts.

What is the normal voltage for a car alternator?

A good alternator should put out between **13.5-14.5 volts. Stress test the alternator – Place a load on the alternator by turning on the headlights, the radio and the air conditioning. The voltage should remain high with these circuits on.

Is 13.5 volts a good battery?

This voltage range means the battery is in good condition for starting the vehicle. If the measured reading is less than 12.2 volts, the battery’s resting voltage is weak, which means it most likely needs to be charged or replaced. With the motor running, the multimeter rating should stay in the 14 to 14.5 volt range.

Is 13.5 volts good for car battery?

If the voltage stays about a volt higher than resting voltage (e.g., about 13.5V), then the car’s charging system is functioning. But if the voltage drops (or increases) dramatically at any point, there’s a problem in the alternator or the voltage regulator.

Is 12.9 volts good for car battery?

Check the reading. A fully charged battery will typically display a voltmeter reading of about 12.6 to 12.8 volts. If your voltmeter is showing a voltage anywhere between 12.4 and 12.8, that means your battery is in good shape. Any voltage above 12.9 volts is a good indicator that your battery has excessive voltage.