What should my voltage gauge read while driving?

Look at the voltmeter while the engine is running. Readings of 14 to 14.5 volts on the gauge when as a good sign. If the voltage reading drops below 12.5 volts, the charging system is not operating properly, and the battery is having to provide current, meaning it will eventually go dead.

What does a voltage gauge do?

This type of gauge tells you how much and in which direction the electricity is flowing. When you turn on the lights and accessories, the voltage regulator senses the lower voltage and kicks in the alternator.

What does the voltmeter gauge indicate?

On the other hand, a voltmeter works like a fuel pressure gauge-but instead of measuring fluid in psi, the voltmeter measures electrical system pressure in volts.