Volt meter question

Stupid question but should an accessory volt meter be always on showing 12v?

Thanks!

 

No, should be on when the ign key is on, showing battery voltage about 14 volts.

 

As told above, only when the ignition switch is on. 12 volts, or slightly higher when engine is not running, 14 or so when it is will confirm generator/alternator is doing it's job.

 

If it's reading 12v or below you're "Running on your battery" and gonna get stranded.

 

Ok thanks guys!

 

With everything working normally and an accurate volt meter:

Turn on the key, battery should show between 12 and 13 volts ( a fully charged 12v battery is actually 13.2)

Turn the starter, and the starter can draw the voltage down to 10 or so depending how cold it is, etc

Engine starts, voltage to at least 13.2

Rev the engine a bit, should go to 14.5

 

Disconnect the battery cable, ans see what does it show. It could be a meter out of calibration.