I hadn't thought about that.I just skimmed through a bunch on Ebay and didn't see one that starts at less than 8 volts.This could be a non-starter due to lack of parts!

  

12 volt could be used but.... most I have seen do not have good if any markings below about 8 volts. If you can find a gauge that is marked low enough it will work fine. Remember marking scale will need to be precise enough so you can tell the difference between 6 volt not charging and approx 7-7.5 volts when charging. Like I say finding one that reads that low will be the challenge. I know Classic can build you one but imagine that would be $$$ Mike

1956 Fairlane Victoria (ORREO)

 

Overlooking Beautiful Rimrock AZ

Mike! Any voltmeter can be used then? 6 or 12 makes no difference?

  

Mark, Wire from ign switch should go to the Negative ( -) side of the gauge. Mike

1956 Fairlane Victoria (ORREO)

 

Overlooking Beautiful Rimrock AZ

My buddy wants to put a voltmeter in his 55 which is 6 volt positive ground.Do I use a any regular voltmeter?Do I wire the wire from the ignition switch to the + or - side of the gauge?