Amp or Volt gauge for a '52

[Rdinatal]

My '52 M37 has wires 8 and 9 out of the regulator. The previous owner had an amp meter but it doesn't work.
What would be best in the cluster?
The easiest to interpret?

New voltmeter and rewire?
Check wires 8 and 9, maybe rewire or new amp meter?

Either way seems just as much work for me.

[John Mc]

Wires 8 & 9 from the regulator are for an amp meter.

If you want a volt meter, just pick up wire 27 from the instrument cluster (it's grounded through the panel).

[Rdinatal]

Wires 8 & 9 from the regulator are for an amp meter.

If you want a volt meter, just pick up wire 27 from the instrument cluster (it's grounded through the panel).

Yes, thanks.

[just me]

A volt meter is a better choice to know what is going on. An ammeter only gives rate. But, because I like to know both level and rate, I have both and mounted the ammeter under the dash in a small panel.

[Rdinatal]

A volt meter is a better choice to know what is going on. An ammeter only gives rate. But, because I like to know both level and rate, I have both and mounted the ammeter under the dash in a small panel.

Thank you. I was leaning towards the volt meter.

I read that with a solid state regulator (which it has) the volt meter is required. The wires might be there in the harness but the regulator has nothing on 8 & 9.
Now, if that's true it explains what is going on.

[ashyers]

This post got me thinking that I should do something about my ammeter that does little more than wiggle.

I picked up a working voltmeter from a friend and removed/insulated wires 8 & 9 from the ammeter. I had a 5 wire spider so I plugged 27 into the rear of the voltmeter and it's up and going, BUT I was curious will having 8 & 9 disconnected cause any unforeseen issues?

On another note I think I may have a regulator issue.
*On our initial test at idle the "new" voltmeter is right at the reference mark in the green area of the scale which matches the value of my DVOM of ~28v. *When I rev the engine the voltage drops to around 25v and the needle on the gauge dithers around quite a bit. I did check the grounds and found no issues there.
*Firing up the high beams and brake lamps has little to no effect.
*After running for some minutes the voltage returns to ~28v and the gauge fluctuations subside.

Any ideas what's going on here? It seems my regulator may be cycling or something???? I've put a ton of miles on the truck and have had no issues with the charging system so maybe adding a gauge was a bad idea !

Thanks

Andy

[Cal_Gary]

I'm on a 12V alternator Andy so I can't help on this one.
Gary

[just me]

I'm on a generator and mechanical regulator. After warmup and the battery has recovered from starting, at idle I'm about 26V. Off idle I'm 28.4V. If I come near stalling the engine I hear the cutout relay cycle and it shows battery voltage.

[ashyers]

just me,
Is your gauge stable? Mine gauge acts like it has no damping at all. I'm wondering if it's the regulator cycling like mad or the gauge is just wonky. I actually show higher voltage at idle than when revved up which is odd.

Andy

[just me]

Rock solid. Until the cutout relay drops. It reacts very quickly as it is an undampened movement. A correctly adjusted mechanical regulator switches at audio rate and the meter can't react to changes that quick and remains stable. It's only when it isn't regulating or there is a voltage level change that you see movement.
Problems with an electronic regulator "usually" manifest in total failure of the charging circuit.
In either system, the generator/alternator and regulator need very good grounds and the same potential at both devices.
I almost always find the problem to be the grounding. I have a shunt meter i use to make sure the grounds are good. (Most of the time, they need a bit of attention.)