Charging

[KTNC]

I just replaced a battery on my M which is converted to 12V. It starts fine, but I am wondering should the voltage guage by light switch show that it is charging (point to right)when running? It does do that when I turn the lights on. When running with no lights, it remains in the middle... Is this right?

Thanks
 

[Janicholson]

With respect, that is an amp gauge measuring electrical flow, not pressure (voltage). if it is an alternator that is a perfect reading for a charged battery. When the battery is fully charged, the system's voltage regulator allows the charge rate to prevent over charging.
A generator system is less likely to do such a good job, but it is supposed to.
when running at 3/4 throttle it should read 14.2 volts measured across the battery. (a needle type meter is best for this reading) Jim
 

[souNdguy]

does it have a tickle resistor for the genny for when the lamps are on?
 

[John G. Hasler]

If the ammeter swings to the right and stays there when you turn the lights on you have a wiring error.
 

[KTNC]

So it should stay in the middle all the time, lights on or off?
 

[John G. Hasler]

If you turn the lights on with the engine stopped the ammeter needle should swing left, showing that the battery is discharging.
 

[mkirsch]

Is it a VOLT meter or an AMP meter?

What does the face of the gauge say?

Farmall M's came from the factory with an AMP meter, but that could have been changed to a VOLT meter.

An AMP meter would stay in the middle only if the tractor is off. When you turn on the ignition and/or lights with the engine off, the needle should move to the left. When you start the engine, the needle should move to the right.
 

[KTNC]

It's an amp meter, looks like the original. When I turn on the lights with engine off, it goes to the right. Same place it goes when engine running and I turn the lights on. I'm thinking guage is hooked up wrong, maybe when it was converted to 12V..?? BTW should the guage still function the same as when it was on 6V? Battery is brand new...
 

[Owen Aaland]

The gauge will read the same whether it is used with six volts or twelve volts. Most likely when the tractor was switched to twelve volts it was also switched to negative ground instead of the original positive ground. If the wire on the back of the ammeter are not switched when the ground is switched the gauge will read backwards.