Ammeters vs Voltmeters ???

I think that the ammeters in older machines were often wired with all or nearly all of the electrical load running through the ammeter. I suspect that the Scout ammeter was fine for about 30 amps maximum charge, but 60 or 65 really challenged it.

The Scout didn't burn up, but we worried about that possibility when we saw how hot the ammeter got. We put the battery on the charger overnight rather than continuing to charge with the engine. He kept the Scout for another year with the same ammeter and alternator and it continued to work OK, but he avoided situations where the battery would get discharged a lot.

I recently changed alternators on my 84 F250 because it quit charging and the ammeter needle never moved. With the new alternator, the needle still never moves, but the system appears to be charging--the battery stays up and the electric choke opens. I have studied the wiring diagrams and believe that the factory wiring only measures one of the smaller wires to the alternator rather than the whole output like it was on the Scout.

I think I will add a voltmeter below the dash since I can't seem to figure out why the existing ammeter needle never moves. Maybe the dash ammeter is broken or there is a break in the wiring harness or something? A voltmeter would be able to tell me if there is enough charge in the battery to start the truck, which often sits for a week or more without being used.

My coolant temp gauge quit some time ago and a new sending unit didn't fix the problem. So I already have an accessory temp gauge below the dash. Maybe the Ford gauges are not as durable as the rest of the truck.

Don't get me wrong, I really like the old 84. It has a 460 with an aftermarket AFB carb and has 4 wheel drive. I don't think there is any way I could get that much pulling power for any where near as little money as my old Ford. It has always been very dependable. I won't brag about the gas mileage, but on the other hand, I don't drive it every day.

But old stuff does have its little annoyances and kinks.....

There are several reasons why the switch was made to voltmeters. I think the biggest one is that the high capacity alternators made it impractical to wire ammeters: either you have to have a remote shunt, or else you have to plumb a heavy gauge wire through the instrument panel. Also, it's pretty difficult to tell a one amp charge from a one amp discharge on a 100 amp ammeter. The main reason for using voltmeters is that they are simpler and cheaper in most applications.

Replace your old ammeter with a voltmeter and don't look back. Here's some food for thought on the subject.

Rod

I have had problems starting my Farmall A for awhile and just assumed it was the battery without knowing if I have done anything wrong.

I recently bought the book How to Restore your Farm Tractor by Robert Pripps and discovered what might be my problem.

On page 15 I read about usage of the Ammeter (which before today I thought was merely a light switch). It appears as if I have not been running my tractor right since I never turn on the Ammeter until dark (when I need lights)

Am I correct in my interpretation of the info about Ammeters that normal runnnig means using the ammeter? Would doing so charge the battery and correct my bad starting problems?

Along with your yes or no answer if you could explain simply what the Ammeter does and basically how it does so this electric deficient fool would love to learn about it.

Thanks

Al