original ammeter specs

[drypolcher]

Hello, I have done a number of electrical upgrades to my 1949 Willy's 4x4 truck. I have install new wiring, a new generator with 63 amps capacity, and converted to 12 V. I would like to keep my existing ammeter operational. My questions is; what is the original ammeter capacity? That is what, is it rated at? I am sure I need to protect it but I am not sure to what level. Thank you in advance, Tony

one more thing, i have a 12V to 6 V regulator to address a number of other items on my truck.

[gmwillys]

Our resident electrical guru LarrBeard will have information on his page on Hams' 48.

[drypolcher]

Thank you, you are correct about your resident electrical guru. I got all I needed and a lot more, I mean a lot more. I know I should have taken electricity in college.

[gmwillys]

I thought I knew enough, but soon found out I know just enough to be dangerous. College trains you in general theory of how things should work. Folks like LarrBeard are not taught this lesson in any school, they learn from practical, hard earned experience.

[LarrBeard]

For a change, you are in luck!

The ammeter doesn't care a whit about 6-volt, 12-volt or 24-volt; it just cares about which direction the current flows through it. The original ammeter was a +/- 50 amp meter. It never got to +50-amps because the regulator cut off at about 35-amps and if you saw -50-amps, there was a screwdriver shorting something out!

In your 12-volt system, you will have to look just where the ammeter goes because with the original voltage regulator it went in the BAT lead of the regulator to show battery charge/discharge. 12-volt alternators may or may not have a third wire ammeter lead.

But - the 50-amp meter should be OK for a 12-volt system; 12-volt batteries may charge at high rates for a short time, but they generally just perk along at a few amps. With a 100-amp alternator and a dead battery you could peg the meter for a while.

[drypolcher]

Now that I can understand, again thank you. I love this Forum.

[LarrBeard]

Here is a good discussion that considers the ammeter in a 6/12-volt conversion

https://www.yesterdaystractors.com/articles/artint131.htm

We're already negative ground ...

[drypolcher]

The good news keeps on coming, thank you.

[LarrBeard]

The good news keeps on coming, thank you.

In another lifetime I was an engineering manager. I had a guy who was a really knowledgeable subject matter expert. We used to say about Ev; "Don't ask him unless you really want to know all of the answer".

OhMyGawsh - I've become another Ev ....

[gmwillys]

That's OK. Your bank of knowledge helps us all.

Being in the service industry, we tend to figure out what's wrong, rather than figure out why it's right. When it doesn't work we have to go hunting. If it ain't broke, leave it alone before it is.