amp gauge and one wire alternator

[65truckowner]

If I read right in the search I performed it says for a one wire alternator and my original amp gauge to work hook the positive side of the gauge to the positive battery cable then the other side of the gauge to the mounting bolt at the alternator. Is this not a direct short? The hot wire from the battery goes through the amp gauge then to the grounded wire at the alternator. This does not seem right to me. What am I doing wrong.

[tincan1966]

I would assume the article meant the mounting bolt for the BATT wire at the alternator, but would agree that is poor wording.

[65truckowner]

So the positive wire goes to the positive battery cable and the other wire coming from the other side of the gauge goes to the back of the alternator where the wire connects to the battery cable to charge the battery?

[brokenspoke]

sounds like a fire waiting to happen.....I would suggest that you check out ( madelectrical ) for some good reading on one wire alternators

[luvbowties]

Originally Posted by 65truckowner

So the positive wire goes to the positive battery cable and the other wire coming from the other side of the gauge goes to the back of the alternator where the wire connects to the battery cable to charge the battery?

Sounds like those 2 points are identical, electrically, meaning no movement of ammeter needle. An ammeter needs to be connected in SERIES, somehow, between alternator output and the battery positive. But, I'd be scared to wire the original ammeter this way, as ALL the amps from alternator would be passing thru the ammeter: very hot & burning out gauges and wiring.

I never understood how they did it from the factory...they must've used resistors in two parallel paths from alternator output to battery positive, allowing most of the amps to go from alternator to battery thru the path with a small resistor; and only a representative few amps to flow thru the other alternator-to-battery parallel path (having the bigger resistor) which allowed much smaller amps to flow thru the ammeter--and just a tiny amount of heat due to small amp-flow.

A VOLTMETER WOULD HAVE--AND STILL DOES, IMHO--MADE MORE SENSE. WHY?...An alternator, by design, charges even while idling; so the left (or "minus") half of the ammeter would be unused. When revving the engine, esp. when lights or other loads are being supplied, the alternator puts out higher voltage; hence a good place for a volt meter...and the voltmeter uses just tiny wires--like 16-gauge or smaller--to sense how much the voltage is; whereas a true ammeter would take two much bigger gauge wires--like 10-gauge--one running all the way from back of alternator to ammeter, and a 2nd all way from ammeter back to the positive battery terminal.

I believe I did not answer your question! Yet, hopefully this will keep you from attempting full alternator output thru your factory ammeter--and burning it out. [May even intuitively suggest how to wire it up safely and effectively using 2 alter-to-batt wires with each having properly-sized resistors to split, unevenly, the amps going thru each, with the much smaller amps going thru the ammeter.] May even tempt you to leave your ammeter non-functional and add a system-revealing voltmeter!

Good luck, and enjoy all these wonderful opportunities to THINK, that our old buggies offer us. Spending $15 and fixing an issue offers much greater challenge and satisfaction than throwing that same $15 towards a "bottle"--and you feel so much better the next morning!
Sam

[65truckowner]

I never did like an amp gauge anyway. I am just going to leave it unhooked and not mess with it. Thanks for all the information.

[Sharps40]

Covered in this forum - I think this is what ya want - for both full load and differential c10 amp meters and with one wire alternators.

http://67-72chevytrucks.com/vboard/s...d.php?t=324105