Re: Generator question - negative current

Posted by Fish'n Jim On 2023/11/24 14:25:00

Pretty interesting. Another one of the reasons I don't do pre-war.
My comments/observations;
1.If the "ammeter" was wired "backward", why do you assume all the other connections are 100% correct without a thorough check? (eg;you weren't to sure of the regulator connections)
2. Bulb sockets are another common place for corrosion to take hold and add resistance to the circuits which could be why the circuit breaker trips. It don't always have to be a dead short.
To assume it's tripping low from 'age' and needs to be "upped" is not 'rational' without first checking the amperage draw at which it is tripping.(ie, verify the cause) Like adding a second bullet in roulette because the gun didn't go off. Wasn't a bad bullet... Assume it's working first and find causes for the trip*. Better to replace/swop out a faulty item to check operation, if a good one is available. Don't solve a problem by introducing another. You could fry some wires, devices, etc.
The generator can only output about 30-35A at max. so it appears(to me) you're drawing more than design even with new wiring. These modern AGM batteries are able to withstand more cycle abuse than the wet cell old tar tops. They can consternate the old systems that came with wet cells. You've changed the input power source.
Corrosion will take a few minutes to heat up and then heat itself adds resistance to a circuit.
The headlights are the largest load ex maybe the starter, but that only operates momentary. Cigarette lighters are another large draw and can go bad and draw. It was common for the headlights to dim at idle when the generator output falls off and the 'needle' swing 'discharge' because a starting battery didn't put out on constant draw. That may not happen with a big AGM battery until it gets well drawn down. Plenty of power.
If it was me, I'd re-lamp just to be sure the bulbs and connections are good and sockets are clean/contacting. Do a little DVM ground checking/wire ring outs. But not everyone thinks preventative or systems. Single source reactive is the norm.
6VDC pos grd is one of the least understood items of these old cars. Just look at the posts across the old car sites. We're spoiled by 12VDC neg with alternators, single load circuits, etc.. They just didn't do things that way back then. They mixed branch-wire gauges under large gauge fuses, which is verboten today. They didn't take into consideration them being in operation 80+ years hence.
* - in industry today, simply resetting a breaker without diagnosing the cause of a trip can get one fired at the better shops. Of course, can be much higher amps at play there but there's enough to weld steel here.