Packard Forum Index » Pre-War (1899-1942)

Good idea. Thanks.

The reality is that the vast majority of my driving this car will be in the daytime, But, I do want to be able to drive it at night.

Hopefully, I can make a minor adjustment to the existing thermostatic relay and take care of the issue.

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.

To point one, there is no “assumption”. I have gone back through the wiring several times.

To point two, the headlight sockets are new and all other sockets are corrosion free…this includes, tail lights, brake lights, clock light, speedometer light, high beam indicator light, map light, and gauge light. Those are all of the lights that are tied to the light switch. I previously cleaned all sockets thoroughly.

From there, to suggest I’m not being rational is really out of line. At no point did I say that I was going to make adjustments without first checking the current and following good trouble-shooting practices. You just jumped to that assumption. I did not “assume it’s tripping low from age…”. It is a hypothesis that is that seems consistent with what is happening. That said, I agree that it needs to be verified. Good troubleshooting does include hypothesizing based on observed conditions.

You mention a number of good things to check and verify. Several of which I have already done …check and verify the wiring (including checking all ground connections with a meter), clean all bulb sockets, and install all new bulbs. I do still need to measure the current draw to have a good baseline.

If I have mis-interpreted the tone of your post, I apologize. I just don’t know how else to interpret it as written.

Jim those are good things to check but breakers should only trip because of overcurrent conditions; i.e. shorts. Having corrosion, bad connections, etc. will increase the resistance of the circuit and decrease the current flowing thru it by causing various voltage drops.

Example: let's say a partially corroded wire has 1/10 ohm resistance on a headlight circuit which normally has 10 amps flowing thru it, 6 volts. Roughly speaking, the resistance will cause a voltage drop of 1V. Assuming the current is similar still, it will dissipate 10 watts. Furthermore, the headlight itself will be running on 5V instead of 6V. Realistically, the increased resistance will drop the total current too, but it's hard to calculate because light bulbs have a nonlinear draw.

FYI, light bulbs do not have a linear relationship between voltage and power, or between power and brightness. Higher voltages give disproportionately less power than what would be expected from P = V^2/R since the resistance rises from heat (by a factor of about 10x from room to operating temp); however, higher powers give disproportionately more light, greatly offsetting the earlier effect. In other words, the light efficiency drops much faster than linear when operated below the intended voltage. And likewise, bulbs designed for higher wattage use are more light-efficient than weaker bulbs, even when running at the same voltage and having the same voltage rating. E.g. it takes way more than 25 four-watt night lights to equal one 100-watt incandescent.

A friend, a older long time mechanic working on 1940's thru 1970s, told me if you are having electrical problems that don't make sense "Check each and every ground point to make sure there is no paint, corrosion or anything else interfering with great electrical contact". He was a strong believer that every crimp-on connector should be soldered to the the wire.

Based on photos, your generator and regulator seem to need attention in these areas. Also, use a point file on the regulator's contact points.

GOOD LUCK

Thanks, I’ll do that.