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Hello everyone! I'm hoping that you guys can help shed some light on my charging issues because I'm struggling. Car is a 1951 300 with the 327.

Symptoms: at idle the car reads about 6.3-6.4 volts. At approx. 3k RPM the car reads about 6.4-6.5 volts. If I turn the headlights on, the volts start to plummet and it cannot keep up. I keep the car on a battery charger/maintainer designed for 6 volts when I'm not driving it.

Work performed so far: replaced 6v battery, replaced generator with reman and polarized it (at least I believe I did by jumping the bat and arm terminals on the regulator), replaced primary wires from arm to regulator, field to regulator, regulator to battery/starter. I also replaced the regulator itself.

Replacement regulator that was new old stock:



Reman 6 volt 45 amp generator:



Most, if not all, of the existing wiring is crunchy and falling apart, so I am slowly working my way through the whole system replacing with new color coated wire, but this is a tedious process and I haven't completed it yet.

I just want the car to charge correctly and I am stumped. Any advice on where to go from here? This is the first positive ground system I've worked on.

As always, I appreciate everyone's time and input. Thank you in advance.

Basic charging circuit operation is the same whether positive or negative ground. What happens if you momentarily short the generator field wire to ground?

Have a meter connected across the battery to measure generator output just as before and have the car at a fast idle. During the test it would also be a good idea if all accessories and doors were shut so bulbs are off.. If it is still reading around 6.4 volts instead of the wanted voltage of around 7.4v use a short jumper wire with one end connected to ground and MOMENTARILY touch the other end to the FIELD terminal at the regulator. Make sure it is the field terminal you are shorting.

As soon as you make the connection the generator output should immediately jump up to maybe as high as 9 or 10 volts. Only keep the test jumper connected the short amount of time it takes to read the meter. If nothing changes suspect a problem with the generator but do the same test at the Field terminal on the generator itself to rule out a bad connection or broken field wire. If the voltage does jump high then the problem is the regulator. If no change with either test, the generator is suspected.

Another thing is to make sure the generator and regulator are hard connected so they are both referencing the same ground and not being connected thru various pieces of sheet metal. There is a wire connecting the generator case to one of the mounting screws holding the headlight terminal block on the left fender. From that same mounting terminal on the fender there are other wires but the one in particular to check is the wire that goes to the ground terminal or one of the mounting screws on the regulator. That connection needs to be in good condition so the regulator is sensing the same voltage as the generator.

Thank you Howard! I'll try that tonight and post back my results!

Disconnect the field wire then short. Not on the regulator.

Also, as Howard said last, check the grounds. With the car off, ohm between the case of the generator, and the positive battery terminal. Likewise from the case of the regulator to the battery positive terminal. Each reading should be under an ohm or so (consult service manual for more specific guidelines on this test). If it is a high value, your problem is a poor ground connection on the regulator and/or generator.

Though a poor regulator ground I would imagine would cause an overcharging condition, not under.

I know we all try to solve all the problems all the time, but if there's an auto electric shop nearby, they can probably figure it out quicker than back and forth across the internet for these type issues, if one is not well versed. You'd have got it by now.
They can test the gen output and the function of all the components. Reman does mean it's works.
I suspect it's the regulator but just my guess from a far. That's the most likely in any event. It's supposed to react to voltage drop and it's not, so likely at play.
If the wiring was contributing to amp draw, you'd have it all the time without the lights being on.
You can take the cover off and observe the contacts while it's running. Just don't touch anything and shut off before you replace the cover.
Also double check the regulator you got is for your generator and it's wired up correctly. Just being NOS doesn't guarantee it's the right one. There's several variants,even with the same # of terminals and the newer ones are "transisterized" and don't work with these. Plus it's old and maybe inoperative?
Another common one is someone put 12V BATT cables on in place of the thicker 6V. 00 Ga req'd here. 6 v 12 power: Half the volts twice the amps. Wire accordingly.

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If it turns out to be the regulator, any idea where I can pick up a compatible one? The part on Kanter appears to be the same I just installed: Voltage Regulator. I'm to continue trouble shooting it this evening when I get home.

Your NOS one may just have oxidized contacts, a very common thing so disconnect the battery and try cleaning them. However, Napa can order the voltage regulator and I have one that I bought a while back for my 1951 that looks identical to the original Delco-Remy (but without the logo), however, I cannot recall where I bought it.

Be mindful that Packard used both Autolite and Delco-Remy which use different mounting holes. One NOS one you should is the Delco-Remy type but Autolite had one hole on one side and two on the other rather than at the ends.

So I checked continuity from the gen case to the positive side battery and it was 0.0-0.1 so good there. I also checked it between the regulator case and the positive and it was the same result.

I momentarily jumped the field (disconnected from the regulator) to ground and saw zero voltage change.

I also checked continuity between the gen case and the end of the arm wire going to the regulator and I'm good to go there as well.

I reached out to the gentleman I purchased the reman generator through and asked if he has any other ideas, so we'll see what he has to say.

I'm getting to the point where half of me just wants to move to 12v using a system like this: 12v conversion kit. I have been throwing time and money at this 6v problem and I'm ready to pull my hair out.

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The regulator on my 40 110 came from NAPA you might just ask a local auto parts.

I would get it checked before throwing any more money at parts. Find the cause first.

Cheaper to have the generator checked at a shop than to go the 12v route when you figure all the costs involved. And it maintains the originality of the car.

A 6V positive ground alternator is always an option if the generator is junk. But usually cheaper to get the generator fixed.