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

1st off I'd like to say thank you to everyone who helped out with my lighting questions a few days ago.

I've had my 1941 One-Twenty only a few weeks now, and decided I needed a battery tender for it.

Last night when I went to connect the battery tender, I discovered that the battery had been installed negative ground, instead of positive ground. The attached picture shows the cable coming from positive terminal on the battery, connected directly to the starter solenoid.

My questions is; Can I simply reinstall the battery in the correct positive ground orientation, and re-polarize the generator? Is there anything I should look out for?

Thanks in advance,
Chad

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A common problem, many folks who grew up in the 12-volt era don't realize that the majority of 6-volt cars were positive ground, Packard, Ford, Chrysler and many GM makes at various times. Assuming no other changes were made all you should need to do is reverse the battery terminals and repolarize the generator. But check the action of the ammeter; if it now reads "backwards" (needle to the (-) when charging), you may have to reverse the leads on the back of it; if the polarity change was deliberate someone may have made a change there to correspond to the battery polarity change.

If your car has any solid state devices added like a solid state radio vibrator or perhaps electronic ignition, they ARE generally polarity sensitive.

Owen,

Thank you for the help.

I have been trying to remember how the ammeter was behaving when I drove it this past weekend, but cannot.

This is my first vehicle with a generator.

Is the easiest way to test this by turning on the ignition, and then the headlights, without starting the car? I assume it should show charging, if just the battery is installed reversed. If it shows discharging, then something else has been rewired, possibly the ammeter wires.

I'll check it out this afternoon when I get home from work and see if it reads backwards.

I read through this Form Post and it helped explain some too.

I know for sure that wiring work has been done on the vehicle, as there are plastic wire looms, and zip ties holding wire bundles together, plus crimp on bullet connectors...I'm trying to work through things as needed, and not drive myself crazy.

Chad

Is the easiest way to test this by turning on the ignition, and then the headlights, without starting the car? I assume it should show charging, if just the battery is installed reversed. If it shows discharging, then something else has been rewired, possibly the ammeter wires

Yes, but no need to turn on the ignition, just the headlights will draw enough current to determine what you need to know.

Don't forget to polarize the generator after you've reversed the battery but before you start the engine.

Owen,

I changed the battery polarity, and repolarized the generator, following a procedure posted on another post on these forums. The ammeter read correctly when I turned the key on, and turned on the headlights. Took it for a test drive and all seemed well.

Thanks for your help,
Chad

Be aware that voltage regulators are specific for either Pos or Neg ground. Usually stamped on the regulator. It has to do with the contact points in the voltage relay.

Jim