Battery Polarity Question

I recently acquired a 1930 Roadster, and when I attempted to remove the battery, I discovered it was connected with the negative terminal to the chassis. When I reinstall it in the spring, should I connect it correctly with the positive terminal to the chassis? Will the generator and starter function as they should? Are there any additional steps, like “shocking” the generator, that I need to take?

Answer:

I recommend reconnecting the battery with a positive (+) ground connection. The starter will work perfectly with either negative or positive connection. If you switch the battery polarity, you’ll need to “shock” the generator to reverse its output polarity. To do this, connect a cable to the ungrounded side’s negative terminal of the battery and briefly touch the cable’s end to the output post of the generator (not the cutout). This action will change the generator’s output polarity.

If you reverse the polarity, you’ll also need to reverse the wires on the back of the ammeter. After starting the engine, check the generator’s output with a voltmeter to ensure it’s producing about 7.2 volts in the negative range at around 1300 rpm engine speed. Other than that, everything else should be fine. – Les Andrews, 1998 Technical Director