12 v conversion ballast resistor

I run a double resistor system with a hot 12 volt coil. You dont have to but it saves on the points and alternator. The coil resister is IH and the alternator is chrysler. Just have to touch the key and its going strong.

John T

If you replace the 6v coil with a 12v coil, do ya still need the resistor? I seem to remember most all 12v vehicles have a resistor, some are separate and some are built into the wire going to the coil. Do all 12v point type systems, regardless of coil voltage rating, only use 6volts at the coil?

Typical 6 volt coils have a primary resistance of around 1.25 to under 2 ohms while a true 12 volt coil has more like 2.5 to 3.5 ohms primary resistance. Some people call 12 volts coils "Internally Ballasted" and most achieve their higher primary resistance from more wire length or higher resistance wire versus any internal discrete carbon resistor.

Hope this helps

John T

• Hobby farm

As for the coil, I've never paid attention to mine, I'd imagine it could get a little warm. I'd say put a meter on the coils power wires, but unless your meter has a peak hold and can rsolve the frequency, it wont be accurate because its pulsating DC.