Current rating for ballast resistor bypass wire

[Dave3066]

Gents

As part of my upgrade to electronic ignition I'm fitting a Flamethrower coil. I need to put in a wire to bypass the ballast resistor wire and wondered if 5A wire was sufficient. Also I've read on a previous thread that the resistive part of the original wire is in the last bit that connects to the coil. Can anyone confirm or refute this as it might save me having to thread a new wire through the bulkhead grommet.

Cheers

Dave

 

[SydneyRoverP6B]

Hello Dave,

Can I please ask what is the Primary resistance of the ignition coil that you intend to install?

I assume that the Flamethrower coil is 12 volt with either a Primary resistance of 0.6 or 0.45 ohms? Coils for use with a ballast resistor typically have a Primary resistance figure of circa 1.5 ohms so I understand it.

With 12 volts applied directly to the coil, with a 0.6 Ohm Primary the current drawn will be 20 Amps, so to allow a safety margin run either a 25 or 30 Amp wire. With a Primary resistance of 0.45 Ohms, current drawn will be just on 27 Amps, so I would look at a minimum of a 30 Amp capacity for your wire.

Ron.

 

[Dave3066]

Ron

Of course.... V=IR, I should've known that!

It says 1.5 ohms on the coil but measures 1.2 with a multimeter so anything above 10 amps should do it.

Thanks for the steer.

Dave