Re: 9N coil

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Posted by Bruce (VA) on April 29, 2018 at 07:15:39 [URL] [DELETE] :

In Reply to: Re: 9N coil posted by Les Leach on April 28, 2018 at 12:17:58:

" At some point I would like eliminate the existing step down resistor and go to a 12V coil. "

As all of us are telling you.........even with a "12 volt ", you still need the oem ballast resistor.

" Also, what is the downside of not having a "stock" resistor in place."

You will melt the coil.

It's in the math, I=E/R.

You need to keep running coil voltage below 4 amps.

You oem ballast resistor is .3 ohms cold, 1.7 ohms hot. The 12v coil is 2.25 ohms. 14.5 volts running. That gets you 3.67 amps.

For a sure start, you need more than 5 amps; the oem configuration gets you 5.7 amps.

The value of the ceramic resistor is unknown, but it's FIXED and is usually around 2 ohms. So, will running current at 3.4 amps is fine, that is also what you get for starting current; it's way too low and will get you a weak spark.

Does that explain why you need the oem ballast resistor?

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