Re: Charging question

Posted by DavidPackard On 2018/10/28 11:37:40

Roundsy;

If Fifth Avenue agrees that your alternator may be externally excited, then you can lower the 'cut-in' by installing an 'idiot light'. Sounds strange but it works because the bulb current creates a bit more magnetism inside the alternator while it's 'off-line'.

The information you need from Fifth Avenue is;
A.) Is the alternator configured for external excitation?
B.) What is the nominal and maximum current allowed in that circuit?

On your next posting let us know what the supplier's response, plus the voltage ( 6 or 12 ) and polarity ( negative ground or positive ground ) of your car.

I've 'fixed' one of my alternator equipped old cars using this method. You can use an incandescent bulb, or an LED and resistor. Since there is a limited amount of current adjustment with the single incandescent bulb configuration I used the LED & resistor method. I tried several different resistor combinations and settled on a resistance that allowed the 'cut-in' speed of the alternator to be close to the idle speed of the engine. I put one additional switch in the circuit, which allowed me to start the engine and establish a reasonably well idle, and then I would activate the alternator. You could really tell an extra load had just been put on the engine, but that was a low horsepower, low compression ratio original Model A engine.

DP