Ammeter ten amp plus headlight discharge

P

Peyton

Senior Member
At idle with a six volt alternator and later a generator with voltage regulator, headlights consume ten plus amps per ammeter. Bad battery? Car cranks fine. What do you think?
 
Ten amps per ammeter??
10 amps at 6 volts is only 60 watts. 30 watts each headlight, probably less by the time you allow a little for tail light. I wouldn't have been surprised to hear a little more drain than that. I think (and I may very well be wrong) that the Model A in the day used 35 watt globes in the headlights. That would be about 75 watts including tail light. That in turn, equates to 12.5 amps. These ammeters are not high precision instruments so a reading of 10 amps is in the ballpark.
 
What does 10 plus mean ? How much over 10 ?

10-12 amps is fine. Off idle, with a regulator, the ammeter should return to zero or a slight charge after the battery is replenished. With a generator and original type cutout the increased charge rate will constantly show.
 
And watch your gauge & headlights dim when you hit the brakes. Good point for installing LED's to take some of the load off of everything.
 
Thanks everyone. I thought that the ammeter would show a 10 to 12 amp discharge and quickly return to zero.
 
How fast is your idle? I agree with you that an alternator should be able to handle the headlights without discharge at idle >750 rpm, or so.
 
My idle is very slow. The generator is acting just as the alternator. I'm going to reinstall the alternator tomorrow and will see what happens. Will advise. Thanks Steve.
 
My 28 with stock lights draws about 8 amps, and with my powerhouse generator and EVR I can keep the ammeter on zero at 550 RPM.
For anyone using an EVR like the one I and the one James P. makes, that fits inside the generator, the output at the generator stud is regulated to about 7.2 volts, so you have to be sure the cutout contacts close before the regulated voltage is reached. I adjust the cutouts to close at 6.0 volts.
 
I reinstalled the alternator today and cleaned the contacts leading to it. Everything's doing fantastic. When I did the reading showing a discharge with the headlights on, the idle was real low so as not to allow the alternator to produce power. I'm sure that filing the battery and headlight contacts helped also.

Thanks all for your help!

Peyton
 
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