Avispa

Just did the headlight relay install mentioned in a few recent posts. These were too good a deal to turn down:

http://www.summitracing.com/parts/via-80238/overview/

After installing them, I noticed the alternator loads up the motor at idle when the lights are switched on. Sometimes the motor will load up and stall from idle. Gauge w/ high beams on and motor of is reading close to -20 when it was only about -12 before. Gotta get the motor to about 1300 RPM to zero the gauge. Just realized it's tapping full power right from the ammeter terminal.

Anyone else notice this?

If anyone's considering upgrading to H1/H4, this chart might help:

http://www.powerstream.com/Wire_Size.htm

The low beams run on 18 ga (110 watts for 2 bulbs, about 9 amps) ok by the chart. High beams are on on 16 ga. Running 4 65 w high beams is about 22 amps, which the chart says is ok.

Frankie the Fink

I run headlight relays on a C1 GENERATOR driven car with no, zero, nada issues.

If you've put in some hi-tech, hi-amperage aftermarket lights they may sucking full current from your system for the first time via the relays....can't say for sure..

dplotkin

Remember the whole idea of the relay setup is to allow more current to the lamps by removing the resistance to current flow posed by the headlamp switch and its wiring. Yet that current has to come from somewhere. And if you have non-stock high draw lamps installed, it is going to put a stock Delcotron to the test, especially if its a small one.

If its stalling the engine-and engine idle adjustment is reasonably correct-then you need to look into that, as that alternator will not last long working that hard. You could have one or more failing diodes, partially shorted stator windings, or an alternator without the capacity to comfortably carry the lights.

Dan

BADBIRDCAGE

When I set up the relays on my 63 I ran an eight gauge, fused, supply line directly from the positive battery terminal to the relays and then ran the standard headlamp harness from the relays to the headlamps themselves. Never had an issue but I was also running a 100 amp, one wire alternator which attached at the positive terminal on the starter along with the positive battery cable.

dplotkin

Wire size is not the problem here, its an overloaded alternator given the OP's description of amp readings.

Dan

toddalin

I've never noticed that the headlights "load up" the alternator enough to drop the idle with the high beams on after my conversion, but then I don't run that much at night.

Avispa

Guys,

Appreciate the comments. There's nothing wrong with the alternator or the wiring. I'm running H5001/H5006 halogen sealed beam replacements. They draw standard current. The reason for the "funny" alternator readings and the alternator loading from the headlights is the HL current draw is now only 2 feet from the alternator instead of going all the way to the solenoid BAT terminal and back again. The whole point of the relay mod is to jack up the voltage at the headlights. Well if you do that, guess what, the current draw increases correspondingly, because the HL bulb resistance didn't change one bit. Ohm's Law and all that. I was laughing at myself for getting all panicked before figuring out that the symptoms are absolutely normal (except maybe for the stalling, but I have carb issues, too).

The point was I thought something was wrong until thinking through what changed electrically before and after the conversion.