Quote:

Quote:

Then run heavy wire from the relay directly to the main alternator pos post or the battery poitive post. This goes on the heavy circuit of the relay. Wire the other side of this relay circuit to the regulator.



I didn't see this post yesterday. Sounds like a quick and dirty way to get my car on the road. Is 12ga wire heavy enough for the positive run?

So, in this case, what would happen when I turn on my headlights? Wouldn't they then be running off the battery? i.e. - the regulator would see this constant 12V from the direct battery connection, so the alternator would not kick out more voltage until the 12V+ from the battery dropped below whatever threshold the regulator needs to turn on. Isn't that not good?

I just want to make sure I understand all this.

Would this also give me the added bonus of headlights not going dim at idle? I've seen references to a fix for that, and never looked into yet ('cause my headlights don't even work at this point, it was a "get to it later" thing).




12ga should be plenty heavy. You might reread the whole thread, I mentioned a relay as well.

So far as headlights/ voltage:

ONCE YOU HAVE the regulator "had tied" to the battery voltage, that is, both a ground and a "sense" (ign) feed WITH NO DROP, then it does not matter what you do with the rest of the car----

the regulator will "try" and maintain it's set voltage, whatever that is, IE about 14-14.5V if it's working correctly.

What SHOULD happend in a good working system--one with no drop in the regulator circuit, no slipping belt, and a good, solid alternator, is that the system should "run" down the road at about 14V +/- V depending on temperature.

When you turn on ANY load, lights, cig lighter, heater, the regulator should IMMEDIATELY try to hold the SYSTEM (battery) voltage steady. The ONLY time this is not so is----

When you have "drop" problems in the regulator circuit as you seem to have

When you have problems with battery cables, and in some cases, the battery itself

When the alternator just "can't keep up" that is, either the alternator is an old 3x A unit, or has a winding or diode problem and just can't put out enough

When the belt begins to slip

NOW NONE OF THE ABOVE has anything to do with how bright the lights are!!! This is because the regulator MAY BE holding the system (battery) voltage at the proper voltage, BUT.....

The lighting circuit is a separate wire, separate connections, separate switch, and all this may ALSO have a "drop" problem, and because the headlights go through the bulkhead connector, they CERTAINLY have at least one more connection subject to corrosion/ looseness/ resistance, and voltage drop.

Using headlight relay(s) may be a good soloution. The wireing on all these old girls was not "all that heavy" even back then, and certainly hasn't improved with age.

You might want to study up on "Ohm's Law" and what we call "I squared R" losses.

If you draw a diagram of a battery--fuse--switch--resistor--lamp--back to battery

The resistor becomes a representation of all ADDITIVE losses in that circuit which are "at least"

The connections at the battery

The connections at the fuseholder and the fuse itself

The connections at the switch and the switch contacts IN the switch itself

The connections at the lamp

All these tiny resistances add up. When the load (size of the lamp) is increased, TWO THINGS may happen

One you get more loss because with a larger load you have more current flow, and this caused more VOLTAGE drop (loss) at each resistance

TWO this larger current causes HEAT which will cause some resistances to go UP in resistance and lose even MORE voltage (drop) so it's a never ending cycle.