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Headlamps on Ammeter Pegs!

DartGTDan

DartGTDan

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My buddy has a 1963 Dodge 440 with a 383/Auto/AC/PS/PB. He says the Ammeter pegs every time the headlamps are on. I assume it's normal without the headlamps on. The car has a newer alternator and voltage regulator (<500 miles on them). He has ordered another voltage regulator, but will take a few days to get here. I suggested he try swapping a "known good" battery to see if he has a dead or dying cell. He says the battery in the car is one of his "newer" batteries. I told him I'd still swap it with a "known good" battery just to rule it out. Any thoughts?
 
Is it pegging into discharge?

When I had my amp meter hoked up with the old halogens turned on, it would dip pretty far into the discharge side of the amp meter.

Or maybe it's the charge side? Been so long since it's been hooked up.
 
What does the multimeter say? Your chasing your tail if you really have no idea what the voltage is doing. Could be normal and that's what the guage does.
 
It pegs to the Charge side, and I have no idea what the voltages are (headlamps off or headlamps on). He's always busy and has no time to "play". He wants a quick definitive answer without any troubleshooting.
 
Do the headlights have relays? Are they sourced from the batt?

And sorry, the answer requires a troubleshooting on EVERYTHING and not just cars. Even more from the distance
 
Nope, everything is stock. Plans are to put the headlamps on relays, bypass the ammeter (junction block), give it electronic ignition, replace single jug master cylinder with a dual reservoir master, etc.... Unfortunately, time is a precious commodity for him.
 
LED's ftw! Draws less than stock headlamps AND they bolt right in. With Hella lenses.
 
You can try to save anything you want, but still there is something wrong because being correct on a stock setup it should show a bit Discharge or center reading, not Charge... not at least full charge unless something went wrong and shows full charge giving gas to the engine. Pretty much normal get a bit charge giving gas after a long time showing discharge

I'm ponting out to a full fielded alt or damaged batt.

Would check bulkhead connections and ammeter studs, because they could be loosen for long time getting not enough juice from the alt back to the batt, and the read can be somehow correct
 
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The ammeter is showing you what is going from the alternator to the battery. Most of the car electronics is powered from between the alternator and the ammeter. If the it pegs when the light are on my first inclination is the battery is sick. How old it is it? If the battery fails a load test what could be happening is the lights turned on is pulling the battery down and the alternator is going into full gear trying to recharge it because it believes it is discharged when it reality it is just not capable of being loaded hard with the battery and it is collapsing. Take the battery in for a load test or replace it if it is old.

I had a similar head scratcher where I needed to keep the headlights on or it would peg. It turned out the battery I bought has such low impedance while charging that even a battery charger could not move the voltage on it when charging. Because the voltage was low and it could take ALL the current that anything could give it the regulator just went full bore because the voltage was so low.... I ended up charging the battery with my battery charger to get it back to full charged state then the alternator could keep it topped off without going full current.
 
DartGTDan said:
My buddy has a 1963 Dodge 440 with a 383/Auto/AC/PS/PB. He says the Ammeter pegs every time the headlamps are on. I assume it's normal without the headlamps on. The car has a newer alternator and voltage regulator (<500 miles on them). He has ordered another voltage regulator, but will take a few days to get here. I suggested he try swapping a "known good" battery to see if he has a dead or dying cell. He says the battery in the car is one of his "newer" batteries. I told him I'd still swap it with a "known good" battery just to rule it out. Any thoughts?
Click to expand...
That means nothing. I have had "new" batteries with a dead cell right of the shelf. He's gotta test it to be sure and rule it out.
 
Some one has wired the head lights to the wrong side of the ammeter or the head lights are causing the regulator to see a low voltage so ramping the charge up
Check all grounds and connections staring with the voltage the regulator sees and work back
 
Now I've learned the voltage regulator (in his words) "blows" every time he turns the headlamps ON. He has another VR ordered and on the way, but doesn't want to do any troubleshooting until it arrives.

This past week the car has been out and about on several days during the Woodward DreamCruise's festivities here in the Detroit area. It starts, runs and drives perfectly. NO issues at all.
:wtf:
 
sure sounds like a faulty alternator, like it cannot handle the additional load of the headlights. After carefully checking the connections between the alternator and regulator, as well as the grounds, I'd try another alternator.
 
I hate this crap- give me an answer with really no facts; ok, all I can give is suggestions and then it turns out I'm wrong.
 
Even tho I'm retired, my legend lives on at the worksite from the day at work I told a truck driver "I can't fix your engine over the phone" !!
 
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