I posted this on another board but I'm still looking for an answer. I had a problem with my '62. It was charging at more than 15 volts all the time. I was able to determine that the cause of the overcharge condition was a 1.5v drop at the regulator compared to the battery. Following help from others on this board I was able to determine that the drop was somewhere inside the car. Most likely the bulkhead connector, ignition switch or connection in the harness where all of the 12v sources are connected. I cleaned the bulkhead connector but the problem still existed. So I decided to isolate the bulkhead connector from the charge circuit by installing a relay under the hood. I used the blue wire from the bulkhead connector to trigger the relay which is fed directly from the starter relay. Charge voltage is now normal. I left the ammeter connected. It now shows a constant slight charge condition all the time. I think it may be because the 12v stuff under the hood, mostly the ignition system, is now upstream from the ammeter. Can anyone verify this? I want to make sure there isn't another problem someplace before I replace the ammeter with a voltmeter.
Excess Charging Volts
- Thread starter Rick62
- Start date
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67Dart273
Well-Known Member
That is absolutely the cause of your ammeter offset. There is no easy answer and still keep the ammeter. Voltage drop in these girls IS a problem, due to several things....
1...Poor design. I used to service HVAC, including electric furnaces, and they typically use the very same type 1/4" wide blade connectors as the Packard connectors in the bulkhead connector on Mopars. The electric furnace elements are typically "nominal" 20A AND THEY FAIL regularly. So now Ma comes along and tries to use them with 35, 45, 55A alternators. Of course they will fail
2....Too small wire, generally, in the harness
3....If you know where to look, you can find what folks call taxi/police/ fleet wiring, which is where the ammeter wiring is modified (dealer? factory) to feed through the firewall with larger wire than the usual bulkhead terminals. This wiring was used on 65A alternators
You have a choice.......
1...mentally subtract the small amount that the relay causes in ammeter offset
2....do the MAD electrical or similar ammeter bypass and add a voltmeter
3.....do your own custom upgrade, run larger wire through the bulkhead to the ammeter and upsize the charging wiring, etc.
WHEN YOU GET DONE you may still have a drop in the ignition switch / switch connector, and you still might need a relay to prevent the drop.
1...Poor design. I used to service HVAC, including electric furnaces, and they typically use the very same type 1/4" wide blade connectors as the Packard connectors in the bulkhead connector on Mopars. The electric furnace elements are typically "nominal" 20A AND THEY FAIL regularly. So now Ma comes along and tries to use them with 35, 45, 55A alternators. Of course they will fail
2....Too small wire, generally, in the harness
3....If you know where to look, you can find what folks call taxi/police/ fleet wiring, which is where the ammeter wiring is modified (dealer? factory) to feed through the firewall with larger wire than the usual bulkhead terminals. This wiring was used on 65A alternators
You have a choice.......
1...mentally subtract the small amount that the relay causes in ammeter offset
2....do the MAD electrical or similar ammeter bypass and add a voltmeter
3.....do your own custom upgrade, run larger wire through the bulkhead to the ammeter and upsize the charging wiring, etc.
WHEN YOU GET DONE you may still have a drop in the ignition switch / switch connector, and you still might need a relay to prevent the drop.
I think the early cars had a better setup for feeding the ammeter. Below is a picture of the bulkhead on my '62. The outboard red and black wires screwed to lugs feed the ammeter. The one in the center is for the power top. I'm thinking it makes sense to eliminate the ammeter anyway and replace it with a voltmeter. What do you think?
67Dart273
Well-Known Member
Yes. Too darn bad Ma didn't stick with it. I don't remember when? about 72 in the Sea Barges Ma started playing with external shunt ammeters. These have their share of problems, AKA some of them are really "numb." My old Ranger, if you turned on the headlights, you had to look intently at the needle to see if it moved.
rc_brooks
Well-Known Member
On mine, I think it always is showing a slight charge. Like you said, the ignition system alone tends to draw a good amount of voltage.
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