Charging Problem - Stumped
11-16-2015, 03:02 AM
#1
Charging Problem - Stumped
I posted this on other Mopar sites but so far I haven't found the problem. I do have suggestions I still need to check out. I'm hoping someone here has seen something like this before. I think I'm missing something simple.
My car is a ’62 Plymouth. It has a single field 40 amp alternator with a mechanical voltage regulator. At anything above idle the car always showed a slight charge based on the stock dash gauge. I estimate maybe 5-10 amps. I never considered it a problem. A few months ago I installed an under dash voltmeter. I was surprised to see that anything above idle the voltmeter was pegged at 16v. With the help of folks from various Mopar boards I was able to determine that I had a voltage drop of 2.5v between the battery and the ign terminal on the voltage regulator. The voltage drop was somewhere under the dash. Rather than tearing the dash apart I decided to install a relay under the hood to feed the voltage regulator. The relay is fed from a 10ga wire off the starter relay and triggered by the wire from the bulkhead that used to go directly to the voltage regulator. I started the car and the voltage at the battery is now typically between 14.6 and 14.9 depending on battery condition and about .3v less at the regulator. So far, so good. Except now there’s a new problem. The amp gauge in the dash now shows about 50% charge at anything over idle. I’m guessing this is about 20 amps. When I first start the car it shows full charge for a minute or two then drops to about half but does not go any lower.
I have checked the ground between the battery and the regulator housing. I even tried running a separate 10ga ground wire directly from the battery to the regulator mount. I’ve tried both a mechanical regulator and an electronic regulator. Same problem. Also tried two different batteries. No improvement. And out of desperation I tried a different ignition box. Also no change. I’m stumped. In the past I’ve always been able to find help on one of the Mopar boards. I hope the boards come through again. Thanks!!
My car is a ’62 Plymouth. It has a single field 40 amp alternator with a mechanical voltage regulator. At anything above idle the car always showed a slight charge based on the stock dash gauge. I estimate maybe 5-10 amps. I never considered it a problem. A few months ago I installed an under dash voltmeter. I was surprised to see that anything above idle the voltmeter was pegged at 16v. With the help of folks from various Mopar boards I was able to determine that I had a voltage drop of 2.5v between the battery and the ign terminal on the voltage regulator. The voltage drop was somewhere under the dash. Rather than tearing the dash apart I decided to install a relay under the hood to feed the voltage regulator. The relay is fed from a 10ga wire off the starter relay and triggered by the wire from the bulkhead that used to go directly to the voltage regulator. I started the car and the voltage at the battery is now typically between 14.6 and 14.9 depending on battery condition and about .3v less at the regulator. So far, so good. Except now there’s a new problem. The amp gauge in the dash now shows about 50% charge at anything over idle. I’m guessing this is about 20 amps. When I first start the car it shows full charge for a minute or two then drops to about half but does not go any lower.
I have checked the ground between the battery and the regulator housing. I even tried running a separate 10ga ground wire directly from the battery to the regulator mount. I’ve tried both a mechanical regulator and an electronic regulator. Same problem. Also tried two different batteries. No improvement. And out of desperation I tried a different ignition box. Also no change. I’m stumped. In the past I’ve always been able to find help on one of the Mopar boards. I hope the boards come through again. Thanks!!
11-16-2015, 07:31 AM
#2
ANY load that you take off the starter relay "stud" is on the "wrong end" of the ammeter. So, you need to evaluate what all it is that comes off there, whether fans, pumps, or the ignition system. If you are feeding the ignition "buss" off there, which on that older car is pretty much ignition + the VR, then you have (with a factory system) something along the lines of 10A max load
As long as the wiring and bulkhead connector is in extremely good shape, one way around this is to take the load off the alernator output terminal, electrically if not physically. That is, the black alternator charging line.
What I don't know........not familiar with 62.........is whether they do or don't have the large bulkhead terminals for the ammeter wiring. That is, some of those older cars, for a few years, had very large terminals which were massive compared to most of the 60's or 70's bulkhead in regards to those two conductors.
Once you get the charging voltage correct (seems that it is now) and once you identify any loads off the "wrong" end of the ammeter, then the only thing left is something wrong with the battery.
As long as the wiring and bulkhead connector is in extremely good shape, one way around this is to take the load off the alernator output terminal, electrically if not physically. That is, the black alternator charging line.
What I don't know........not familiar with 62.........is whether they do or don't have the large bulkhead terminals for the ammeter wiring. That is, some of those older cars, for a few years, had very large terminals which were massive compared to most of the 60's or 70's bulkhead in regards to those two conductors.
Once you get the charging voltage correct (seems that it is now) and once you identify any loads off the "wrong" end of the ammeter, then the only thing left is something wrong with the battery.
11-17-2015, 03:09 AM
#3
I don't understand what you mean by "ANY load that you take off the starter relay "stud" is on the "wrong end" of the ammeter". Does that mean things that are connected there have no effect on the ammeter reading? Should I have the feed wire for the relay that I added to the system fed from a different place? On the '62 cars the leads that go through the bulkhead connector to the ammeter are fastened to lugs below the plug in connector with screws. They are not part of the plug in connector that connects everything else. They look pretty substantial. Thanks for your help.
11-17-2015, 08:26 AM
#4
Not exactly. A load properly connected to the alternator side (black wire) of the ammeter will "act" as the system is designed, that is.......
example: headlights
headlights on, engine off, ammeter shows discharge
headlights on, engine running "too slow to charge sufficient" ammeter shows either above same discharge, or maybe a bit more from ignition system load, or moves towards zero as alternator "ramps up."
headlights on, engine running higher RPM, IE "enough" IF the battery is fully charged, the ammeter will now correctly read "zero" as the alternator is now charging and the balance of current has brought the meter to center, IF the battery is "up."
=========================
IF WE WERE to move the headlight tap over to the "red" ammeter lead, that is, the battery side, this is what you would now have:
headlights on, engine off.........headlights are working, but ammeter stays on zero
headlights on, engine running too slow to charge.......same as above, except now OTHER stuff in the car such as ignition has now moved the ammeter over to discharge
as engine speeds up, the ammeter creeps up towards zero
as engine additionally speeds up, and alternator has the ability to balance the system, and let's assume that the battery is now charged, which SHOULD normally result in a zero ammeter reading..........NOW what happens is that the amount of draw of the headlights is now shown as a CHARGE reading on the ammeter.
"The basics" of any auto ammeter: You hook the battery to the starter, as this load is way to big to run through the ammeter.
For everything else, the alternator and all electrical loads are on "one side" of the ammeter, and ONLY the battery is connected to the other.
===============================
And so you could argue, "swell" let's just connect my new relay to the alternator. THIS would be fine, IF the bulkhead connector and it's problems was not there. If it's been upgraded, repaired, or bypassed, then that would be just fine.
This whole problem, to some extent, is derived from the insistence on Ma to 'stay with' so called "full current" ammeters. "She" knew there was a problem, as way back then, an optional 60-65 amp alternator resulted in what has become known as "fleet taxi police" wiring. This in effect is a partial bypass of the bulkhead connector, where ammeter wiring was run through the firewall separately
And as early as 71? 72? The big cars like Fury were "going to" external shunt ammeters. What this does, is to eliminate ALL THAT CURRENT going to and from and through the bulkhead connector. All that is "left" is the feeds into the interior of the car...........the charging current is kept out of the bulkhead connector loop.
I've posted this before. Reading the Mad article CAREFULLY might give some good insight
http://www.madelectrical.com/electri...p-gauges.shtml
Certainly an important part of that article is the simplifed diagram:
Here you can clearly see that NO LOADS are pulled off the battery side of the ammeter (RED) All loads are taken off the BLACK side of the ammeter, and that is exactly where the bulkhead connector "starts the trouble"
There are several terminal in the bulkhead connector that cause trouble:
The big RED and big BLACK ammeter conductors
The ignition "run" feed
And, the headlight "high" and "low" beam feeds
example: headlights
headlights on, engine off, ammeter shows discharge
headlights on, engine running "too slow to charge sufficient" ammeter shows either above same discharge, or maybe a bit more from ignition system load, or moves towards zero as alternator "ramps up."
headlights on, engine running higher RPM, IE "enough" IF the battery is fully charged, the ammeter will now correctly read "zero" as the alternator is now charging and the balance of current has brought the meter to center, IF the battery is "up."
=========================
IF WE WERE to move the headlight tap over to the "red" ammeter lead, that is, the battery side, this is what you would now have:
headlights on, engine off.........headlights are working, but ammeter stays on zero
headlights on, engine running too slow to charge.......same as above, except now OTHER stuff in the car such as ignition has now moved the ammeter over to discharge
as engine speeds up, the ammeter creeps up towards zero
as engine additionally speeds up, and alternator has the ability to balance the system, and let's assume that the battery is now charged, which SHOULD normally result in a zero ammeter reading..........NOW what happens is that the amount of draw of the headlights is now shown as a CHARGE reading on the ammeter.
"The basics" of any auto ammeter: You hook the battery to the starter, as this load is way to big to run through the ammeter.
For everything else, the alternator and all electrical loads are on "one side" of the ammeter, and ONLY the battery is connected to the other.
===============================
And so you could argue, "swell" let's just connect my new relay to the alternator. THIS would be fine, IF the bulkhead connector and it's problems was not there. If it's been upgraded, repaired, or bypassed, then that would be just fine.
This whole problem, to some extent, is derived from the insistence on Ma to 'stay with' so called "full current" ammeters. "She" knew there was a problem, as way back then, an optional 60-65 amp alternator resulted in what has become known as "fleet taxi police" wiring. This in effect is a partial bypass of the bulkhead connector, where ammeter wiring was run through the firewall separately
And as early as 71? 72? The big cars like Fury were "going to" external shunt ammeters. What this does, is to eliminate ALL THAT CURRENT going to and from and through the bulkhead connector. All that is "left" is the feeds into the interior of the car...........the charging current is kept out of the bulkhead connector loop.
I've posted this before. Reading the Mad article CAREFULLY might give some good insight
http://www.madelectrical.com/electri...p-gauges.shtml
Certainly an important part of that article is the simplifed diagram:
Here you can clearly see that NO LOADS are pulled off the battery side of the ammeter (RED) All loads are taken off the BLACK side of the ammeter, and that is exactly where the bulkhead connector "starts the trouble"
There are several terminal in the bulkhead connector that cause trouble:
The big RED and big BLACK ammeter conductors
The ignition "run" feed
And, the headlight "high" and "low" beam feeds
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