overcharging

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kybatman

kybatman

The Original Bruce Wayne!
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I have read thru several of the overcharging threads and just wanted to put my scenario out here to see if maybe i missed something.


1969 Dart GT 1979 360, powermaster single field alt, mopar performance vr, battery relocated to trunk, Electronic gauges with ampmeter bypass.

Car ran fine for over 2 years and suddenly, battery goes dead, vr pukes out silicone, gauge shows alt at 18+ volts.

replaced all of the above, car will sometimes turn over, start, die, turns over and not restart. replaced Ballast resistor twice as well. other times it starts and runs but still shows 18+ at higher rpm.

Alt grounded to intake with star washers, 8 gauge block to frame ground, 4 gauge ground in trunk to frame.

What am i missing??

Bruce
 
If you were drawing enough current to melt the vr, it is highly likely you fried something else in the circuit. Possibly wiring or the ignition switch. Cooking the ignition switch would cause some of the other issues you are seeing. Depending on how the ampmeter bypass was done, that could have contributed to the melt down. It sounds like the circuit may have been left unfused after the bypass. You should definitely check for fusing before you start driving again.
 
When my dart was over charging it was because of a bad ground on the regulator. I had to get some sand paper sand it to bare metal where it mounts and the problem went away.
 
You are using a electronic VR with a single wire alt, can't do that,
A single wire alt reg varies the voltage and a dual wire alt reg varies the ground
 
3 great suggestions.

Will work on them this weekend, along with a relay perhaps.

Seems that is the direction most chose.

Will have to look at the other VR options as well since it is cheaper to replace than the ALT.

Thank you all.


Bruce
 
I'm pretty sure you can just change the brush holder and make it a duel wire alt. It needs to be insulated from the case and have a connector on it.
 
If it worked for 2 years, then it would seem logical the VR is positive switching regulator, assuming you got the same one.

MP has been selling those electronic VR to go with the 'single field' alternators since at least the mid-80s.
 
Last edited:
kybatman said:
other times it starts and runs but still shows 18+ at higher rpm.
Click to expand...
An alternator that is getting unregulated power to through the field will do that.
kybatman said:
Will have to look at the other VR options as well since it is cheaper to replace than the ALT.
Click to expand...
Did you replace with the same MP regulator? Standard and NAPA have the same thing now.

Mike's right. review his suggestions.
Also make a little diagram of your charging system since its not stock anymore.
Make sure the wire to the field terminal from the regulater hasn't been shorted to another wire.
Finally, take a hand held voltmeter and check the voltage at the regulator input side. That's the wire coming from the ignition 'run', often dark blue or dark blue with white stripe.
^ If it reads around 14 Volts at the same time your dash voltmeter is reading 18 V, or really anything more, then the problem is resistance between the alternator output and the regulator input.
 
kybatman said:
Can this be used rather than the MP VR?

DODGE VOLTAGE REGULATOR KIT, HEAVY DUTY EXTERNAL REGULATOR KIT | eBay
Click to expand...
Nooo! That's for someone bypassing a computer controlled regulation.
And its a negative switching regulator.
It reads the voltage the same as yours, but controls the ground wire. To convert your alternator to work with a negative switching regulator, the ground brush needs to be connected to a second field terminal. Then a return wire from the second field terminal has to be run to the regulator.
 
Mattax said:
Nooo! That's for someone bypassing a computer controlled regulation.
And its a negative switching regulator.
It reads the voltage the same as yours, but controls the ground wire. To convert your alternator to work with a negative switching regulator, the ground brush needs to be connected to a second field terminal. Then a return wire from the second field terminal has to be run to the regulator.
Click to expand...


:)

way above my pay grade and ability..considering going back to OE Style 60amp alternator and replacing the VR again. dont want any more electrical issues and the extra amps are not needed.

Bruce
 
Mattax said:
Probably not. At least not directly. Don't use this to charge a run down battery. But thats never a good idea anyway. There's a pretty recent thread about that if your curious.
Click to expand...

I use a battery tender when parked in the garage.

so far the stuff I have had to replace since the alt swap are: Optima Red Top, MP VR.

and fried the relays that my fans were running on.

:)

Bruce
 
kybatman said:
:)

way above my pay grade and ability..considering going back to OE Style 60amp alternator and replacing the VR again. dont want any more electrical issues and the extra amps are not needed.

Bruce
Click to expand...
Some of it is the terminology.
Field is short for Electro-magnetic field. Electrical current through wire windings makes a magnetic field.
Alternators work by spining that magnetic field and inducing current in another set of wire windings that don't move.

The voltage regulator either stops the current from going into the field, or stops it from coming out.

If you are using an alternator with two field terminals with wires, the second wire goes back to the a voltage regulator like the one you linked to.
If the alternator's second field terminal is grounded, then the voltage regulator controls the power going to the other field terminal.
For that you must use one of the regulators mentioned earlier.
 
Either type of regulation will have the same problem if there is a voltage drop between the alternator output and the regulator.
You'll need to take a voltmeter and measure the voltage at the regulator and/or at the terminal for that wire where it goes on the ballast resistor.
Then you'll know if the problem is the regulator or the wiring.
 
I can check that in the morning.

Going to make up a ground with star washers for the VR off of one of the fasteners as well.

not excited about the thought of sanding anything down to bare metal on a 4 year old paint job.

Bruce
 
kybatman said:
I can check that in the morning.

Going to make up a ground with star washers for the VR off of one of the fasteners as well.

not excited about the thought of sanding anything down to bare metal on a 4 year old paint job.

Bruce
Click to expand...
That sounds good. I hear you on the sanding!
You can check for voltage drop between the regulator body and other ground points like battery negative or the engine block. If there's difference in voltage between two ground where current is flowing then there's resistance.
Do your visual checks first. Definately want to minimize the time the system is running above 15 Volts.
 
You can try running it with the voltage regulator disconnected. If it is still charging, that may indicate you have a wiring issue. Possibly the field wire shorted to positive for a one wire alternator (where one of the field wires of the alternator is tied to alternator case).
 
so,

car does not start with VR unplugged. Returned the MP VR today at Summit. Will start looking for adjustable VR.

Thanks you guys for the input so far.

Bruce
 
I think you have multiple problems. The car should start whether the vr is connected or not. Does it not crank, or not start when it is cranked?
 
cranks but does not start with VR completely disconnected.
 
Do you get voltage on either side of the ballast resistor with the key on?
 
will have to check later..

Thanks Mike, I appreciate the help.

Bruce
 
As Mattax suggested, draw a diagram of how the ampmeter bypass was done if you can. It would make it easier to troubleshoot for us remotely.

The car should start and run with no alternator or regulator until the battery runs down.

You can also try a jumper wire to the battery positive to either side of the ballast resistor. With that hooked up, the car should start and run. That bypasses the ignition switch and most of the wiring. That’s what car thieves do. Just be careful as that is live unfused battery power.
 
anything from the battery + is almost impossible unless i use the connection to the starter witht he battery being in the trunk.

:)
 
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