Overcharging 68Dart...need some short fused help (pun intended:)

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capnswanny

capnswanny

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Hey folks, I could really use some help finding the reason my 1968 Dart is overcharging.
I have 24 hours to solve this so my son can drive the car he inherited from his grandpa in a Senior graduation parade tomorrow. I have spent the past week pouring over the forum and learning/digesting the information about overcharging. I have done all I can find to fix this but I’m still overcharging. I’m definitely missing something, and don't know what it is :-/

We have a 1968 Dart 270 with a 318. I have added an electric fan and stereo…but that’s about it. Here’s my problem…sorry for the diatribe I just want to provide as much info as possible.

We took the Dart for its longest drive 2 weeks ago (about 10 miles) and found that the Ammeter was at discharge. Got home and battery was at about 11v. I replaced the original 1968 VR with a new one from NAPA. Now it charges! But I noticed smoke wisping from the back of the VR when the car was started up at fast idle. Put a meter on the battery and it was indicating 16VDC at idle.
I purchased a VR106 thinking it was just an undersized reg for the added electrical load. I ran a ground from the regulator to the master cylinder and fired her up. Again, smoke wisping from the underside of the VR. I read a voltage drop from the battery to the regulator as I’d learned here and it was at 1.5VDC! Nowhere near the 0.2 to 0.3VDC drop I should have…Bad!!
After digesting more of the great info on this site I tried tracing the voltage losses through the path but was unable to pinpoint to a single source, I had loss through bulkhead, ignition switch, bulkhead, etc...
So, I added a fused 30A relay to send voltage directly from battery to VR using the Blu/Wht wire as signal for the relay as I’d read in some of the posts. I also added a parallel 14GA wire from the output post on the alternator directly to the Ammeter. I bypassed the Ammeter by connecting all wires to one terminal. I ran a ground direct from battery (-) to the VR Ground plane (chassis). I replaced all the terminals at VR, Alt, and Ballast. I also added a missing ground from the engine to the master cylinder bolt (cleaned), Installed a rebuilt alternator and a new Interstate Battery (fully charged) and tried it again.
As soon as we started the engine tonight, smoke started wisping from under the VR again, but it seemed to regulate the voltage. ~13VDC at idle as read on the battery, and ~14.8 at 2000 RPM.
We let it warm up and went for a drive….after about a minute of driving the volt meter was sitting at 17VDC. Pulled back into the garage and took the following voltage readings with my new Fluke DMM:
Batt (+) to (-) @Idle: 12.6VDC
Batt (+) to (-) @2000 RPM: 17VDC and climbing
Batt (+) to VR @ Idle: 0.07VDC
Batt (-) to VR chassis @ Idle: 0.008VDC
Output at Alternator to Bat (-) @Idle: -0.5VDC (DMM (+) on Battery, (-) on Alternator)
Output at Alternator to Bat (-) @2000RPM: -2.3VDC (DMM (+) on Battery, (-) on Alternator)

I’m not sure what I have missed. I have a another new Standard VR106 in a box in case the one in the car was damaged by the original voltage drop. I wanted to tap you smart folks before I threw more $$ at the problem.

Thanks in advance for any help you can lend.
IMG_1677.jpg
IMG_1678.jpg
 
Fyi, the voltage regulator does not carry any load from the electrical system. It simply veries the voltage to the field of the alternator.

if you need to drive the car for a short time you could disconnect the field wire from the alternator, and tape it up so it can not short. You will be running on battery alone but with a fully charged battery you have an hour or so, less if the fan is running.

Is there anything on the fender under the VR that might be touching the back side of the VR?
 
BTW If you still have the OEM mechanical fan maybe now is a good time to put it back on.
 
What is the white wire attached to the red on the VR?
 
Are you sure you have the VR wired correctly? The is a input and an output.

Input should come from a switched source, like the ignition switch. The output should go directly to the field terminal of the alternator. No other load should be attached to the field side.

This is the basic 1 field wire alternator setup.

The "field -" may or may not be internal to the alternator

moparpre70.gif
 
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Thanks for the reply!
I can't put the mechanical fan on as I had to replace the radiator when it sprung a leak....it was a one step forward, two step back kind of day! The new rad is too thick to fit the fan blades so I went electric.
There's nothing on the back side of the VR bolts but air and tire.
The white wire on the VR feeds ignition (externally fused) to the fan relay with a ground coming from the temperature sender to engage. I pulled the relay when it was overcharging and it didn't change anything. But thanks for making me think on this, not the best setup...I'll ditch that and send it to the fuse box in case it's adding load.
I appreciate your feedback...Thanks!
 
Is your ignition system electronic or still points. If you changed to electronic maybe you have the incorrect voltage regulator ( points vs electronic). Get a 2 field alternator and a electronic voltage regulator say 72 or so . Find the wiring directions online on how to convert from a 1 field alternator to a 2 field alternator and see what happens. While you are at it replace the ballast resistor with a fresh one made for electronic ignition mopars like a 72 or. so.

I always upgrade all my cars to the 2 field alternator system. it seems to be much more reliable than the 1 field rarley pop a ballast resistor or have an ignition module go out. and you might as well upgrade to electronic ignition while you are at it, if you have not done so. Order the kit from summit and ditch the points.

Ditch all that relay crap you should not needed it, If you are ordering the 2 field version from napa, ask for the a/c version it will have an extra pully but will have higher amperage, then when you have more time buy a powermaster alternator

it is also possible with all the playing around you have been doing the battery needs to charge it self so it reads higher does it settle down after a minute or so if you hold at 2,000 rpm. Does the vr stop smoking?

The ignition and charging system is quite simple so don't overthink it.
 
Early a body said:
Is your ignition system electronic or still points. If you changed to electronic maybe you have the incorrect voltage regulator ( points vs electronic). Get a 2 field alternator and a electronic voltage regulator say 72 or so . Find the wiring directions online on how to convert from a 1 field alternator to a 2 field alternator and see what happens. While you are at it replace the ballast resistor with a fresh one made for electronic ignition mopars like a 72 or. so.

I always upgrade all my cars to the 2 field alternator system. it seems to be much more reliable than the 1 field rarley pop a ballast resistor or have an ignition module go out. and you might as well upgrade to electronic ignition while you are at it, if you have not done so. Order the kit from summit and ditch the points.

Ditch all that relay crap you should not needed it, If you are ordering the 2 field version from napa, ask for the a/c version it will have an extra pully but will have higher amperage, then when you have more time buy a powermaster alternator

it is also possible with all the playing around you have been doing the battery needs to charge it self so it reads higher does it settle down after a minute or so if you hold at 2,000 rpm. Does the vr stop smoking?

The ignition and charging system is quite simple so don't overthink it.
Click to expand...
 
I'm still running a point distributor, and the VR stops smoking after the first two minutes, low or high RPM...not sure why it's smoking though. I suspect excess current, but not sure what would cause that....
Electronic ignition is in the future plans, but I'm just trying to make this system work for now.
Thanks again for your help man, much appreciated!
Corey
 
Dana67Dart said:
Are you sure you have the VR wired correctly? The is a input and an output.

Input should come from a switched source, like the ignition switch. The output should go directly to the field terminal of the alternator. No other load should be attached to the field side.

This is the basic 1 field wire alternator setup.

The "field -" may or may not be internal to the alternator

View attachment 1715740520
Click to expand...

I pulled all the tape and loom, the field wire from the alternator to the VR is unmolested and un-shorted. Thanks for the tip...another place I hadn't physically looked!
-Corey
 
capnswanny said:
There's nothing on the back side of the VR bolts but air and tire
Click to expand...
I was referring to the back of the VR itself. Most have 2 to 3 wire wound resisters and if the right one gets shorted it might cause an issue don't know if it would cause your issue.

Maybe your VR is wired backwards.

The screw lug goes to the field terminal on the alternator (green in 67) . The slip on terminal goes to switched (blue in 67 - ignition)
 
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capnswanny said:
I'm still running a point distributor
Click to expand...
Points have worked fine for 100 years.

capnswanny said:
and the VR stops smoking after the first two minutes, low or high RPM...not sure why it's smoking though. I suspect excess current, but not sure what would cause that
Click to expand...
The only thing that would cause excess current draw through the VR is a shorted field windings in the alternator, a short in the field wire from the VR to the alternator, or an electrical, short behind the VR ir st it's terminals.
capnswanny said:
Electronic ignition is in the future plans, but I'm just trying to make this system work for now
Click to expand...
Not needed, points work fine, are simple and easily repaired.

Regarding changing to a square back alternator and a 2 field wire electronic VR, again not needed,

I know you spent a bunch on a super dooper aluminum rad and electric fan but if you go back to a copper brass and mechanical fan 1/2 of your issues will be gone.
 
Dana67Dart said:
I was referring to the back of the VR itself. Most have 2 to 3 wire wound resisters and if the right one gets shorted it might cause an issue don't know if it would cause your issue.

Maybe your VR is wired backwards.

The screw lug goes to the field terminal on the alternator (green in 67) . The slip on terminal goes to switched (blue in 67 - ignition)
Click to expand...

Screw lug is a new direct wire to the field terminal on the alternator, the slip on terminal is now through a relay direct to the battery terminal because I saw a voltage drop from the battery terminal to the slip on connection of 1.5VDC.

I'll double check that the coils on the bottom of the VR aren't touching anything,

Thanks!
 
Dana67Dart said:
Points have worked fine for 100 years.


The only thing that would cause excess current draw through the VR is a shorted field windings in the alternator, a short in the field wire from the VR to the alternator, or an electrical, short behind the VR ir st it's terminals.

Not needed, points work fine, are simple and easily repaired.

Regarding changing to a square back alternator and a 2 field wire electronic VR, again not needed,

I know you spent a bunch on a super dooper aluminum rad and electric fan but if you go back to a copper brass and mechanical fan 1/2 of your issues will be gone.
Click to expand...

I'll double-triple check all my wiring to the VR, and it's mounting.
I'm going to replace the wire and fusable link between the bypassed ammeter and starter solenoid and see if it gets me anywhere.

Do you think that the smoke I've released from the VR thus far warrants installing the new one I have at this point? Could that have been damaged by the previous voltage drop enough to prevent it from functioning properly?

Thanks again for your help!
 
Dana67Dart said:
Points have worked fine for 100 years.......

......Not needed, points work fine, are simple and easily repaired.......
Click to expand...

Indeed. I like points so much, I'm converting a single point slant distributor to a dual point. They just work.
 
Let's back up here and start over somewhat

1...Smoke is NEVER good
2....You may either have a wire crossed or somehow hooked into the VR / field circuit, OR the alternator field may be partially shorted and drawing too much current

If you do not have such, wander over to MyMopar and (free) download yourself a factory service manual. In section8 under alternator is a procedure to measure field current draw of the alternator. We need to know what that is.

Do that BEFORE you install another VR

3...Next I would try wiring in the new VR "direct" temporarily, that is, wire a new temporary wire direct from the VR F to the alternator field, and "temp" a wire direct from the VR IGN to the battery. Disconnect the VR IGN from battery when not running.

Test the output and voltage/ etc as to battery voltage, and alternator drop between alternator output and the battery +

Make CERTAIN the VR is grounded.

4...Finally if this all works out, no smoke, proper system voltage, etc, you can start backtracking and implementing te thing back into the system, carefully checking wiring each step of the way
 
67Dart273 said:
Let's back up here and start over somewhat

1...Smoke is NEVER good
2....You may either have a wire crossed or somehow hooked into the VR / field circuit, OR the alternator field may be partially shorted and drawing too much current

If you do not have such, wander over to MyMopar and (free) download yourself a factory service manual. In section8 under alternator is a procedure to measure field current draw of the alternator. We need to know what that is.

Do that BEFORE you install another VR

3...Next I would try wiring in the new VR "direct" temporarily, that is, wire a new temporary wire direct from the VR F to the alternator field, and "temp" a wire direct from the VR IGN to the battery. Disconnect the VR IGN from battery when not running.

Test the output and voltage/ etc as to battery voltage, and alternator drop between alternator output and the battery +

Make CERTAIN the VR is grounded.

4...Finally if this all works out, no smoke, proper system voltage, etc, you can start backtracking and implementing te thing back into the system, carefully checking wiring each step of the way
Click to expand...

Great troubleshooting advice, thanks!
I'm with you on the smoke....always a bad sign!
I checked my FSM, Section 8. I can do the Field Circuit Resistance test, but I don't have an Ammeter capable of the Amp draw or loading for the other tests.
I'll definitely do #3, externally wiring in the VR, isolated from the system is a great idea!
Thanks!!
 
Don't you have a multimeter with a 10A or 20A scale?
 
No you are reading the wrong section. I'm talking about the amp or current draw of the field or the rotor. When you take the field and connect direct to a battery, and monitor the current, and gently turn the pulley to rotate the brushes, it should only draw 4-6A or so depending on the alternator. "Back in the back" in the specifications it should show allowable amp draw

Your Fluke should work fine.

EDIT '68 book says

2.38 to 2.75 Maximum amper

I'm pretty sure later/ larger output ones can be more

'74 manual shows up to 3.4A

I did not find the procedure in the 68 book but 72 it is page 8-29, "Bench tests", "field coil draw"
 
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Dana67Dart said:
the voltage regulator does not carry any load from the electrical system. It simply veries the voltage to the field of the alternator.
Click to expand...
It carries the field current and allows it to pass through, pass through restricted or not at all.

capnswanny said:
I also added a parallel 14GA wire from the output post on the alternator directly to the Ammeter. I bypassed the Ammeter by connecting all wires to one terminal. I ran a ground direct from battery (-) to the VR Ground plane (chassis). I replaced all the terminals at VR, Alt, and Ballast. I also added a missing ground from the engine to the master cylinder bolt (cleaned), Installed a rebuilt alternator and a new Interstate Battery (fully charged) and tried it again.
Click to expand...
OK. If the ammeter is bypassed then you won't know if its charging but this ...

capnswanny said:
Output at Alternator to Bat (-) @Idle: -0.5VDC (DMM (+) on Battery, (-) on Alternator)
Output at Alternator to Bat (-) @2000RPM: -2.3VDC (DMM (+) on Battery, (-) on Alternator)
Click to expand...
strongly suggests the battery is taking a lot of current.

If the electric fanpowered from the battery, move the connection to the alternator. That will reduce the load on the wiring between the battery and the alternator output stud. That wiring clearly has too much resistance for the load going through it.
 
Original power scheme
Ammeter only shows current to and from battery.
upload_2021-5-21_8-6-17.png


Attach the fan or fan relay to the power supply and only run the fan when the engine is running.
upload_2021-2-12_23-11-30-png.png

In this example above imagine if the current to the headlights lights, ignition and fans was all going down the R6 wire.
How many amps would be going through that line?
Then if the battery needs charging, how much more current would that be?

If you want to run the fan with the engine off, then wire battery more directly to the fan. Something like this will allow the battery to power the fans with the least amount of resistance.
upload_2020-2-1_10-1-14-png.png


And batttery charging would look like this
upload_2020-2-1_9-57-6-png.png
 
Very good points mattax, I need to focus on the current loads. I'll run a separate fused line direct from the alternator to the feed at the fan relay.
Thanks for the assistance!
 
Thanks for checking in Dana, I appreciate it!
Well, I missed my 24 hr deadline
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But, I no longer believe I have a problem with my charging circuit/components, and I'm changing my focus to the load. Also, after reading the instruction sheet included with the VR, I found that it said that the VR may smoke for the first 30 minutes while it burns off the coating that held the coils in place during transit. Read the instructions, right?!

Here's where I am now:
Yesterday I ran a dedicated 12GA wire from the alternator to the fan relay circuit breaker to remove it from the battery charging line as Mattax suggested.
I replaced the 14GA wire that I had run in parallel with the charge line from the alt to the ammeter with 12GA wire just to be on the safer side.
After pulling back all the tape and loom on the wire harness I found that there was no fusible link on the line from the starter relay to the ammeter, and I also found that the PO had hacked in wiring to bypass the melted terminal on the bulkhead connector. I replaced the original wire from ammeter to the starter relay with a 12GA wire through a 30A fuse (it's what I had on hand).
I ran a new 16GA wire from the VR to the alternator field and reconnected the wires to either side of the ammeter in the instrument cluster so I could monitor charge/discharge.
I pulled the VR and checked that nothing did or could contact the resistors on the bottom of the VR.
I also put the battery on the charger for an hour or so to make sure it was topped off.
On startup, everything looked great, battery voltage at idle and throttle looked normal (12.9 to 14VDC). With no accessories on and no cooling fan (it kicks on at ~180F) I noticed that the ammeter showed about a needle’s width toward charge. When applying throttle, it moved up a bit, but settled back to original needles width.
Took her for a drive and found that after a few minutes of driving, the voltage gauge would read high ~14-17VDC, and the ammeter was at the line between center and full charge and would raise lower with RPM. Idling at a stop sign, it would return to center and voltage would drop to about 13-14 VDC. (this is with the cooling fan still not on....it's about 50 degrees here in WA).
Fast forward about 2-3 minutes, and about a 1/4 mile from home, the 30 amp fuse I installed blew. A short walk later (with a new fuse) I limped home and called it a night. I’m pretty sure that I fried the cheap aftermarket radio with the high voltage, and I hope that’s all!

I believe I have something pulling excessive current through the ammeter circuit. I'm going to pick up an 30A ammeter gauge tomorrow, build a test box for it, and start isolating the circuit (divide and conquer) to see what's pulling all the amps.

Since current draw (and battery voltage) increases with engine RPM, do you think it could be something in the coil/distributor circuit?

I've spent today licking my wounds, beer helps ;) And I have a new 3 week deadline (good to have goals:) Son would love to drive the Dart to school before he graduates HS.

Thanks again for reaching back out to me, I REALLY appreciate your help!!
-Corey
 
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