overcharging the battery HELP

[71 360 scamp]

I got my car back from the mechanic 2 days ago. I noticed the alternator gauge was pegged to the right + side. I called him and he said it was probably just because the battery was dead so I charge the battery with a trickle charger (battery is 8 months old) same problem. I was then advised to get a new voltage regulator and then a new alternator, and still the same problem.

Before I changed the regulator and alternator, the battery was getting 17 volts at idle. Not sure how much it’s getting now but I assume it’s the same based on the gauge reading.

I Don't think it’s the alternator gauge just giving me a bad reading because when I turned my lights on they immediately blew out from an over charge.

Ocassionly i hear a click (behind the dash?) and the gauge goes into the middle were it should be but 1 second later it hikes back up the the + side

Anyone know what could be wrong?

 

[toolmanmike]

Mine did the same thing and my regulator wasn't tight to the firewall and wasn't grounding good enough. Could be a bad regulator too.

 

[71 360 scamp]

The voltage regulator is as tight as possible. A brand new-bad regulator? that would suck, is there anyway to test the it?

 

[twofosho]

Check all the wires between the alternator and the voltage regulator with an ohm meter to make sure a broken wire is not the source of your problem. If you haven't got one, I've seen them (VOM) as cheap as four bucks on sale at Harbor freight.
And yes, you wouldn't be the first to get a bad voltage regulator brand new out of the box.

 

[67Dart273]

There's several possibilities

First, what kind of work did this shop do?

Second, why did you change the alternator/ regulator, because of this problem, or other reasons.

So first, do this:

Identify the green wire hooked to one of the alternator field connections (one should have blue, one green, hooked to the two push on terminals of the alternator

Unhook the green, start the car, see if it charges. If not, OK

If so, the problem is right in the alternator, one brush is grounded and should not be.

If it stopped charging with the green unhooked, now hook it back up, go up to the regulator and unhook the connector at the regulator. If it stops charging, OK

If not, you have a short in the harness in the field circuit

If it stopped charging in either case, now do this:

Turn the key to run, engine off. Hook your voltmeter, one probe to the battery positive, other probe to the blue wire on the alternator. You are looking for a VERY low reading, the lower the better. Over 1/2 volt is way too much, and it should be less

Now check the regulator ground. Start the car and run at a low idle with the voltage not over 15, if possible, by adjusting the idle speed.

Put one meter probe directly onto the battery negative post, and the other directly onto the regulator case. Be sure to "stab" through any rust/ chrome/ paint on the regulator

Here, you are looking for a VERY low reading, the lower the better, zero would be perfect. Anything over .2V (two tenths of a volt) shows you have a ground problem between the regulator case and the battery

IF the above all checks out, you still have a bad regulator. "New," by the way, does not mean "good."

 

[mopar340dave]

Make sure the cable going from the engine block/cylinder head is grounded to the negative post on your battery.
When I went from a built 340 with solid mounts to a mild 318 with rubber mounts I forgot to add a ground cable and i had the same problem.

 

[71 360 scamp]

Thanks for all the responses, the mechanic fixed an ignition problem for me: a new ignition switch and fixed some screwing wiring from the igniton switch to the ballast resistor. i changed the alternator and regulator becasue of this problem.
The cable is grounded to the negative post.


I unhooked the green-didnt charge
I then unhooked the plug to the regulator-didnt charge

I'm going to buy a multimeter and run the other tests tomorrow, ill check back in then.
Thanks again

 

[67Dart273]

OK, keep us posted on this thread.

 

[cudamark]

And whatever you do, don't drive it like that unless you want to cook and/or possibly blow up the battery. Plus as you have found out, don't turn any lights or accessories on either until the problem is solved.

 

[mopar340dave]

I didn't say that right...the cable needs to go from the negative post to the block AND the frame.ops:

 

[71 360 scamp]

There's several possibilities


Turn the key to run, engine off. Hook your voltmeter, one probe to the battery positive, other probe to the blue wire on the alternator. You are looking for a VERY low reading, the lower the better. Over 1/2 volt is way too much, and it should be less

Im getting .8volts when running this test, The other test seemed inconclusive, the meter was jumping all over the place, mostly in the negitives.

What do i do now?

 

[67Dart273]

There's several possibilities


Turn the key to run, engine off. Hook your voltmeter, one probe to the battery positive, other probe to the blue wire on the alternator. You are looking for a VERY low reading, the lower the better. Over 1/2 volt is way too much, and it should be less

Im getting .8volts when running this test, The other test seemed inconclusive, the meter was jumping all over the place, mostly in the negitives.

What do i do now?

OK, .8V is WAY too much, and indicates a drop problem in the harness. Your no1 and no2 suspects are the bulkhead connector, the connector on the ignition switch, next after those two the switch itself, and last, a problem in the ammeter circuit (Bad connections at the ammeter.

(The "voltage drop" path is from the battery--fuse link--through the bulkhead--to the ammeter circuit--to the ignition switch connector--through the switch--back out the ignition switch connector--back out the bulkhead connector--to the ballast resistor/ and the IGN terminal of the regulator)

To "get around" the ground checking problem with your meter, try this instead:

Make up a temporary ground wire, at LEAST no10 wire, and connect directly from the battery neg. post to the regulator mounting frame.

Then run the car and see if the voltage goes down some.

IF IT DOES, then make ANOTHER temporary bypass (just for testing) for the "hot side" Make up another jumper, can be 14 or larger wire, from the battery positive to the "key" side of the coil resistor, or hook right to the regulator. "Tee" this into the regulator IGN terminal, and be aware the ignition will be getting power all the time.

Now run the engine again and see if the charge voltage has gone down to somewhere around 13.8-14.5

IF NEITHER of these jumpers make much difference in the charge voltage, change the regulator.

(You are running a front mount battery? The battery is grounded to the engine block?)

 

[71 360 scamp]

Alright...this is a bit (by that i mean a lot) over my head. Think im just going to take it back to the mechanic. But i really really appreciate all your help. Thanks everyone.

And yes front battery grounded to the block

 

[Sussmad]

I am having same issue although not as frequently; my gauge pegs when I first start the car and then settles quickly (minute or 2 usually). Occasionally it will peg while driving but only for a minute. Lights go really bright when this happens so I assume it is not just the gauge itself. I replaced the ground from the wall to the block and thought it helped but the problem reappeared. I have a good ground from the battery to the block but no ground from battery to the frame. If I am understanding this discussion right I also need this? Would going into the radiator mounting screw be a good place? I am obviously new to this, thanks

 

[Demonracer]

If any of you are running the older point type regulator, you might take the cover off and look at the points. If the have a high spot, take a points file and file it flat. I had this problem in the race car on the return road and it bulged the battery case, almost blew the battery up. If you are running the newer PC regulator try changing it out, it might be the problem. Again as suggested before, DO NOT drive the car or turn the accessories (lights, radio, etc.) until fixed. It will blow the battery up, of fry your wiring.

Bill S.

 

[67Dart273]

I am having same issue although not as frequently; my gauge pegs when I first start the car and then settles quickly (minute or 2 usually). Occasionally it will peg while driving but only for a minute. Lights go really bright when this happens so I assume it is not just the gauge itself. I replaced the ground from the wall to the block and thought it helped but the problem reappeared. I have a good ground from the battery to the block but no ground from battery to the frame. If I am understanding this discussion right I also need this? Would going into the radiator mounting screw be a good place? I am obviously new to this, thanks

Is this the older car with the old style (69/ earlier) regulator? If so, this sounds more like a sticking regulator (mechanical relay type) rather than a wiring / ground problem.

IT COULD BE either, but that would be my first guess. Make sure the mounting of the regulator is clean and tight, IE scrape away the paint/ rust from the mount holes, and use star washers under the bolts

 

[Sussmad]

Is this the older car with the old style (69/ earlier) regulator? If so, this sounds more like a sticking regulator (mechanical relay type) rather than a wiring / ground problem.

63 Valiant: the previous owner had updated to Mopar orange box electronic ignition as well as that flatback regulator which almost matches the type in my 1970 Dart. The 70 has plug in type electrical connection where as the one in the 63 has more of an open (wire to bolt) connection. Sorry for the lame description. I'm not sure what type of regulator I should look for. The connection to the wall seems tight but I'll check to see if there are any washers. Thanks

 

[Sussmad]

Is this the older car with the old style (69/ earlier) regulator? If so, this sounds more like a sticking regulator (mechanical relay type) rather than a wiring / ground problem.

63 Valiant: the previous owner had updated to Mopar orange box electronic ignition as well as that flatback regulator which almost matches the type in my 1970 Dart. The 70 has plug in type electrical connection where as the one in the 63 has more of an open (wire to bolt) connection. Sorry for the lame description. I'm not sure what type of regulator I should look for. The connection to the wall seems tight but I'll check to see if there are any washers. Thanks

 

[67Dart273]

Is this the older car with the old style (69/ earlier) regulator? If so, this sounds more like a sticking regulator (mechanical relay type) rather than a wiring / ground problem.

63 Valiant: the previous owner had updated to Mopar orange box electronic ignition as well as that flatback regulator which almost matches the type in my 1970 Dart. The 70 has plug in type electrical connection where as the one in the 63 has more of an open (wire to bolt) connection. Sorry for the lame description. I'm not sure what type of regulator I should look for. The connection to the wall seems tight but I'll check to see if there are any washers. Thanks

Sounds like you have the 70/ later system, which is electronic, the regulator should look like this:

It that is acting up, it's either

a bad battery

a ground or harness voltage drop problem

or the regulator is intermittently bad, which would be rare.

Another possibility is that the push-on field terminal at the althernator for the GREEN wire is cracked and intermittentyl shorting to ground, which would cause the alternator to go "full field."

 

[Sussmad]

Thanks 67Dart273: I'll test the battery-although it hasn't failed me yet: The alternator at full field is an indication of the battery not recharging? sometimes? I will also check the green wire and hopefully not have to look for a ground or harness problem,don't know if I able enough for that. My regulator is similar to the one in the picture; just blue with not as neat as of a connecting outlet. Sorry to have hijacked this tread.

 

[Sussmad]

Hey 67Dart: I just found this in a box of extra parts I have; I think it is from a 71/72 Valiant; I am going to try to swap it out and see what happens. I assume the electrical connectors are readily available.

 

[67Dart273]

Yeah, clean those terminals on the regulator, though. They look awful

 

[DUSTPAN340]

what a great thread...seems I have had the same problem with my 70....also when I have the hood open and car running...I hear the battery cooking....will have to see what happens with new motor in...with new paint..don't want battery to go boom on me...will replace the regulator while doing motor....
this site is always full of help....

 

[wjajr]

I have run a ground loop picking up voltage regulator, spark controller, alternator case, and back to negative battery terminal to get all those devices electrically the same, and to eliminate ant voltage drop.

You should have a heavy ground cable from negative battery terminal to engine block, connections at both ends have to be clean and free of any corrosion, paint build up, and grease. You will need to disconnect these to check them.

There needs to be a ground strap from rear end of head to fire wall, and grounding conductors with good clean connections bonding headlight sockets to car body, and for better performance I have connected lighting grounds into a second grounding loop connected to negative battery terminal.

As for electronic voltage regulators becoming faulty, it happens. I had installed a VR 128 or VR1001, can’t remember which, in my 67 Dart to correct an over charge problem, after a few months it failed. It would peg the amp gage, cause the alternator to whine under full load, than it would snap out of it after several seconds…

Another source of overcharging is powering an electric choke or such high draw device from the ignition circuit, say at the high side of the ballast resistor. This causes the voltage regulator to see a voltage drop in that circuit, and it than regulates the alternator to put out more voltage, which in turn creates an over charge problem that will boil the battery, and burn out lights.

Any resistance device such as an electric choke must be powered by a relay system from the alternator power lug. This will take the heavy load off of the ignition circuit, and the small amount of power it takes to trigger a relay via the ignition circuit won’t disrupt the voltage balance between regulator and alternator.

One more thing, I have installed a power cut off switch at the battery, the one with a green knob Wal-Mart sells for about seven bucks. I don’t trust these old car’s electrical systems, additionally, one can disconnect battery very quickly when visited by the fire gods with the flick of the wrist.

 

[Belvedere66]

There's several possibilities

First, what kind of work did this shop do?

Second, why did you change the alternator/ regulator, because of this problem, or other reasons.

So first, do this:

Identify the green wire hooked to one of the alternator field connections (one should have blue, one green, hooked to the two push on terminals of the alternator

Unhook the green, start the car, see if it charges. If not, OK

If so, the problem is right in the alternator, one brush is grounded and should not be.

If it stopped charging with the green unhooked, now hook it back up, go up to the regulator and unhook the connector at the regulator. If it stops charging, OK

If not, you have a short in the harness in the field circuit

If it stopped charging in either case, now do this:

Turn the key to run, engine off. Hook your voltmeter, one probe to the battery positive, other probe to the blue wire on the alternator. You are looking for a VERY low reading, the lower the better. Over 1/2 volt is way too much, and it should be less

Now check the regulator ground. Start the car and run at a low idle with the voltage not over 15, if possible, by adjusting the idle speed.

Put one meter probe directly onto the battery negative post, and the other directly onto the regulator case. Be sure to "stab" through any rust/ chrome/ paint on the regulator

Here, you are looking for a VERY low reading, the lower the better, zero would be perfect. Anything over .2V (two tenths of a volt) shows you have a ground problem between the regulator case and the battery

IF the above all checks out, you still have a bad regulator. "New," by the way, does not mean "good."

Old thread, fresh problem. I'm having the same issue. Suddenly overcharging like crazy (16.4v at idle). The radio shuts off when the rpms are increased and turns back on with idle. While driving the dash smokes and the alt gauge is pegged. I did the first two tests with positive results. I did the voltage tests and with the key to Run and the leads on batt positive and blue wire at alternator it read 1.2V. the regulator case to ground test was 0.02v which is good.

So what would be causing 1.2v at the blue alt wire? And would my regulator be the culprit? My alternator screams at me if everything hooked up. Sounds fine when green field is disconnected and nothing is charging.