Keep burning Voltage Regulators

[danf_fl]

1968 Charger.
Replace points with electronics.
Replaced alternator.
Checked connections.
Ballast resistor read 0.3 on multimeter.
But I keep burning voltage regulators. Why?

 

[QuickBpBp]

Make sure the alternator is good. Just because it's replaced or new that doesn't mean it's good.

 

[Don Frelier]

Make sure the alternator is good. Just because it's replaced or new that doesn't mean it's good.

You can't get anything good anymore...

 

[danf_fl]

Took it to a place and alternator checks good (or so they said). With ballast resistor, what should the resistance be?
As a side note, when I install a new voltage regulator, I get 13.4 V showing on battery when running, then I see some smoke coming from voltage regulator. Alternator gauge has some fluctuation, but shows charging. in time, voltage regulator burns out and no charge.

 

[bcOH67]

Good ground on the regulator? Generally heat/smoke is resistance no? I’d run a ground line directly to it from the battery and see what happens.

…but then again I come here a lot a with questions because I don’t know what I’m doing . So you might not want to listen to me

 

[danf_fl]

Ran an extra (temporary) ground to eliminate that.
Triple checked ground wires. All are good.

 

[Don Frelier]

The field wire to the alternator might have a spot where the insulation is cracked/chipped and it's making some contact with the block somewhere.
Take a good look at that wire between the regulator and the alternator. Replace if you find a bad spot anywhere.

 

[68 Sport Satellite]

throwing this out there to consider all possibilities - doesn't the VR make ground contact at the firewall? It needs to be metal to metal, so unpainted at that bolt location. I just scuff mine up with steel wool around the bolt hole and it's hidden by the VR.

 

[vance.dykes]

1968 Charger.
Replace points with electronics.
Replaced alternator.
Checked connections.
Ballast resistor read 0.3 on multimeter.
But I keep burning voltage regulators. Why?

if you don't want to read the service manual that is a free down load you tube has picture showes

 

[LowBikeMike]

Took it to a place and alternator checks good (or so they said). With ballast resistor, what should the resistance be?
As a side note, when I install a new voltage regulator, I get 13.4 V showing on battery when running, then I see some smoke coming from voltage regulator. Alternator gauge has some fluctuation, but shows charging. in time, voltage regulator burns out and no charge.

Are you referencing the Ammeter? If so, the needle should be centered after a few minutes of run time. If it is always showing a charge I would check the wiring and battery condition

 

[danf_fl]

Yep. Even grounded VR with a ground wire (although temporary). Tested continuity of base of VR to another grounding point.

 

[QuickBpBp]

1968 Charger.
Replace points with electronics.
Replaced alternator.
Checked connections.
Ballast resistor read 0.3 on multimeter.
But I keep burning voltage regulators. Why?

You are running the newer voltage regulator as you can't use the stock one you had... Electronic ignition needs more voltage and it why it needs upgraded.

 

[danf_fl]

Are you referencing the Ammeter? If so, the needle should be centered after a few minutes of run time. If it is always showing a charge I would check the wiring and battery condition

Battery just removed from charger, 1 year old. Ammeter shows charging (with a little fluctuation) until VR burns up.
Ballast resistor has 0.3, but service manual says it should have 0.5-0.6. Could that be part of my problem?

 

[danf_fl]

You are running the newer voltage regulator as you can't use the stock one you had... Electronic ignition needs more voltage and it why it needs upgraded.

Do you have a part number and source? Thanks!

 

[QuickBpBp]

Do you have a part number and source? Thanks!

This is what I used on my cars that did not have electronic ignition when I converted them..

1970 MOPAR PERFORMANCE PRE V8 MODELS VOLTAGE REGULATOR OEM GENUINE P3690732 | eBay

 

[danf_fl]

Thanks!

 

[Cranky]

Are you referencing the Ammeter? If so, the needle should be centered after a few minutes of run time. If it is always showing a charge I would check the wiring and battery condition

That happens when the battery is fully charged and then when the engine starts, the alternator will replace what the starter just used. Also, when showing charging all the time, the battery could be going bad. Been down that road a time or two. Found out the battery was junk when it wouldn't start the car after I had left the house and had to get a jump to get home. Funny how it got me started to begin with....

 

[R413]

Don’t sand the paint under grounded modules. The ground happens through the bolt threads and the bolt head.

How many millions of cars do the car companies build and they NEVER sand any paint under grounded parts. How many factory original cars have you worked on that have the paint sanded under modules? NONE!

It doesn’t ground there and will just cause rust.

 

[RemCharger]

Battery just removed from charger, 1 year old. Ammeter shows charging (with a little fluctuation) until VR burns up.
Ballast resistor has 0.3, but service manual says it should have 0.5-0.6. Could that be part of my problem?

The resistor is for the ignition system.

 

[451Mopar]

The ballast resistor does sound like the resistance is a bit low, but has no effect on the charging system.

"Replace points with electronics." Does this relate to the ignition system or the voltage regulator?

Trying to figure out if your using the 1968 style voltage regulator with the single field connection alternator where the regulator controls field power on the positive side and the other field is grounded to the alternator case, or the later style electronic voltage regulator and alternator where one field connection gets positive power from the key-on ignition power, and then the voltage regulator controls the field power on the ground side connection?

If "Replace points with electronics." means you replaced the points type regulator with an electronic version with the older style alternator, then you will be looking for a short between the regulator output and the alternator field brush connection.

Quick test would be to disconnect the end at the alternator field connection and the other end at the regulator output to isolate the wire and check resistance to ground. The meter or test light should show no connection between the wire and ground.
Next would be to check the alternator field resistance which should be a few ohms, but static test might not show problems internal to the alternator, usually just the brush holder isolation.

Anyhow, if using the 1968 charging system style regulator and alternator, I would just try a different / replacement alternator and run a new 14 AWG field connection wire from the regulator output to the alternator field and just ignore the old field wire.

If we are talking the newer style charging system, then the regulator case ground, under hood heat, and the regulator quality are the major issues. If there was a short on the negative field wire to the regulator, the alternator would try to output maximum power to the battery. It could also be that the alternator field resistance is too low.