several voltage regulator burn

[madmax2]

Hello
I have burned several VR (solid state) they do not burn instantly, it takes a while. It all started when I took the engine out to make some upgrades.
When they delivered the car to me I noticed that the regulating voltage was 12.9 V, before it was more than 13V and cruising 13.7v and before 14-14.2 v
When I returned home at a traffic light I saw that the voltage had risen to 16-17v. II checked the VR and the transistor was burned, I changed it and it started working again but not with the original voltage values.
With this trial and error I have already burned 4 VR, the other times the circuit was open and the alternator did not charge, the car only ran on battery.
I checked the alternator, Powermaster 95A Mopar round back style, OK.
I checked all the grounds: Battery to the chassis, battery to the engine and a direct ground cable from the battery to the VR. Everything ok but the transistor raises temperature until it burns.
I did a transistor upgrade with a higher IC collector current, and I had time to prove that when regulating there was a drain of >30A... I changed the battery and the drain regulated lowered to 6A, regulating the voltage was 13.2v and cruising 14.0v
I thought I had found the problem and that it was the battery.
I made a 65 mile trip and everything went well, but on the way back the VR burned again.
any ideas.
my setup is a sb mopar 418ci with a Holey HP ecu with Terminator TBI, C-N-P IGN-1A coils. Powermaster 95A dual field (one field to ground)

 

[Dana67Dart]

Fyi

If you can get the transistor number you can replace it. And replace it with a higher current version.

This is my thoughts, no particular order...

1. The regulator might not be able to handle the field current the alternator is needing.
2. There might be an intermittent short in the field wire between the alternator and the regulator.
3. Perhaps there is something (electric choke?) on the field wire.

A way to test for #2 and #3 is run a dedicated wire from the VR to the field terminal on the alternator.

As for the regulator not handling the field current, turn off everything in the car, (radio, lights etc. ) remove the field terminal and run a jumper with an amp meter in series from battery to the field terminal. This will full field the alternator resulting in high voltage charging (18v?) note the amperage. And disconnect the field wire. DO NOT LEAVE IT FULL FIELDING FOR MORE THAN A FEW SECONDS!!!!

Then look at the specs of the VR. Can it handle that?

If not look for a Heavy duty VR that can.

 

[Syleng1]

On my 66’ I had the same trouble. I bought one from Classic Industries that looked just like all the other factory looking VR’s but the electronics inside seem to handle the alternator better.
SN: the car had a great ground from Battery to the engine, I installed an additional ground wire from fire wall to back of the engine for Ha, ha’s at the same time I installed this last VR.( I did have a triangle of grounds but added an additional block to firewall)
Honestly, it’s been over 1 year (knock on wood) with zero issues.

 

[67Dart273]

I don't have any idea of the specs on that regulator, a few comments

12 something is not proper charging voltage. Depending termperature, voltage varies, but on a warm day, normal engine temps, charging/ running voltage after the battery has recovered from starting. should be 13.8--14.2

The why of your regulator problems could be.........

1...that there is a partial short in the alternator field winding, which absolutely can and does happen
2...that regulator may NOT be heavy enough to carry the field current of whatever alternator you are using
3...the alternator you are using may have been improperly rebuilt with a rotor which draws excessive field current, AKA out of a heavier duty unit than this one

You want to check that the VR power terminal is not seeing a voltage drop as this will cause over charging, and that the VR is actually grounded to battery NEG potential, which will also cause over voltage

To check this out, get the thing as close as you can to operating temp and the battery "up" and normal. Get the engine running at fast idle and run this test first with accessories off, and again with lights, heater, etc powered on

Stab one probe of your multimeter into the top of the battery NEG post, and the other probe HARD into the mounting flange of the VR to get through any chrome/ rust/ etc. You should read very little voltage, the less the better, and zero is perfect

==================================

To check the power/ field circuit of the VR, turn the key to "run" with engine stopped. Stab one meter probe into the top of the battery POS post. Leaving all wiring properly connected, probe the IGN terminal of the VR. You will again read a little voltage and the less the better. If you read more than .3--.4V (3/10 of one volt) find out why. If your car is factory wiring, the usual suspects are poor terminals in the bulkhead connector, the igntion switch connector, the switch itself, and possibly at the ammeter. This voltage drop when running causes the VR to ramp up to make the IGN terminal 14V rather than the voltage drop it is seeing. THAT causes the battery to see higher voltage. If the VR is properly operating at 14V, then add that to the voltage you measure in both the ground test and this last test, and the total will be close to what you see at the battery.

 

[67Dart273]

WHAT IS the year/ make model of the vehicle you are working on?

Is it American? Does it have stock or nearly stock wiring? What is the alternator you are using?

 

[madmax2]

It's a argentine Chrysler car, a Dodge GTX 1970 with a early a-body. the electrical circuit was old, no electronic ignition no electronic VR.
I connected the Holley EFI directly to the battery with a circuit separate from the car. The original circuit only handles the alt/VR, starter, lights, dash. The EFI circuit handles the ECU, fuel pump, coils, radiator fan.
Run a wire form battery gnd to VR chasis, I checked the voltage drop between the negative terminal of the battery and the chassis, block, alt, vr... all ok

 

[Dana67Dart]

I installed an additional ground wire from fire wall to back of the engine

If you don't have a battery to body ground strap or battery to engine to body, the ground goes through any path it can find.

 

[Syleng1]

If you don't have a battery to body ground strap or battery to engine to body, the ground goes through any path it can find.

I had the triangle- battery to engine, engine to car and car to battery.
I added the braided wire used on ac cars to the back of my engine to the fire wall- ac Cars had this extra braided wire. I was at wits end on why I kept burning up expensive “electronic conversion VRs.” I just know either this made a difference or I finally found a VR that worked right (or as described)
I’m also running a 60amp alternator not a aftermarket high output.

 

[67Dart273]

60A is very likely to have more field current draw. In the old days with the earlier grounded field, the "big" regulator was what was used, looked like this

Don't know why that photo did not show

 

[Dana67Dart]

Powermaster 95A Mopar round back style,

Just noticed you are in Buenos Aires. Can you get stock parts vs generic aftermarket parts? I'm thinking that the regulator can not handle the load of your alternators field. Perhaps an electromechanical (OEM) style can?

 

[MV8]

I found universal VRs under that part number an form factor that showed equivalency to the common Chrysler VR but showed 4 amp field current and 6 amp max. That would explain lasting a little while at 6 amps. Not crazy about the thin steel heat sink either. I also suggest using the standard regulator.

 

[madmax2]

Update: other electrician find burned the 3 positive diode,
I don't understand why it kept charging.
has not yet burned the VR again

 

[67Dart273]

Update: other electrician find burned the 3 positive diode,
I don't understand why it kept charging.
has not yet burned the VR again

you could have as many as 5 diodes open and it would still charge "a little." Shorted, now that is a different story. When I was in the Navy, and broke, I ran my 69RR for about two weeks til payday with 2 shorted diodes clipped out of the circuit. I didn't drive much at night, nor use the radio. The car had no solid state stuff in it besides the radio. I always figured it turned a stock 37A into about a 10A alternator.

 

[Mattax]

other electrician find burned the 3 positive diode,
I don't understand why it kept charging.
has not yet burned the VR again

I think there is a misunderstanding of "Charging"
In American English it is common to say "charging" to say that the alternator is providing power.
We also commonly will say "Battery" to refer to supply power regardless of whether the power is actually coming from the battery or in fact coming from the alternator.

How this may relate to your observations is as follows.
You have stated the EFI equipment was connected at the battery.
When the engine is running, power is supplied by the alternator at 14 + Volts.
If you are looking at the ammeter, it should only read 'charge' or "+' when the battery is charging.
When the battery has been recharged it should read zero (in the middle)

or

However, because the EFI is now connected to the battery, the ammeter will always read 'charge' with the alternator running.

Let me illustrate this with a diagram.
This shows about 10 amperes flowing to the battery because it is recharging.

When the battery is fully charged, the ammeter shows zero current flowing to the battery.
The alternator is still supplying 14 Volt power to the ignition (and anything else that is switched on).

With EFI and electric fuel pumps connected to the battery, the ammeter will show current going to those items in addition to current to recharge the battery.

So the ammeter is no longer showing battery charging.
It is showing battery charging plus current draw for EFI and anything else that has been connected at the battery.

Damage to the positive diodes on the alternator can be an easy repalcement on some alternators. We've seen photos of alternators used on South American Chryslers that are different than the ones typiclly used on US, UK, and Canadian builds. I don't know what is on your car. The one in the first photo like a Chrysler alternator. The 'round backs' have press in diodes that require a special tool and soldering. The squareback version is bolt in.

I would suggest rewiring the main power supplies in a manner that would supply the EFI and fuel pump without going through the ammeter and fusible link. Some ideas here and more complex ones using a relay here
You may wish to add a voltmeter that is switch on when the key is in run or accessory.
Even though your car is similar in some ways to US built A-bodies, you may want to join For B Bodies Only and have a conversation in Espanol with Nacho-RT74 That will reduce errors in translation.

 

[RedFish]

I didn't read all the previous responces. I did read "dual field" alternator. There's no such thing. It's called isolated field. MA mopar changed from closed field to isolated field as did all other brands. Why you've chosen to remain in stone age, I give up. I read you upgraded a lot of other things. Why not all of the charging system? EDIT ; I had many GM rides roll in with their trio diode partially failed, battery light barely on. Best we could figure poor battery connection was the root cause. We corrected battery connections as part of diode replace, no come backs.

 

[madmax2]

I think there is a misunderstanding of "Charging"
In American English it is common to say "charging" to say that the alternator is providing power.
We also commonly will say "Battery" to refer to supply power regardless of whether the power is actually coming from the battery or in fact coming from the alternator.

How this may relate to your observations is as follows.
You have stated the EFI equipment was connected at the battery.
When the engine is running, power is supplied by the alternator at 14 + Volts.
If you are looking at the ammeter, it should only read 'charge' or "+' when the battery is charging.
When the battery has been recharged it should read zero (in the middle)
View attachment 1716450837 or View attachment 1716450838


However, because the EFI is now connected to the battery, the ammeter will always read 'charge' with the alternator running.

Let me illustrate this with a diagram.
This shows about 10 amperes flowing to the battery because it is recharging.
View attachment 1716450843

When the battery is fully charged, the ammeter shows zero current flowing to the battery.
The alternator is still supplying 14 Volt power to the ignition (and anything else that is switched on).
View attachment 1716450844

With EFI and electric fuel pumps connected to the battery, the ammeter will show current going to those items in addition to current to recharge the battery.
View attachment 1716450849

So the ammeter is no longer showing battery charging.
It is showing battery charging plus current draw for EFI and anything else that has been connected at the battery.

Damage to the positive diodes on the alternator can be an easy repalcement on some alternators. We've seen photos of alternators used on South American Chryslers that are different than the ones typiclly used on US, UK, and Canadian builds. I don't know what is on your car. The one in the first photo like a Chrysler alternator. The 'round backs' have press in diodes that require a special tool and soldering. The squareback version is bolt in.

I would suggest rewiring the main power supplies in a manner that would supply the EFI and fuel pump without going through the ammeter and fusible link. Some ideas here and more complex ones using a relay here
You may wish to add a voltmeter that is switch on when the key is in run or accessory.
Even though your car is similar in some ways to US built A-bodies, you may want to join For B Bodies Only and have a conversation in Espanol with Nacho-RT74 That will reduce errors in translation.

I believe the alternator's BAT terminal goes directly to the starter relay.

I have the original electrical system. I connected the EFI to a separate circuit directly connected to the battery (ECU, fuel pump, coils, and radiator fans). The alternator, RV, starter, lights, heater, horn, and wipers are connected to the original circuit via the ammeter.
They only share the battery.
I turn the ECU on/off with a separate key connected to 12V (battery +).

I bought a new Powermaster alternator from U.S.

 

[madmax2]

Now the voltmeter read +14v at idle.

 

[madmax2]

I didn't read all the previous responces. I did read "dual field" alternator. There's no such thing. It's called isolated field. MA mopar changed from closed field to isolated field as did all other brands. Why you've chosen to remain in stone age, I give up. I read you upgraded a lot of other things. Why not all of the charging system? EDIT ; I had many GM rides roll in with their trio diode partially failed, battery light barely on. Best we could figure poor battery connection was the root cause. We corrected battery connections as part of diode replace, no come backs.

Because I thought it wasn't necessary, that 95 amps would be enough.
In the future, I'll replace the alternator with a 160 amp one-wire.

 

[Mattax]

Because I thought it wasn't necessary, that 95 amps would be enough.
In the future, I'll replace the alternator with a 160 amp one-wire.

The system only needs an alternator that can provide the power demanded.
The factory system only needs about 28 amps at 14 V to handle running the engine, plus lights on, wipers running, heater fan running, brake lights.
Add to that the maximum power these new devices can draw. Then you will have good baseline for the power that the alternator should be able to produce for your car's needs. You may wish to add another 10 to 15 amps to account for battery recharging after start up.

Larger alternators weigh more, sometimes take up more room, and those with high ratings often are less capable at low rpm.
An example of higher rated alternator that is less capable at low rpm is shown on this chart of GM 10SI alternators.

In this example the "72 Amps" 10 SI will need a much smaller pulley to provide the same power as the "63 amp" alternator at low engine rpms.

Also consider that more power is often possible due to a stronger electromagnetic field. Unless the design is much more efficient, the stronger field is developed by drawing more current. So again at low rpm this can be less efficient and steals amps when they are least available from the alternator.

I think you should consider some alternators based on designs of the later 1980s and 90s and a matching regulator. There's a Denso alternator that is relative popular and my understanding is not too difficult to fit.

 

[Mattax]

I believe the alternator's BAT terminal goes directly to the starter relay.

Does this feed have a maxi-fuse or fusible link?

I have the original electrical system. I connected the EFI to a separate circuit directly connected to the battery (ECU, fuel pump, coils, and radiator fans). The alternator, RV, starter, lights, heater, horn, and wipers are connected to the original circuit via the ammeter.
They only share the battery.
I turn the ECU on/off with a separate key connected to 12V (battery +).

Together this should keep the new loads off of the original charging system.
Its not clear whether the alternator output feed has been retained. If power from the alternator is only connected at the starter relay, then the fusible link and ammeter segments will be seeing more load than intended.

Something like this will work OK.
The ammeter will not show much if anything because it is generally a longer path.

Without the alternator original feed, current to the alternator field, the lights, etc have to go through 16 gage fusible link and the ammeter section. That's a longer path with more junctions.

 

[Mattax]

If you want to keep the ammeter functional, then I think the way to do it is with a relay between the new fusebox amd then route a new wire through a gromment in the firewall to the correct side of the ammeter.

Or if the ammeter is not very important to you, something like this should work.

The bigger fusbile link protects against shorts in the alternator. The original fusible link protects against shorts in the original 12 gage wires.
Connect a voltmeter to the new fusebox or one of the switched circuits in the factory fusebox or other switched location.

In both of these schemes, the original key switch turns everything on.
Good luck.

 

[madmax2]

@Mattax To be honest, I don't remember how the alternator is connected and I don't have the car handy to check it right now.
View attachment 1716451686

I'm also thinking of swap the alternator for one of these one-wire...

 

[Mattax]

I gave you the best advise I could.
Without solid information then its a question of gambling.
Lots of people happy to take your money.

 

[madmax2]

I posted several photos but for some reason I can't see them.

I think my circuit is this, remember my car is an early a-body, no electric VR, no electronic ignition.

 

[madmax2]

I gave you the best advise I could.
Without solid information then its a question of gambling.
Lots of people happy to take your money.

Thank you for your help and advice, I speak and write English poorly, sometimes I have trouble understanding the meaning of sentences.