Alt gauge going to the extreme right suddenly when accelerating.

[1968 Dart 270]

Hi, I have a question and hope somebody here can help me. I just got in my car to go home from work. It was running fine this morning. I got in it and started to drive home and got about a block and noticed the ALT gauge would now go to the extreme right on acceleration. It never did this before. I am pulled over now as I dont want to drive it if it's overcharging the battery and risk destroying it or worse. Anyone have this happen? Outside of somehow disconnecting the alternator and driving it home on the battery any other ideas?

 

[67Dart273]

If you have the older 69/ earlier VR just pull the "push on" wire off at the VR OR the field wire off at the alternator. If you have the later 70/ later system, yank either field wire off at the alternator.

Examine the green wire from the alternator field to the VR. On a 70/ later system, that wire might be grounding. On the earlier system, sounds like a sticking/ bad VR. Make sure the VR is well grounded

 

[1968 Dart 270]

If you have the older 69/ earlier VR just pull the "push on" wire off at the VR OR the field wire off at the alternator. If you have the later 70/ later system, yank either field wire off at the alternator.

Examine the green wire from the alternator field to the VR. On a 70/ later system, that wire might be grounding. On the earlier system, sounds like a sticking/ bad VR. Make sure the VR is well grounded

Thanks. I realized I forgot to State what year the car is it's my 1968 Dodge Dart 270 that has Factory 273 V8 everything is stock. The thing is if the voltage regulator is sticking would it still go down to the middle at idle? It's only when I touch the accelerator lightly that it goes all the way almost to the C.

 

[1968 Dart 270]

Well I looked for the old fashioned metal style of regulator that I'm used to seeing. The only thing I can see is this plastic piece of junk thats not original mounted to the firewall of the car

 

[dadsbee]

Turn your lights on high beam and it might kick it back to get you home...

 

[1968 Dart 270]

Turn your lights on high beam and it might kick it back to get you home...

Yeah I already tried that when it started happening. I turned the high beams on turn the blinkers on turned on every electrical thing to try and create as much drag as I could. I just pulled the wire off the alternator and drove home on the battery. One things for certain about this car it always keeps me busy. In this case it was a crappy Chinese part,and that's the only one the local parts stores carry when I looked online now. Well I guess I have to look for a high quality voltage regulator now. Supposedly Syandard Vr101 is the correct one for my car.
I'm just glad I watch my gauges all the time and caught this right when it happened. Hopefully it didn't do any damage to my battery. I had to turn the key off in traffic and get out and yank the wire.

 

[Mattax]

I just pulled the wire off the alternator and drove home on the battery.

That was the safest move, assuming you were close enough that you could make it on battery alone. I've driven a couple hours on battery but not with the lights the whole time.

Well I guess I have to look for a high quality voltage regulator now. Supposedly Syandard Vr101 is the correct one for my car.

These days I don't know that Standard's is any better than anyone elses.
If its a 'rebuilt' alternator, many draw more current than the factory spec'd. I suspect that's why some of the transisterized regulators fail early.
See if you can find a new old replacement stock (NOS or NORS) like Dibbons did.

VR-101

Today I picked up an old school voltage regulator still in the box at my old school auto parts store here in Mexico for about $9.00 USD.

www.forabodiesonly.com

I'm just glad I watch my gauges all the time and caught this right when it happened. Hopefully it didn't do any damage to my battery. I had to turn the key off in traffic and get out and yank the wire.

Good move.
When the regulator fails to shut off power to the rotor, voltage increases with rpm.
Electrical devices draw more current when provided power at higher voltage.
If the lights were on they might have become brighter with increasing rpm. At some votlage they would draw so much current the filaments would burn out.
Similarly a battery draws more current when voltage goes up. Even if its fully charged. In your case its was a little low 'cause the car had just been started. That may explain why the ammeter pegged to 40 amps charging.

I guess the question is why the old one needed replacing?
Maybe something else is going on that damaged two VRs.

 

[1968 Dart 270]

That was the safest move, assuming you were close enough that you could make it on battery alone. I've driven a couple hours on battery but not with the lights the whole time.

These days I don't know that Standard's is any better than anyone elses.
If its a 'rebuilt' alternator, many draw more current than the factory spec'd. I suspect that's why some of the transisterized regulators fail early.
See if you can find a new old replacement stock (NOS or NORS) like Dibbons did.

http://[URL]https://www.forabodiesonly.com/mopar/threads/vr-101.514175/#post-1973850216

[/URL]



Good move.
When the regulator fails to shut off power to the rotor, voltage increases with rpm.
Electrical devices draw more current when provided power at higher voltage.
If the lights were on they might have become brighter with increasing rpm. At some votlage they would draw so much current the filaments would burn out.
Similarly a battery draws more current when voltage goes up. Even if its fully charged. In your case its was a little low 'cause the car had just been started. That may explain why the ammeter pegged to 40 amps charging.

I guess the question is why the old one needed replacing?
Maybe something else is going on that damaged two VRs.

I have no idea why it failed. Ive had the car a few years and it had that regulator when I bought it and it worked fine until today. Other people here had said the Standard vr101 was better than these Chinese plastic box replacements. It's 57 bucks plus tax for another one of the plastic ones from autozone,but it has a lifetime warranty. The have the Standard vr101 on Amazon new for $38. There is also a vr101t (thrift) model. For $27 I'm not sure how much more cheaply made the vr-101t is, it could be the only difference is the warranty.

 

[Mattax]

Well the nice thing about the mechanical regulators is they will reveal what went wrong with a quick inspection.

Also, I think I misunderstood. I thought the plastic one frone 'zone was a recent replacement for one that failed.

 

[1968 Dart 270]

Well the nice thing about the mechanical regulators is they will reveal what went wrong with a quick inspection.

Also, I think I misunderstood. I thought the plastic one frone 'zone was a recent replacement for one that failed.

No,it was on there when I bought the car. I noticed it because it stood out being made of plastic like that. Oreillys has the standard vr101 for the same price as the plastic duralast autozone one. Same price,both have lifetime warranty. Or i can get it on Amazon brand new and save $22 but it doesn't have a lifetime warranty.
My other cars with generators have mechanical regulators. I dont recall any of them failing,but I've had the generators fail.

 

[4spdragtop]

You can get a modernized version of the voltage regulator. It has electronic guts vs oem(electrical).
Stay away from "T" stuff from SMP, yep it's thrift store junk. Some of there other stuff is also. Elec dist pickup was junk, physically wouldn't fit/work.

 

[Phreakish]

Years ago I had a dodge alternator that failed internally somehow and did the same thing. Would go full charge with some rpm. If I flipped the field wires it would put a huge drain on the battery. I would not replicate on a bench test.
It over volted enough one time to blow all the lights out before burning the fusible link (80s dodge).
I would do what @67Dart273 said and and also check field voltage with the wires disconnected from the alt to help rule the regulator in or out. A bad regulator or short outside of the alternator should show up with some meter or test light checks.

 

[Kendog 170]

FYI A member @MadScientistMat is making regulators. I believe 1970 up right now but has plans on making them for older models. I'm sure you'll get something now but something to keep in mind if it interests you. Good Luck.
Who would like to beta test one of my new voltage regulators?

 

[MadScientistMat]

Thanks for the mention! The first production batch of 1970 and later regulators should be ready in June, with single field regulators on the drawing board now.

 

[1968 Dart 270]

Thanks for the mention! The first production batch of 1970 and later regulators should be ready in June, with single field regulators on the drawing board now.

Will you make the 1969 and earlier regulators look like factory original parts? I'm sure you could hide the electronics inside the same style housing

 

[MadScientistMat]

Getting a stamped metal cover on the regulator is way too expensive and installing in a reconditioned original housing is a logistics nightmare. One possible option is to offer a 3d printed cover that looks close to stock, although it will not stand up to close inspection.

The 1970 and later one looks nothing like the stock unit, but does fit the stock location and wiring.

 

[Bewy]

So what changes with an increase in alt speed? How the brushes contact the slip rings? This is an old alt, so would expect brushes to be worn down. I am not sure whether this would cause the OPs problem.

 

[Mattax]

So what changes with an increase in alt speed? How the brushes contact the slip rings? This is an old alt, so would expect brushes to be worn down. I am not sure whether this would cause the OPs problem.

When the electromagnetic field is constant, the potential energy goes up with rpm.
Regulators work by making and breaking the power to the field and/or restricting the current.

 

[MDchanic]

The first production batch of 1970 and later regulators should be ready in June, with single field regulators on the drawing board now.

Until and unless I end up replacing my original alternator, I'm eagerly awaiting your "hot-regulated" (instead of "ground-regulated") units.

As far as format, might it be possible to design it to attach, and heat-sink, to an original-style case, whether actual original mechanical, or newer SMP-style case with a little chip inside? I think most people who would use one of these would be capable of modifying an old case to accept a new mechanism.
Of course, adding in the possible variables in how the user could (mis-)install something like that could cause a warranty nightmare...
I guess it all depends on how much heat it has to shed.

Also, a 3D-printed cover might blend in more than one might think, if the buyer were to sand off any waviness and paint it with gloss black paint, just like the original.

Just thinking out loud...

- Eric

 

[Mattax]

FBO

 

[MDchanic]

FBO

My point exactly. Depending on requirements for board size, most of us could drill out three rivets, possibly drill a couple of other holes, and screw a new board in there with proper attachment of the heat sink to the base.

- Eric

 

[Mattax]

My point exactly. Depending on requirements for board size, most of us could drill out three rivets, possibly drill a couple of other holes, and screw a new board in there with proper attachment of the heat sink to the base.

- Eric

The question is why.

What would a board made by one of us do, or how would it be different, then the board FBO is having made, or from electro-mechanical internals?

 

[Mattax]

What concerns me here is this

I have no idea why it failed. Ive had the car a few years and it had that regulator when I bought it and it worked fine until today.

Did the plastic covered regulator fail because of a quality issue, or some other cause. Why did it fail to break the circuit?
One thing I suspect is that none of these were made to handle the current draw more than double of the factory expectation. So the field current draw is one possibility when the alternator has been replaced.

 

[MDchanic]

A fine and reasonable question.

Presumably because the corporate outsourced unit is more prone to failure due to design and/or materials shortcuts than would be one designed from a clean slate using quality components by someone who personally cares that it works well.

But without actual failure statistics on the SMP or "No Name" units, I will admit that this answer is based entirely on subjective, rather than objective information.

I'd ask Matt that question.

- Eric

 

[67Dart273]

Just some general bla bla. It may have failed, becuz, china. The transistor may not be able to handle the field current. I'm sayin that it may not handle the field current of a PROPERLY operating alternator. Additionally, Not all alternators draw the same field current, and with the poor reputation of rebuilders, VERY possible that a rebuilt rotor draws more than it should

And then you could have a rotor that has a possible short, also causing it to draw extra current.