"Slight" overcharging

[Norse]

'69 Barracuda
'75 RV 440
Recently replaced Donta-last (Duralast) alternator
Mopar Performance voltage regulator from Mancini's (about 4 years old/maybe 2000 miles on it)

At idle (750rpm-ish) I read 13.9v at the battery, 14.3v at the lug on the alt, 14.0v at the blue wire plug into the volt reg.
Rev up to around 3000rpm at I see 14.3v at the battery, 14.3 at the alt lug, and 14.3v at the volt reg.

The engine compartment wiring harness is from M&H and is about 4 years old. All grounds and connections are good.

Is this a "Danger Will Robinson!!", "Just don't drive it and get a new voltage regulator", or a "Don't worry so much, my dude" situation??

TIA

 

[dadsbee]

Sounds damn near perfect if your running an Odyssey AGM battery inside a script case!

 

[Norse]

Sounds damn near perfect if your running an Odyssey AGM battery inside a script case!

Ah, knew I forgot a component; standard Group 24 battery brand new this year.

 

[Professor Fate]

Right on the money. About 14.4v is what you're looking for.
To put it very basically, a 12v battery needs slightly higher voltage to charge it.

 

[Norse]

Right on the money. About 14.4v is what you're looking for.
To put it very basically, a 12v battery needs slightly higher voltage to charge it.

Good to know, Prof.
My concern extends out of back when I replaced that alternator and tested it the best I got was 13.8v @ 3000rpm.

 

[67Dart273]

First thing you want to do is run it long enough that the battery is "up" and stable, and you want to be sure the VR and engine bay is up to normal temp. Many VR's are temperature sensitive. That is a tiny bit high, not sure I would worry

I've written tons of posts about voltage drop problems in the harness and ground circuit. That would be the next thing.

Mopar, so far as I know was the ONLY manufacturer who combined the field / VR power circuit with the SENSING circuit, which in part, is the root of the entire problem.

 

[Norse]

First thing you want to do is run it long enough that the battery is "up" and stable, and you want to be sure the VR and engine bay is up to normal temp. Many VR's are temperature sensitive. That is a tiny bit high, not sure I would worry

I've written tons of posts about voltage drop problems in the harness and ground circuit. That would be the next thing.

Mopar, so far as I know was the ONLY manufacturer who combined the field / VR power circuit with the SENSING circuit, which in part, is the root of the entire problem.

Bringing her up to temp has always been fun; she ain't got no hood Captain!
(someday when the body work is done she will)
And I keep all my vehicles on Battery Tenders, so I'm sure that might mask an issue.

Thank you though for the reassurance.
At Wyotech I may have got top honors in the Automotive Electrical classes, but it's still voodoo to me. Give me nuts, bolts and a wrench any day.

 

[67Dart273]

To check the VR circuit voltage drop, rig your multimeter to as close as you can get, electrically to the ignition terminal of the VR. Do not disconnect any wiring, it must be all "nromal." Connect the remaining probe, that is, "stab" it directly into the top of the positive battery post.

Turn the key to "run" and take a reading, which should be very low, down in the tenths of one volt. You would like to see "the lower the better." Anything more than .3 AKA 3/10 of 1 volt, investigate. Any drop there will be ADDED to the charging voltage.

My 67 Dart had about 1 1/2V drop. assuming the VR was 14, that means the battery saw 15 1/2 when running.

GROUND

The ground can also do this. Get it warm figure out how to get it up on fast idle to simulate low/ medium cruise RPM and take this reading first with accessories off, and again with everything on, lights, heater, etc

With it running as above, stab one probe HARD into the metal mounting flange of the VR. Stab the other probe into the top of the battery NEG post. Again, you would like very low voltage, zero is perfect

It is always possible that a VR is off a little bit. Someone is selling adjustable ones. I've heard a few good comments, but I really know nothing about them. However, normally you should not need an adustable VR

 

[dadsbee]

Rev up to around 3000rpm at I see 14.3v at the battery, 14.3 at the alt lug, and 14.3v at the volt reg.

 

[MadScientistMat]

14.3 is a reasonable cold charging voltage in summer. You only have a problem if it stays there when the battery heats up to 150 degrees or so. Unless you're running the MP fixed voltage regulator or the parts store special was too cheap to include a $0.25 temperature sensor, the regulator should adjust max charging voltage to match the regulator temperature.

 

[Norse]

14.3 is a reasonable cold charging voltage in summer. You only have a problem if it stays there when the battery heats up to 150 degrees or so. Unless you're running the MP fixed voltage regulator or the parts store special was too cheap to include a $0.25 temperature sensor, the regulator should adjust max charging voltage to match the regulator temperature.

Sadly Mancini doesn't often give details on what they sell.
But here's what I have for reference.
Mopar Performance Voltage Regulator

 

[MadScientistMat]

Sadly Mancini doesn't often give details on what they sell.
But here's what I have for reference.
Mopar Performance Voltage Regulator

That is the fixed regulator and it is reading a bit high - although the voltage itself isn't a problem, particularly since the battery won't get hot without a hood.

 

[Norse]

That is the fixed regulator and it is reading a bit high - although the voltage itself isn't a problem, particularly since the battery won't get hot without a hood.

Yeah, the hood being on the car is a "future me" issue.
Along with the 383...
And the repaint of the engine bay...
And a dash that works...
...

*said with gritted teeth and a forced smile* I LOVE MY HOBBY!!!

 

[MadScientistMat]

It is always possible that a VR is off a little bit. Someone is selling adjustable ones. I've heard a few good comments, but I really know nothing about them. However, normally you should not need an adustable VR

That would be me. But I don't think he needs one here; the voltage is already at a reasonable number.

 

[4spdragtop]

I put about 200 miles on this past weekend with @MadScientistMat adjustable voltage reg. Zero issues, I do have to bump up the V slightly as it was around12(ish) with headlights on