(FINAL Update )...Alternator voltage too high, question

[Cloud_Dancer]

Mine is a 2003 Spartan chassis, 8.3 350HP Cummins engine, Leece Neville HD alternator with integral voltage regulator. It set at the lake for a month, hooked up to shore power, and I went to check it out, cranked right up, but but the dashboard voltmeter started showing 14.5 to 15 volts. I had never seen this before. I checked the 6 years old house batteries, one was weak, replaced all 4 (golf cart 6 volt). NO change. Tried it with shore power disconnected, no change.
Question: What's the best guess? Change the 2 chassis group 31 batteries, or is it the voltage regulator? Thanks

[MEXICOWANDERER]

Was not meant for you 🙂 I should have said this plainly. Sorry. Read up on how to FULL FIELD your alternator to positively isolate reg failure from alternator failure.

OEM Leece-Neville voltage regulators were so unreliable I used Transpo voltage regulators instead. So don't feel bad. I replaced working OEM LN regulators for drill when rebuilding.

Given today's MOSFET devices and surface mount protection devices, it takes a lot of foresight and planning to make an inferior voltage regulator. You bet your butt, it is intentional. A shield of course is the modern rebuilding shop whose reputation depends on winnowing out the junk.

These people are rebuilder's suppliers. Their recommendations will not steer you wrong...

ROMAINE ELECTRIC - WASHINGTON. CORPORATE HEADQUARTERS. 8811 S. 208th St. Kent, WA 98031. Phone - 800-426-5005

[Daytonaman]

MW your way ahead of me; I have to pull the LN unit and look for part#'s.
Your knowlege is very helpful as I always learn from your posts.
The fail term on the reg is putting out 0v.
The charge out is 15.4v Bat sense is 13v ok.
The "alt fail" (6v 86a) relay is not pulling in so alt lite is on.
I am hoping to replace the reg with the same part # because the alt (LN 200a) is otherwise ok.
Looks like a DUVAC; using a diode iso.
2002 Monaco Sig.
There is no BIRD BS, so this system is simple and works well.
Don't want to rewire the charge system.
Thanks for your expert advice.
greg.

[MEXICOWANDERER]

A stator to negative connection is used. Some alternators provide an "N" or "R" terminal for this.

With a 3-amp axial diode in-line this new connection can power a 5-wire relay like a Bosch type. You will need to connect the wire to any stator terminal on the alternator.

Then it runs to and through the relay coil.
Exits the other relay coil terminal and then connects to chassis negative.

Run an new wire to the ignition switch circuit. Connect it to an outboard relay terminal. There are 3 remaining relay terminals. Choose one of the two most OUTBOARD of the terminals.

The center-most relay terminal connects to a wire then to a two wire pilot light bulb or audible alarm. one wire left to connect. Connect the other bulb or alarm wire to chassis negative.

No stator voltage means it will not pull the relay contacts open and open the light or alarm circuit. Being powered by ignition the light comes on when the key is switched on verifying the circuit is viable.

I you use Ignition Switch terminal A, the circuit will operate only with ignition switch turned on. The accessory position will not activate the circuit.

A muted pleasant chime is the hot setup for me. Vehicle gauges are less than worthless. I note that I tend to see them when steam boils out from under the hood, a knocking sound is out of rhythm with Ziggy Marley, or the lights go dim.

[Daytonaman]

My alternator regulator has an "alternator failure" output that controls a 6v 86a relay in the low current plate. This relay lights the "alt fail" lamp on the dash.
Do replacement reg have this output term?

[Cloud_Dancer]

Recieved the voltage regulator, and it's the latest correct one (with fins). Total cost (including sales tax) is $48.17.
I checked for shorted rotor windings, all OK, and I assembled and installed the alternator. Cranked it up, and all dash gauges and warning lights and status indicators are normal. YeeeHaaaw!
What I will never forget is all the weird things/symptoms that I was getting with the dash gauges and system-status lights,....all because it was charging too high. What's interesting is that about 3 years ago I got VERY similar symptoms (except the voltmeter needle was moving back and forth, almost full scale). That time, the cause was one broken alternator brush. So, in the future, if I see the same symptoms, I will simply first remove the alternator and bench test it.
I want to thank everyone on this forum for all the help. And, I want to wish MexWanderer the best of luck, and speedy a recovery.

[MEXICOWANDERER]

Fair price

BEFORE you bolt the reg on, do this...

Slip the brushes into their holes. Boiing they're sticking up via their spring

With your meter set to TWO HUNDRED OHMS (or nearest setting)

With one test lead push the brush most rear down firmly with the lead probe.

With the OTHER test lead touch the tip to anyplace on the alternator's case

The meter reading should remain blinking "1", open circuit infinite resistance.

The meter dial should be well demarcated. 200 ohms, not 2,000, 20,000, or 2M

For curiosity probe the front rush. You WILL get a reading there of anywhere from 3.0 ohms to god knows how high (due to carbon smearing on the brass slip ring. But the rear brush has to be grounded or both test leads have to be used on both brushes. One lead on each brush.

Those rotor windings have been famous for grounding shorts.

[Cloud_Dancer]

From a very friendly local nice guy (he's a rebuilder of starters and alternators),...........$46....plus UPS ground.
The other prices hovered around $98, except for the quote from AJ Electric in North Carolina...$60

[MEXICOWANDERER]

And if I may what was the 37-teeth-showing, "most friendly" price?

[Cloud_Dancer]

It took several days to shop around for this voltage regulator. I learned that the part number has changed 3 times, and the most recent one (the one with the cooling fins) is R-24103726-S. I had to order it, to get the most friendly price. I will report back when I install it and test it.

[MEXICOWANDERER]

Not having your regulator connected to my voltage regulator tester I have to play cautious. -0- mistakes. Disconnect voltage sense lead terminal from it's stud, insulate wire terminal then re-test. Dash gauge seems reasonably accurate. This final test will bracket the problem like a pro in a $120/hr shop would do it. No need to connect tester to alt. Remove sense wire, start engine look at dash gauge. I am eliminating the possibility of a negative side short in the rotor field. This is an A circuit reg.

[Kayteg1]

In short >>>> VR malfunctions.
Get it replaced.

[Cloud_Dancer]

Kayteg1 wrote:
Voltage regulator is what is says.
Most of us associate it with alternator brushes, as that is the only way in US to buy, but the unit has electronic circuit inside as well.
When the circuit fails - whole thing needs to be replaced (you can save good brushes for re-soldering them next time)
With readouts >15 V there is not much to think about.

Not clear on what you wrote. Are you saying it's open and shut, the voltage regulator is the culprit?

[Kayteg1]

Voltage regulator is what is says.
Most of us associate it with alternator brushes, as that is the only way in US to buy, but the unit has electronic circuit inside as well.
When the circuit fails - whole thing needs to be replaced (you can save good brushes for re-soldering them next time)
With readouts >15 V there is not much to think about.

[Cloud_Dancer]

I'm back! I was sidetracked with a weird starter-not-cranking problem. Read about it in the Class A Motorhome forum. I got help from Tom/Barb.
*
New chassis batteries are installed, checking close to 13 volts. I managed to attach clip leads to the alternator output terminal/post (+) and to the Remote Sense terminal/post. With everything off, alternator(+) lead indicates 12.76 V, and remote sense lead indicates 12.77 v.
With engine running at idle, dash voltmeter indicates 14.9 to 15.3 volts. Alternator (+) lead indicates 15.9 to 16.5 volts. Remote sense lead indicates 16.6 volts. I shut down the engine (the voltage wasn't decreasing).
Other than a few years ago, removing the alternator, removing the voltage regulator and replacing the brushes I simply don't have enough experience with symptoms vs remedy. Off the top of my head I tend to lean towards replacing the voltage regulator. But, I will wait to hear from MexicoWanderer and otheres. Thanks