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Author Topic: Altenator over charging.  (Read 185 times)

Mark Beavin

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Altenator over charging.
« on: August 15, 2019, 08:12:55 PM »
My alt is over charging. Is the regulator built in or is it separate on a 1996 cat diesel  30' Monterey.
Mark Beavin  Judi Binderman
FMC 491464
1996 Beaver Monterey 30'
3126 Cat Diesel 250 HP

Gerald Farris

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Re: Altenator over charging.
« Reply #1 on: August 15, 2019, 10:01:25 PM »
Mark,
Your coach uses a DUVAC alternator (probably 160 amp Leese Neville), and the voltage regulator is built into the alternator. However, because the alternator output is ran through a battery isolator, the regulator depends on the sense wire to determine the proper charging voltage. Therefore, before you condemn the voltage regulator, thoroughly diagnose the system, especially the sense wire for the proper voltage and connection at the alternator.\

Gerald   
2002 Solitaire (2017 -  )
2000 Marquis, C12 (2004 - 2017)
1993 Patriot  (2000-2004)
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Richard Davis

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Re: Altenator over charging.
« Reply #2 on: August 15, 2019, 11:48:17 PM »
I had the same issue on my 1998 Cat 3126 with the Leese-Neville alternator.  It was charging 17 volts all the time.  I replaced the voltage regulator.  It is rather straight forward since it is right on top of the alternator held down with 4 screws.  If you replace the voltage regulator, a couple of tricks.  1) The contacts are on springs that go down into the alternator.  In order to install the springs, you must push them down into place and install two small pins (straightened paper clips or small drill bits) through the two small holes in the alternator case to hold the springs down while you install the top and start the 4 screws.  You must remove the pins to release the springs before tightening down the top.  2)  There is a notch in the top to allow for the two small wires to go out and not be pinched when you install the top.  Failure to insure that the wires are in the notch will pinch the wires when you tighten down the 4 screws (you can guess how I know that).
Good luck!  I hope it is that simple for you.  I eventually had to have the alternator rebuilt.  If you need to do that, I strongly recommend you have the original Leese-Neville rebuilt since they are much better than most any new one you can find today.

Richard 
06 Monterey Ventura IV, C9 400 hp
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Mark Beavin

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Re: Altenator over charging.
« Reply #3 on: August 16, 2019, 10:50:27 AM »
Turns out I have a Delco/Remy alt. Probably changed some where along the line. Also turns out my Free Voltage test from Harbor freight was 3 volts to high. Got out my old trusty load tester and all voltages were good to go. Whew!!! But will try and find a replacement alt to have on hand just in case. Any Part numbers?
Mark Beavin  Judi Binderman
FMC 491464
1996 Beaver Monterey 30'
3126 Cat Diesel 250 HP

Mark Beavin

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Re: Altenator over charging.
« Reply #4 on: August 16, 2019, 11:52:36 AM »
What Amp alt should I look to buy as a spare?
Mark Beavin  Judi Binderman
FMC 491464
1996 Beaver Monterey 30'
3126 Cat Diesel 250 HP

Joel Ashley

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Re: Altenator over charging.
« Reply #5 on: August 16, 2019, 12:33:48 PM »
As Gerald alluded, the standard is a Leese Neville 160 amp.
Joel and Lee Rae Ashley
Clackamas, Oregon
36.9 ft. 2006 Monterey Ventura IV, aka"Monty Rae"
C9 400HP Cat
towing a 1997 Ford Explorer Limited, aka "Pearl"

Gerald Farris

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Re: Altenator over charging.
« Reply #6 on: August 16, 2019, 07:20:31 PM »
Mark,
The Leece Neville part number is A0012824LC, but there are many manufacturers that make an acceptable replacement. The main requirements are a J180 mount for a DUVAC application that means it has a remote sense wire and is ignition excited. The standard alternator is rated at 160 amp and 200 amp units are available, but some of the early Monterey coaches even used a 140 amp alternator.

Gerald
2002 Solitaire (2017 -  )
2000 Marquis, C12 (2004 - 2017)
1993 Patriot  (2000-2004)