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Alternator replacing

I'm replacing my original alternator with the exact same Leece Neville. Doesn't it need to be adjusted on output? 1996, 8.3 Cummins
1996 U295-36, Cummins 300hp, 8.3. Build number 4864. Vin number 1F97D536XTNO54271. Purchased October 31, 2019.

Re: Alternator replacing

Reply #1 –
Keep the old one for a spare and carry it with you.
previous 1984 35 ft ORED 250 HP 3208 Cat       
previous 1998 40 ft U295 CAI 325 hp Cummins
previous 2003 40 Ft u320 build #6140 450 Cummins M11.                                                         
1999 Mazda Miata
Ron, Nancy, Tipper the cat, Max The dog
1997 U 270 36 ft build number 5174 8.3 Cummins

Re: Alternator replacing

Reply #2 –
If you have a diode based OEM style isolator they consume about 0.7 volts through the diodes. The OEM LN alternators had output voltage increased to compensate for the loss to keep voltage at the batteries about 13.8v.  Those adjustments and final output depend a bit on battery type and your situation.
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: Alternator replacing

Reply #3 –
I'm keeping the old one as a spare, since these are not stocked. I assume I could run the genny to get home if you lose the alternator
1996 U295-36, Cummins 300hp, 8.3. Build number 4864. Vin number 1F97D536XTNO54271. Purchased October 31, 2019.

Re: Alternator replacing

Reply #4 –
Quote from: dans96u295ft –
I assume I could run the genny to get home if you lose the alternator

Yes, just turn on boost and continue on. In fact I just had someone burn up an alternator and had to drive in from N. Dakota like that. I plan on doing a show & tell when when I have time to get it rebuilt as several have ask.

Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: Alternator replacing

Reply #5 –
If someone wants a functioning, adjustable voltage 160 amp LN alternator that was in my 2001 U320 let me know.  I kept it as a spare but I would rather see it in use than sitting on a shelf.

Update
It is off to a new home, better there than on my shelf.

Thanks
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: Alternator replacing

Reply #6 –
Quote from: dans96u295ft –
I'm replacing my original alternator with the exact same Leece Neville. Doesn't it need to be adjusted on output? 1996, 8.3 Cummins

Yes.*  Does not?  It do.  Your solid state battery isolator has a 0.7V voltage drop across the diode.

Art

*Unless you have a voltage sense wire.
1992 Foretravel Grand Villa
U225 SBID Build No. 4134
1986 Rockwood Driftwood
1968 S.I.A.T.A. Spring
1962 Studebaker Lark
1986 Honda VF700C
1983 Honda VF750C
Charlie, the Dog was broken out of jail 24 Oct 2023
N1RPN
AA1OH (H)e who must be obeyed.

Re: Alternator replacing

Reply #7 –
Quote from: Roger & Susan in Home2 –
If someone wants a functioning, adjustable voltage 160 amp LN alternator that was in my 2001 U320 let me know.  I kept it as a spare but I would rather see it in use than sitting on a shelf.
I'll take it if it's free and you have a commercial shipping account. It's a heavy devil. I got rid of our dash AC and am going install a second alternator where the compressor was. No more isolator and will replace the existing boost solenoid with a latching model.. C/H 24200 Amazon.com: Cole Hersee 24200 Latching Solenoid: Automotive

Pierce

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Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Alternator replacing

Reply #8 –
Quote from: Old Toolmaker –
Yes.*  Does not?  It do.  Your solid state battery isolator has a 0.7V voltage drop across the diode.

Art

*Unless you have a voltage sense wire.

IF this truly is a DUVAC alternator, there is a SENSE WIRE/TERMINAL that is on the chassis battery side of the battery isolator. This automatically compensates for the voltage loss in the diode-based battery isolator.

So, alternator is told by the sense wire/terminal to put out enough voltage such that subtracting the loss across the diode-based isolator results in exactly the correct voltage to the battery.  May some small adjustment need to be made to conform with a particular brand/technology of battery-- certainly.  But the loss across the diode-based isolator is already taken into account.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Alternator replacing

Reply #9 –
Yes, it is a DUVAC
1996 U295-36, Cummins 300hp, 8.3. Build number 4864. Vin number 1F97D536XTNO54271. Purchased October 31, 2019.

Re: Alternator replacing

Reply #10 –
The aternator can be easily coverted to DUVAC. See this page for modifications: Technical Services

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Alternator replacing

Reply #11 –
What is DUVAC?  What good is it?
 This is my LN and it has the same tag.

Pat,
Pat/Blue Angel
1995 U240 36ft
MC# 16511
Build# 4653

Re: Alternator replacing

Reply #12 –
Quote from: pthurman48 –
What is DUVAC?  What good is it?
To find the answer to this question, read this thread from the first post, and read the thread linked below.

What is DUVAC?
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Alternator replacing

Reply #13 –
Quote from: pthurman48 –
What is DUVAC?  What good is it?
 This is my LN and it has the same tag.

Pat,

The important thing about a DUVAC alternator is that it has an external SENSE wire that senses voltage on the on the chassis battery side of the diode-based isolator.  This is important, as correct voltage "downstream" of the isolator is what matters.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Alternator replacing

Reply #14 –
Pat,

With pic. yours is set  as a DUVAC looks like it could be OEM even.

Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."