Community Forums

Alpine Dave · 03-10-2014, 03:44 PM

A previous thread http://www.irv2.com/forums/f104/what-alternator-is-on-a-1999-alpine-164673.html contained a discussion about replacing the OEM Leece-Neville alternator on my 1999 Alpine Coach with a Delco Remy 28SI alternator. I just now got around to installing the 28SI and discovered that it does not work with the stock 3 terminal battery isolator that is in my coach.

The problem is that the 28SI is “self exciting” and requires battery voltage present on the B+ output terminal in order to excite the field winding. The stock diode isolator blocks the battery voltage and prevents the alternator from “self exciting”. The 28SI requires an isolator that has an internal “excite” function. This function applies battery voltage to the alternator output momentarily when the ignition is turned on. This enables the alternator to “self excite”.

I just ordered a Cole Hersee 48162 200 amp isolator to replace my stock 200 amp isolator. It has a 4th terminal called “ignition”. I should be able to hook up the “key Switch” wire that went to the old alternator to this terminal in order to activate the “excite” function.

Newer Alpine coaches may already have an isolator with this function. Just check to make sure before installing any of the newer Delco alternators.

The 4th wire that ran to my old alternator is the “sense” lead that comes directly from the chassis battery positive terminal. This connects to the “S” terminal on the 28SI alternator to ensure that the proper charge voltage is maintained at the battery terminals. This terminal was labeled “DUVAC” on the old alternator.

I hope this helps those of you who want to replace your alternator.

Dave

Koop · 03-10-2014, 04:34 PM

Thanks for posting the info Dave.

Alpine Dave · 03-15-2014, 08:42 AM

I installed the Cole Hersee battery isolator and the Delco 28SI alternator is now operating as expected.

For anyone who needs to replace their OEM Leece-Neville alternator and have the 3 terminal battery isolator as I did, may still want to replace the OEM alternator with the 28SI and Cole Hersee combination. The reviews on the Delco 28SI are excellent and the cost of the Delco 28SI with the Cole Hersee 48162 was $235 ($134 + $101) vs. the $354 I was quoted for a Leece-Neville replacement.

Dave Morgan

Algoma · 03-15-2014, 12:23 PM

Did you look at the 48530 as an alternative?

Alpine Dave · 03-16-2014, 07:50 AM

I purchased the Cole Hersee 48162 because that is what the Delco tech support person recommended. I was not aware of the 48530. Looking at it now, it appears it might be a better alternative for about the same price. It would be more efficient than a diode based solution and easier to install. The only issue may be that it would be less reliable due to the fact that it is an electromechanical device as opposed to the solid state diode isolator.

Dave

chillwill · 04-27-2016, 06:25 AM

Dave, I need to know more info about this alternator. I had a issue a month ago and I was at the mercy of roadside service. I have the LN but the guy put a Delco Remy 28SI on it but we did have these details. It was able to get home but the alternator was still warm the next day. I knew something wasn't right. So i replaced it with the original LN and it works fine, but now I'm stuck with a new Delco Remy 28SI that the local store wouldn't take back. After reading your post, I was thinking to use it a spare but I just need to get a good understanding to make it work. I have a 1999 alpine as well with a 8.3 cummins. Thanks

Quote:

Originally Posted by Alpine Dave

A previous thread http://www.irv2.com/forums/f104/what-alternator-is-on-a-1999-alpine-164673.html contained a discussion about replacing the OEM Leece-Neville alternator on my 1999 Alpine Coach with a Delco Remy 28SI alternator. I just now got around to installing the 28SI and discovered that it does not work with the stock 3 terminal battery isolator that is in my coach.

The problem is that the 28SI is “self exciting” and requires battery voltage present on the B+ output terminal in order to excite the field winding. The stock diode isolator blocks the battery voltage and prevents the alternator from “self exciting”. The 28SI requires an isolator that has an internal “excite” function. This function applies battery voltage to the alternator output momentarily when the ignition is turned on. This enables the alternator to “self excite”.

I just ordered a Cole Hersee 48162 200 amp isolator to replace my stock 200 amp isolator. It has a 4th terminal called “ignition”. I should be able to hook up the “key Switch” wire that went to the old alternator to this terminal in order to activate the “excite” function.

Newer Alpine coaches may already have an isolator with this function. Just check to make sure before installing any of the newer Delco alternators.

The 4th wire that ran to my old alternator is the “sense” lead that comes directly from the chassis battery positive terminal. This connects to the “S” terminal on the 28SI alternator to ensure that the proper charge voltage is maintained at the battery terminals. This terminal was labeled “DUVAC” on the old alternator.

I hope this helps those of you who want to replace your alternator.

Dave

twinboat · 04-27-2016, 07:48 AM

This company mentions the 28SI with a DUVAC post.

You may be able to call them and discuss your issue.

http://www.qualitypowerauto.com/

Jeff and Cheryl · 04-27-2016, 01:59 PM

Dave sold his Alpine a couple of years ago and is likely no longer following IRV2.

Alpine Dave · 04-28-2016, 05:31 PM

The problem I had when I first installed the 28SI was the alternator had no output. To get it to start "alternating" I had to momentarily apply 12V to the output of the alternator. This excited the field winding and the 28SI starting putting out 14.7 V as you would expect.

You said your 28SI was over heating. I did not have that problem. After I installed the new isolator with the "excite" function built in. My 28SI alternator worked perfectly. If your unit was overheating, I assume it was operating. If it was operating, you must have an isolator with an "excite" function. Perhaps your 28SI was installed incorrectly and there was some kind of a short on the output. I can't offer you any help on that, except to say if you put the 28SI back in, make sure it is installed correctly (see my original post).

Jeff and Cheryl · 04-28-2016, 06:00 PM

Dave,
OOPS!

chillwill · 05-11-2016, 08:48 AM

I have been reading so many posts concerning the Delco Remy 28SI Alternator. I have the OEM Leece-Neville. If someone could give me a call at (334) 202-6549 and explain the process to me concerning installation, it would be greatly appreciated.

Will

Quote:

Originally Posted by Alpine Dave

A previous thread http://www.irv2.com/forums/f104/what-alternator-is-on-a-1999-alpine-164673.html contained a discussion about replacing the OEM Leece-Neville alternator on my 1999 Alpine Coach with a Delco Remy 28SI alternator. I just now got around to installing the 28SI and discovered that it does not work with the stock 3 terminal battery isolator that is in my coach.

The problem is that the 28SI is “self exciting” and requires battery voltage present on the B+ output terminal in order to excite the field winding. The stock diode isolator blocks the battery voltage and prevents the alternator from “self exciting”. The 28SI requires an isolator that has an internal “excite” function. This function applies battery voltage to the alternator output momentarily when the ignition is turned on. This enables the alternator to “self excite”.

I just ordered a Cole Hersee 48162 200 amp isolator to replace my stock 200 amp isolator. It has a 4th terminal called “ignition”. I should be able to hook up the “key Switch” wire that went to the old alternator to this terminal in order to activate the “excite” function.

Newer Alpine coaches may already have an isolator with this function. Just check to make sure before installing any of the newer Delco alternators.

The 4th wire that ran to my old alternator is the “sense” lead that comes directly from the chassis battery positive terminal. This connects to the “S” terminal on the 28SI alternator to ensure that the proper charge voltage is maintained at the battery terminals. This terminal was labeled “DUVAC” on the old alternator.

I hope this helps those of you who want to replace your alternator.

Dave

twinboat · 05-11-2016, 08:52 AM

Quote:

Originally Posted by chillwill

I have been reading so many posts concerning the Delco Remy 28SI Alternator. I have the OEM Leece-Neville. If someone could give me a call at (334) 202-6549 and explain the process to me concerning installation, it would be greatly appreciated.

Will

I would call the guys at this site.

They say to call for doing what you want to do.
http://www.qualitypowerauto.com/

chillwill · 05-12-2016, 08:07 AM

Thank you twinboat. I will give them a call today.

Quote:

Originally Posted by twinboat

I would call the guys at this site.

They say to call for doing what you want to do.
High Output Alternators & High Torque Starters

kidoo · 06-21-2016, 07:23 AM

I am about to replace my Leece Neville Alt. The old LN one was rebuilt a few months ago and failed, now it is non-repairable. The shop sold me a new Leece Neville, I installed it and now I have to raise the RPM to get it to work. I installed the white wire to the alt but it doesn't make a difference. There is no power to this white wire and the dash idiot light never worked. I ordered a 28 SI and will return the LN.

As per Delco info. sheet, it can be installed with the Battery cable only and it will work, no need to connect any other wire. The relay on my MH is a big round one. The idiot light never worked, it does not illuminate.
http://www.delcoremy.com/Documents/A...tions-10524210

I was wondering if you installed the fan on the alternator as it is supposed to have two internal fans and you should not install the external fan. Link to the info.