Foretravel Owners' Forum For owners and Fans of Foretravel Motorcoaches September 07, 2025 ...

Delco Remy 28SI Alternator Installation

October 09, 2020, 06:40:57 pm

I recently completed the installation of a new alternator.  I know this is a common and not particularly challenging upgrade, but I decided to create a thread covering the installation anyway.  I hope it will give some of our less mechanically adventurous members the confidence to tackle similar projects on their coach, when and/or if it becomes necessary.

When we purchased our coach in 2013 it came with a Leece Neville 8LHA2070VA alternator (sales number 110-555, 12 volt, 130 amp).  This was not the original factory installed unit - it was a replacement.  I had some problems right off the bat getting it to function properly, but eventually made it work.  I also made tentative plans to someday replace it with an upgraded model.  The long story of my early alternator hassles are linked below if interested.

Brain Teaser (Electrical)

Fast forward to 2020.  Two years ago I started thinking seriously about finally buying a better alternator.  At that time I purchased and installed a new Victron ArgoFET 200A battery isolator.  I was already looking seriously at the Delco line of alternators, and I knew from Forum reading that they require an isolator with a "alternator energize input".  The Victron isolators met that requirement.

'93 U280 Isolator Panel Upgrade

Then, about a year ago I purchased a Delco 28SI 200A J180 alternator.  I just recently got around to installing it.  I don't like to rush into things... 

The alternator mounting bracket on our 1993 U280 (Cummins C8.3L) is a J180 style.  Because the brace attached to the lower mounting hole is moveable, any J180 style alternator (long hinge or short hinge) can be fitted to the bracket.

First step is to remove the old alternator.  This is pretty straightforward, although the mounting bolts may be pretty tight and require some forceful persuasion.  Once removed, take the old unit to your work bench.  The 28SI does not come with a pulley, so this must be transferred from the old unit.  This is where I encountered a "learning experience".  The pulley on my old LN alternator was secured by a big nut threaded onto the end of the shaft.  I could not see any obvious way to hold the pulley or shaft while loosening the nut.  GOOGLE to the rescue!  I found a YouTube video describing the procedure.  Shorter version: you grip the pulley tightly with one (gloved in my case) hand while attacking the retaining nut with the impact wrench.  I just happened to have a 1/2" drive Craftsman air impact in my tool box, and it quickly spun the nut off with no problem.

https://www.youtube.com/watch?v=pbDWKg8kpQU

I was somewhat concerned about pulley alignment because the LN and the Delco are set up differently.  The LN has a 1/2" thick fan on the shaft between the pulley and the alternator body.  The Delco has an internal fan.  But when I set both units side-by-side I could see there would be no problem.  The Delco case is shaped differently and sticks out enough to place the pulley in the same position (relative to the mounts) as the LN.  See photos below for comparison.

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Re: Delco Remy 28SI Alternator Installation

Reply #1 – October 09, 2020, 06:41:27 pm

The pulley on the LN fits on a shaft with a machined keyway and key.  I used a Craftsman pulley removal tool to pop it off the shaft.  The Delco shaft does not use a key to locate the pulley.  Rather, the pulley fits very tightly on a smooth shaft and is secured by a large nut.  The shaft has a hex key recess in the end.  To tighten the pulley retaining nut you hold a backup on the shaft with a large Allen wrench.

Once the pulley was locked on the Delco shaft, it was time to address the supporting components.

I had already decided to upgrade the charging cable and the sense wire.  The OEM charging cable was 2 AWG and the sense wire was 18 AWG.  I elected to upgrade to 2/0 welding cable for the charge cable, and to 10 AWG for the sense wire.  Wishing to avoid trips to town, I purchased the required materials online.  The sense wire is simply a length of red 10 AWG wire with a 10 AWG fuse holder (5 amp) attached to one end.  I found my PVC pipe cutting tool worked nicely for cutting the 2/0 welding cable.  I don't know how well it would work on larger gauge cables.  I decided to learn how to crimp my own cable ends.  I purchased a FTZ tool and the matching FTZ Power Lugs, and was able to produce a very nice quality charging cable with little effort.  (Crimping tools were recently discussed here on another thread)  See photos below:

Once the charging and sense cables were ready, it was time for installation.  To avoid making sparks, I removed the POS and NEG cables from my single AGM8D start battery.  This was when I encountered another "learning experience".  With the start battery totally disconnected, I started working on removing the old charging cable and sense wire from the isolator panel.  To my surprise, I found the start battery powered circuits were still HOT!  I have 2 LED volt meters mounted on my dash.  One reads coach battery voltage and the other reads start battery voltage.  I went inside the coach and looked at the meters.  Sure enough, the start battery meter was showing 12.9 volts....with the start battery totally disconnected.  I could turn the ignition key to "ON" and everything on the dash that is powered off the start battery came to life.  Really weird!

After much head scratching, probing around with my multimeter, and email consultation with Forum member Peter (very sharp on electrical stuff) we finally deduced that the source of the "cross feed" was my Trik-L-Start device.  It was connected to the 2 battery posts on the isolator.  When I removed the Trik-L-Start lead from the isolator coach battery post, the start battery circuit went dead.  I tried removing all charging sources from the coach batteries by disconnecting our solar controllers and unplugging from shore power, and then re-connecting the Trik-L-Start lead to the isolator.  Once again, the start battery circuits came to life.

I don't know if my Trik-L-Start device is faulty, or if this is "normal" behavior.  The instructions say if there is no charging source connected to the coach batteries, then the Trik-L-Start should be inactive.  But perhaps having the start battery totally disconnected confuses the Trik-L-Start in some way.  I don't know.  I don't think the way my device is acting is normal.  I will attempt to contact the manufacturer and see what they say.  For now, I am going to leave it disconnected.

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Re: Delco Remy 28SI Alternator Installation

Reply #2 – October 09, 2020, 06:42:02 pm

After I got the weird Trik-L-Start mystery figured out I got to thinking about the isolator.  Do I really need a isolator?  I decided that I do not need it.  Now, I am not suggesting that this arrangement is for everyone.  I am not recommending that members should dump their isolator.  I am simply stating that I feel that I can get along very nicely without it.

Removing the isolator continues my long-time pursuit of simplifying my coach electrical system.  In years past, I had removed the main shore power/generator factory ATS and replaced it with a manual switch.  When we had our inverter upgraded to a Magnum MS2812 we removed the separate factory inverter transfer switch and used the internal switch in the Magnum to do that job.  Removing the isolator will be the final step in the simplification process.

To accomplish this change, I decided to run the alternator charging cable and the sense cable directly to the POS post on the start battery.  Thus the 200A Delco will, under normal conditions, only be responsible for charging the start battery.

The coach batteries will normally be charged by one (or both) of two ways: either by our solar charging system, or by the onboard charger built into the Magnum inverter.  The inverter/charger is either powered from shore power or by the generator.

When I rebuilt my isolator panel I replaced my standard boost solenoid with a Blue Sea Technology 7701 ML (magnetic latching) solenoid.  This device has a very high current carrying capacity, and only uses power to move between the "open" and "closed" positions.  Once positioned, it draws zero power.

SO, without a isolator, my two battery banks will normally be totally separated.  Depending on circumstances, I might want to connect both banks together, either for a starting boost or to charge both banks from one charging source.  This is easily done with the dash control switch for the ML Solenoid.  For instance, I could charge all 3 batteries with the alternator when driving, or I can charge all 3 batteries with the inverter/charger when hooked to shore power, or with the solar panels when dry camping.

Every time I enter the coach I can glance at my dash volt meters to see the exact SOC of both battery circuits.  Easy to keep tabs! 

Photos below show the Delco in place, plus the new configuration of my isolator panel sans isolator.  I have also added a corrected copy of the pertinent portion of the 12 volt automotive wiring diagram for our coach.  A copy is also included in my Owner's Manual for future reference.

Like I said, this arrangement is not for every owner, but I think I will enjoy having total manual control over my electrical system.

Cheers!

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Re: Delco Remy 28SI Alternator Installation

Reply #3 – October 09, 2020, 07:08:24 pm

Like thinking of great minds today as I was thinking about our coaches charging systems.

I swapped my rebuilt LN adjustable alternator with a non adjustable same 160 amp unit.

After watching my magnum charger adjust the float level down to 13 volts at 100 degree battery temps and checking the dash lighter voltages both were at 13.74.

Way overcharging the gels.  The red tops might handle this ok as they were made to dissipate heat.  But long drives I think is or has hurt the gels.

 Better might be 2 alternators? The one that's on the engine now to be used for the chassis batteries.

The adjustable one for the gels?  Better yet maybe a marine voltage regulator for the house battery system to match the inverter/charger temp compensating profile?

Or just put back on the adjustable one and turn it up or down at the rear for coarse adjustments.

But watching the two dash readouts during the day the float voltages went from 13.0 to 13.34 as the temps changed.

So the most work and hassle would be 2 alternators with the house side temp controlled.

Plus I may need to upgrade the main power wire from the batteries to the combiner.  It seems the voltage drop has the combiner dropping below the 12.75 unhooking limit from the temp compensating charger in hot weather.  13 at the charger panel then 30 feet drops the voltage so the combiner unlatches.

Anyone know what wire size runs from the battery to the isolater/combiner at the rear. 

I assume it's not 4.0?

Your hard work on installing your setup brought back into my long term thoughts on doing a temp controlled charging system

Or just put back the oem alternator and adjust it down like Foretravel did 23 years ago...

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Re: Delco Remy 28SI Alternator Installation

Reply #4 – October 09, 2020, 07:29:10 pm

Well done Chuck, I like the kiss method

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