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Topic: Wrong Alternator? (Read 1289 times) previous topic - next topic

Wrong Alternator?

I recently purchased a '91 U280 with a 3208 Cat.  I have been chasing a strange wiring issue and I think I may have found the cause.  When I bought the coach the PO mentioned he had to pull the fuse for the speedometer/hour meter or the engine battery would run down.  He also mentioned he had replaced the alternator.  What I found was even with the fuse out, the load side of the speedometer/hour meter fuse was hot.  With the fuse in, this would bypass the ignition solenoid and power the whole system.  After tracing and disconnecting wires from one end of the coach to the other I found that only removing the alternator sense lead from the isolator would finally cut the power to the speedometer/hour meter connection.  I found a number of odd splices in the wiring on top of the engine, and noticed the alternator did not seem to match the ones I have seen on similar coaches on the forum.  It has a Leece-Neville, marked 110-555JHO.  When I looked that one up on the web I noticed it was shown with two leads coming out of the voltage regulator, both connecting to the output terminals.  Mine has the red lead spliced into a blue wire in the harness instead, which I believe is the wire to the speedometer/hour meter circuit, and must also be spliced to the original sense lead as well.  I suspect that when the original alternator failed the truck repair shop he took the coach to installed the wrong alternator and tried to improvise a hookup that would work and kind of failed.  My currently plan is to review the splices in the harness on the engine and try to return it to the stock configuration, but if the alternator is wrong I guess I will have to replace that as well.  Has anyone run into anything similar?  Any suggestions?  Is this a great opportunity for an upgrade?
Mike & Lilli
1991 GV U280 36' SBI, 3208 Cat, Build #3825
4320 Watts Solar
Kansas City, MO

Re: Wrong Alternator?

Reply #1 –
If you haven't already, review the recent thread on DUVAC alternators.  Might give you some clue as to what is wrong with your setup.

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: Wrong Alternator?

Reply #2 –
I have been following that thread, but I think my GV predates the DUVAC system.
Mike & Lilli
1991 GV U280 36' SBI, 3208 Cat, Build #3825
4320 Watts Solar
Kansas City, MO

Re: Wrong Alternator?

Reply #3 –
If you do not have a wiring diagram get with James Triana at Foretravel and see if he can get you one.
96 U270 BUILD 4810
85 380SL
Drummonds TN.

Re: Wrong Alternator?

Reply #4 –
Quote from: rvtinker –
My currently plan is to review the splices in the harness on the engine and try to return it to the stock configuration, but if the alternator is wrong I guess I will have to replace that as well.  Has anyone run into anything similar?  Any suggestions?  Is this a great opportunity for an upgrade?
Mike,

You are on the right track.  First question: does your coach have a diode based battery isolator?  See photo below of the isolator on my coach.  This is a common setup on most older Foretravel coaches.  If you do have a isolator, then as you have deduced, the alternator on your coach is incorrect.  It only has provision for two cables to connect to the back: the big POS and NEG cables (see photo below).  The failed attempt by (whoever) to make this unit work with your coach is the root cause of your electrical problems.

SO, what to do?  First, disconnect the little wire spliced into the red lead on the alternator.  This should solve your electrical mystery, and return the alternator to stock working condition.  Next, you must decide what you want to do to "fix" your coach.  You have two choices.

If it is working properly, you can keep the alternator you have, and replace the diode based isolator with a "smart" combiner.  This will perform the same function as the isolator, but will work with the alternator now in place.  Search the term "combiner" on this Forum for more info.

OR, you can keep your isolator, and either modify or replace your alternator.  Some "2-cable" alternators can be modified to work with the isolator.  This requires somehow adding the capability to "sense" the voltage on your start battery bank.  If your present alternator cannot be modified, then it must be replaced.  In that case you have a number of choices, several of which are mentioned in the DUVAC thread linked in my prior post.

Here's some more:  Delco Replacements for LEECE NEVILLE 110-555JHO | Delco Remy  (28Si and 36Si are remote sense)

You are not the first member to run into this problem.  It is easily corrected...you just need to decide what you want to do.

AND, if you don't have the wiring diagrams for your coach, TRY to get copies of them, one way or another.  They are essential when working on and trouble shooting the electrical systems.

Good luck!
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: Wrong Alternator?

Reply #5 –
As has been said here many times, the sense wire(wired directly to the start battery or battery terminal on the isolator) is connected to the small terminal next to the big + terminal on the alternator.  A wire that is hot only when the ignition is on is wired to the other small terminal.  I bet you have a standard truck alternator that was mis-wired to work.  You need to install the correct alternator and wire it correctly.
Regards,
Brett

'99 42' Foretravel Xtreme
'14 Brown Motorsports Stacker
'05 Chevy SSR
'02 BMW R1150R

Re: Wrong Alternator?

Reply #6 –
Duvac article is very informative. IDK the correct answer, as the duvac may well be outdated and there may be simpler more robust isolators or combiners in order to skin the same cat. My PO spent $1100 for 2 mobile experts to correct his alternator charging issue, prior to my arrival. The simple fact was the main belts driving the alternator were slipping badly, and I could visually see that while watching the engine run. The mobile experts knocked some wiring loose that drove the hydraulic fan, and took all of the isolator wires off, stuck a bolt thru them and used at least one whole roll of electrical tape to wrap it up, because they could not figure the alternator out.
Old Phart Phred, EIEIO
89 GV ored 36' #3405 300 hp cat 3208 ATAAC side radiator, mountain tamer exhaust brake

Re: Wrong Alternator?

Reply #7 –
Yes Chuck, I have the isolator like yours, and my alternator looks just like the one pictured, except for the red lead being spliced into the engine wiring harness.  I have a potential source for a discounted Delco alternator with the sense connector, so that is the direction I think I will go.  I do have the wiring diagrams, though my copy is rather poor.  I was actually working on trying to redraw it in full color, but parts are illegible.  I guess Tuesday I will have to call down to Foretravel, join the Motorcade, and see what assistance I can get.  I don't have the receipt where the PO put on the alternator, but I did find one where he paid over $300 trying to resolve the electrical problems without success.  It looks like he saved money on the alternator and spent it on troubleshooting. 
Mike & Lilli
1991 GV U280 36' SBI, 3208 Cat, Build #3825
4320 Watts Solar
Kansas City, MO

Re: Wrong Alternator?

Reply #8 –
Mike, if your isolator is like the one in the photo above and is located behind the rear tires, you might want to consider replacing it with a newer one and moving things to the space at the foot of the bed. I don't know what (or if) Foretravel was thinking when they thought putting high current electrical connections behind a pair of tires, exposed to the weather, was a good idea. Several of us have moved that isolator to under the bed. It isn't all that hard, but you may have to lengthen a few wires. Just label everything BEFORE you unhook it. Also make sure that ALL electricity is off (power cord, disconnect all batteries).

Re: Wrong Alternator?

Reply #9 –
Quote from: rvtinker –
I have a potential source for a discounted Delco alternator with the sense connector, so that is the direction I think I will go.
If you buy a replacement alternator, do not be concerned if it only has provision for one extra small wire, rather than two.  As Brett mentioned above, some DUVAC type alternators have two small terminals:  "remote sense" and "hot with ignition".  Other DUVAC alternators have only the "remote sense" connection because they are "self exciting".  The alternator on my coach is this type.  Either type will work fine with the isolator.  Just pay close attention to the wiring instructions when you install it.

PS: Your first year membership in the Motorcade Club is free.  When you call FOT ask for Beverly - she will fix you up.
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: Wrong Alternator?

Reply #10 –
Quote from: kb0zke –
Mike, if your isolator is like the one in the photo above and is located behind the rear tires, you might want to consider replacing it with a newer one and moving things to the space at the foot of the bed.
Yes, that is in the works as well, but may have to wait for warmer weather.  It was only 15 degrees in the storage building yesterday.  I am sticking to the most essential tasks first, so I can get it inspected and registered in Missouri.
Mike & Lilli
1991 GV U280 36' SBI, 3208 Cat, Build #3825
4320 Watts Solar
Kansas City, MO

Re: Wrong Alternator?

Reply #11 –
These Leece Neville alternators seem to be short lived.  After taking one apart, replacing the diode block and converting to self excited Duvac was underwhelmed with internal build quality.  Delco, on the other hand, seem to be bulletproof and the 28si referenced above is what I'll replace with when this one goes. 
"Not so  long ago we were a nation of risk takers, riding five million pounds of  thrust straight into space."  Joe Gresh
Chuck Pearson
1996 U295
2018 Can Am X3 TurboRS

Re: Wrong Alternator?

Reply #12 –
I don't know about Leece-Neville being short lived some of these seem to be original 10-20 years old! I'm sure there are better out there though.
Bruce, Linda, and Macy
Zoey RIP 1/20/19
1999 U295 40' build #5400
2017 silver Jeep Wrangler, 1260 watts of solar on top
Moving around the country

Re: Wrong Alternator?

Reply #13 –
The Delco 36si and 40si series alternators are more money but they are brushless, more efficient, use less horsepower and generate more amps at lower RPMs and have a longer warranty. They are worth a look.  My 240 amp 40si has been working perfectly.

There are good, zero voltage drop isolators. 200 amps for under $120.

Victron Argofet Battery Isolator



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

Re: Wrong Alternator?

Reply #14 –
My alternator rebuilder(Lewco in Costa Mesa, ca.) thought the lecee Neville were ok and had large heat sinks for their diodes.

Dan does all the boat guys in the area.  Bearings and one diode out of 6 after 18 years is not too bad, 

As no alternator normally mentioned here has a battery temp sensor external regulator I would caution against using a 14.15 volt to the batteries with a combiner as in long drives in hot weather you might be overcharging the batteries by a lot.

Hot weather the auto battery temp sensor inverter/charger can go as low as 13 volts. 

Yet the high powered alternators are running over a volt more into the batteries for hours on end.

My current temp fix is to have 13.6 volts at the batteries max from both my alternator and the small solar panels we have to kerp everything up in open storage.

Wolfe here mentioned long ago the 13.6 volt input as a good compromise as we tend to have long multi hour drives versus stop and start like cars do. 

If you drive only in cold weather where the batteries as located are physically cold then the higher charging voltage can charge them faster.

I think Foretravel used the 13.6 volt charging voltage at the batteries for a longer battery life?  Lots of oem gels and alternator setups lasted 10-12 years according to the mk engineer I talked to.

My guru buddy uses an external voltage regulated alternator  and a battery temp sensor hooked to it on all bus systems

More voltage is nice at some temps but not so much in warm weather we all like?
"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: Wrong Alternator?

Reply #15 –
Certainly lots of options to optimize battery charging and maintenance.

Agree, "stupid" regulators are not ideal, but are fit on 99% of motorhomes.

"Smart" regulators are certainly not a new thing.  We have been using them to control voltage on our sailboat alternators for decades.  They take charging through the same bulk, absorption and float schedule as smart chargers and smart inverter/chargers.

Are they a good idea-- yes.  Are they required-- no.

Another option we used to protect the house bank from overcharging from the alternator is to replace the battery isolator with a simple marine ON-OFF switch.  Alternator output and chassis battery cables to one terminal, house bank to the other.  When the switch is off, chassis battery only gets charged.  When on, both banks get charged.  So, on a long drive on a hot day, starting with the house battery bank fully charged (plugged in overnight) and going to an RV park after that day's drive, I leave the switch OFF.  No point in hardtiming the house bank by overcharging it for 6+ hours.

Again, lots of choices.
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: Wrong Alternator?

Reply #16 –
We see a little over 14 volts in the morning but it quickly drops to low 13s in a few minutes. If you have a Leece-Neville alternator, just put a voltmeter on your engine batteries when they are fully charged and with a screwdriver, turn the voltage down on the alternator mounted regulator. We used Leece-Neville alternators on all of the apparatus and never had a failure in high draw emergency responses.

Our three Duralast engine batteries lasted almost 9 years so the stock setup if monitored and adjusted if not within specs, works fine. Ours needed no adjustment.

Follow the instructions here to adjust voltage. It's easy and anyone can do it.

Prestolite - Leece Neville

If you have installed an instrument panel digital voltmeter, you can accurately watch your voltages in all environments.

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

Re: Wrong Alternator?

Reply #17 –
I had not  thought enough about the easy voltage adjustability of the stock alternator.  Thanks for reminding me.  If in prolonged weather extremes the adjustment might be worth doing. 
"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4