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Alternator alternatives

On the way back from Nacogdoches I noticed my voltage fluctuating.  After a stop, upon crankup I found I had no response from transmission shifter.  After a mild panic attack, I shut the engine down, cranked the genset, flipped the boost and all was well but I knew I was now due for alternator repair.  This began a period of intense research, I hope this info will help anyone else faced with this issue. 

After pulling the old one off, I noted the bearings were rough and the body looked like it'd been through a war.  I did also notice it was plastered with DUVAC stickers, requiring a specific alternator.  I really didn't want to deal with a rebuild shop, decided brand new was the way to go.  Since so many folks have complained about the short life of these alternators, I started seeking alternatives.  Here's what I found....

The Duvac alternator has four terminals, a + output that goes to the center of the isolator, a - that goes to ground, a remote sense wire that goes, essentially, from batteries to alternator so it can sample voltage after the voltage drop from the isolator, and a remote turn on wire (ignition excite).  While you can obtain these DUVAC alternators for a premium price, I wanted to see what else was available.  After several conversations with Leece Neville tech service, all pretty inconclusive, I decided to plow ahead with a newer model alternator with next generation regulator.  This was not a Duvac , and as it turns out with the newer alternators, Duvac is not, in fact, required, you only need the remote sensing function.  Newer alternators are excited from the AC terminals on them, it is not necessary to supply a votage to "turn them on"  they self excite once they start to spin.  The fact that the + output is not hot due to being tied to the isolator does not matter with this style alternator.  This issue has tripped up quite a few motorhomers and repair shops. 

Here's the alternator I installed.  Cummings 3675161 Alternator 2800 LC Leece Neville Bus | eBay  This is a 160 amp Leece Neville, cost was $170.00.  It appears to be the genuine article, brand new in factory packaging and not a knock-off.  There are plenty of them around and you don't want one (knock off).  An example of a knock off alt is a World Power Systems distributed "genuine" Leece Neville.

You will notice it includes the upgraded regulator 103450 instead of the 102200 reg that was standard when the coach was built.
Next order of business is to configure remote voltage sensing.  For this you need to unbolt the regulator, , disconnect the small red wire from the regulator, cut and insulate the end of the red wire.  It will not be used.  At the point on the regulator where the red wire was bolted, a new wire is attached.  You can either drill a hole in the bakelite brush housing to mount a stud to tie it to as I did, or drill a hole in the rubber grommet above where the two yellow wires pass through to go to the ac taps.  Ultimately, this wire will tie to the remote sense wire on your harness.  If I was doing it again I would forego the stud (it has to be precisely drilled so as not to interfere with the regulator or brushes) and there's no reason a  wire can't be run a few inches out of the housing, have a ring terminal installed, and bolt the harness wire to it.  At this point you need to reinstall and pin the brushes, reattach the regulator, and remove the brush pin.  Barry Beam has kindly provided a nice link for this operation: 

Alternator Brush inspection and replacement  Skip down to item #4 which shows how the brushes are reinstalled.  It' quite simple.

Then the alternator is reinstalled.  Before replacing it, take your meter and check harness for voltage.  Only one small wire should be hot when the key is off, this is your remote sense wire that will tie to your new regulator lead.  Turn the key on.  Now the other small wire should be hot.  This wire will not be used, it's the old ignition excite wire.  Leave it in place and insulate the end, do not connect it to anything.  Bolt up your large + output and your - ground, connect your remote sense wire to new stud or ring terminal,  reinstall belt and you're ready to roll.  My voltmeter shows 14 at idle volts which seems about right. 

There is another alternative that does not require modifying anything at all, and gives you a much higher quality, and probably more durable alternator.  That is to use one of the new Leece Neville brushless alternators.  They can be connected one, two, three or four wire configuration on any of them, which covers any possible installation.  In addition they are designed for much higher temp operation for newer vehicles with high underhood temps. In addition, they have heavier fans, 12 instead of 6 diodes and are considered to be bulletproof.  My guess is that you can, with no worries, recharge your house bank with one of these.  While I was sorely tempted, the cost was more than double what mine cost and baby needs shoes. 

A couple words of warning.  Modifying your new alternator will void your warranty even though Leece Neville will advise you  how to modify it.  You may also run into Tech Article #45 from L.N.  which covers modifying an older alternator such as a 2800JB for Duvac. This tech article does not apply to the newer alternator! My instructions are for a 2800LC, which is the next gen above 2800JB (no longer made and considered obsolete though there are some still out there.)  You can readily tell the difference, the newer one has an additional pair of yellow leads which bolt to two of the three AC taps on the back of the alt.  In addition it has a 103450 regulator instead of the old 102200.

I did put a call into Foretravel but was told the only alternator which would work was a direct replacement for the original at +$500.  In fairness, that would be a direct bolt in replacement.  I was also cautioned by Leece to be sure my replacement alternator has the same number of poles as the old, otherwise the tach will not read correctly.  As it turns out, the tach reads directly off a flywheel sensor so that's a non issue on the C8.3. 

I'll be glad to share whatever I know on this issue, feel free to ask. 



Re: Alternator alternatives

Reply #1 –
Very good info....In the past 2 years I've pulled mine out twice for rebuild, I wonder if I should try this next time. Last time it died the dash volt meter would swing from 10.5 to 13 volts and at night you could see the flicker in the head lights

Re: Alternator alternatives

Reply #2 –
Great info Chuck. From your write-up I now know why the external excite is needed. . . because the high amp output being connected to the isolator never sees battery voltage, which is need to initially power the rotor windings.  How clear.

Do you know if the voltage regulator is adjustable?

I am aware of the regulator that has 3 small internal screws to move 2 metal jumpers to select low, med or high voltages.

I am also aware of the regulator that has an external rotational adjustment to change output voltage infinitely within a narrow range. We are now using this and have lowered alternator output voltage for hot weather to better conform to the MK GEL battery charging temperature chart.

Do you know if the new brushless alternator comes with choice of regulator and if it is adjustable?

Because isolators lower output charging voltages, alternators need to put out a higher voltage. But because our pressure sealed AGM & GEL batteries cannot normally breathe, charging voltages must not be too high to prevent gassing. So our alternator output must fit into a narrow voltage range to keep from damaging batteries, yet still provide a good charge. Another reason to not use alternators to charge low house batteries.

Re: Alternator alternatives

Reply #3 –
Barry and Cindy, 

Thanks, I put an inordinate amount of time into figuring out what turned out to be a rather simple problem.  It is, however, readily apparent that Leece Neville was originally a British corporation, and their tech literature is both beautifully illustrated and astoundingly contradictory. 

One thing, though, the external excite is not used with these newer alts., the remote sense is  what you need.  This mitigates the problem of the voltage drop through your isolator, without it your voltage output would be unacceptably low. The alternator takes care of turning on and off (external excite) on its own when it starts to spin.  To answer your questions:

No, the 1034350 regulator is not adjustable.  It's called a 14.2 volt regulator which I assume is the max output.  The old 102200 alternator did have a movable mini bus bar in it.  IIRC it allowed for a max of 14V output. 

I don't know about the regulators on the brushless units.  What I do know, though, is that if you are really looking for total management of your charging cycles, there is a good alternative that will work with almost any of the Leece high output alternators.  That is an external multi stage regulator.  This takes the output of your alternator and manages it exactly like your onboard inverter/charger.  It turns your alternator into a 3-5 stage smart charger with charge profiles fit to your battery type.  Not too expensive, in the 250.00 range for the regulator only.  Heart makes one, but Balmar is considered the best.  Balmar Voltage Regulators  These are marine duty components with a good rep for durability. 

Almost any of the alternators can be set up for an external regulator.  With the Balmar or equivalent, and the brushless alt, you'd have the state of the art as we know it.  I found the brushless alts in the 450.00 range.  I'd love to see someone set up a rig like this, let me know if I can help.  Of course you could also use a brush type alt such as I installed, reconfiguring it for an external regulator and save some $.  Probably forget about hiring it done, tho, this will need to be diy. 

Chuck



Re: Alternator alternatives

Reply #4 –
Excellent article and makes complete sense. Even though my alternator went toes-up a month ago (or more) I haven't replaced it because I dislike laying on rain-soaked cement in 50-degree weather. But now that the weather has improved I'm going to remove it and put it on a test bench and see what's up.

I don't think I'm going to plow $500 into a brushless version though. Or buy an external regulator (I used a potentiometer on my sailboat back in the 1980s). At least not right now. But I certainly do appreciate all the work you have done and the clear presentation.

Thanks!!

Craig

Re: Alternator alternatives

Reply #5 –
Craig, I think your coach is one I was looking at on line. I had several phone calls with the old owner if it the same unit. He was replacing or repairing the alternator at the time. I wonder if there is a warranty on yours? If it is the same one I think the guy was an electrician.

Re: Alternator alternatives

Reply #6 –
Chuck,

You have increased my alternator knowledge a lot and I appreciate it.

If you have an email contact at Prestolite Technical Support, could you email it directly to me at Foretraveler@gmail.com?

When I replaced all the breakers, relays & solenoids on our isolator panel last year, I ran a new remote voltage sense wire through a circuit breaker to start battery positive terminal, bypassing the original connection at the isolator panel.

Does the alternator voltage regulator remote sense try to charge the start battery at about 14.2 volts? If so, the alternator would have to increase its output voltage to around 15 volts because of the isolator voltage drop. And 14.2 would be too high for a warm/hot AGM & GEL.

Otherwise it seems to me that a fixed voltage regulator at 14.2 might work ok as the diode isolator would drop voltage to about 13.5 volts which could be a satisfactory general charge voltage at all battery temps. And if a system did not use an isolator, and used flooded batteries, 14.2 volts would still be ok.

When we rebuilt our alternator last year at an 'old-time' small shop, I asked for an adjustable regulator, which so far has worked ok, but it is awkward to adjust.

I like the self-excite idea of the new alternators and I assume they don't drain current when off.

While the brushless units look inviting, I wonder about switching due to unknowns.

Thanks for the Balmar source, but I don't think we need to use a 3-stage regulator for engine start battery. I like what I see with Balmar, but it is not needed since we have a generator and highly adjustable Prosine 2.0 charger.

Our Prosine is responsible to keep our house & start battery banks full without over charging. And consider our 730 solar watts and engine alternator charging sources to be secondary so I have the set them to charge about 13.3 volts in warm weather. We do have a smart voltage-controlled relay-based house & start combiner that charges our start battery at the same voltage as our house battery.

We are on our 2nd rebuild of our original alternator in 12-years where each time almost everything is replaced, so maybe a new unit would be practicable if I could figure out new voltage regulator options. Both times we were lucky to find one of those old-timers who can replace parts with their eyes closed. And the one time our alternator stopped alternating, we still could drive with generator & boost on until we found the 'right' place to have it rebuilt.

Thanks for your offer of assistance, Chuck. Barry

Re: Alternator alternatives

Reply #7 –
A couple years ago I was stranded in an AR CG with a burnt out Powerline Alternator. While waiting for FED EX I found a local shop and explained what I had. After some study the guy BUILT me a DELCO Externally excited alternator.  It puts out only about 120 AMPS but it is still in my bay as a standby.  New alternator that I installed is a 190 Leece Neville and it has been trouble free.  I can't complain, original went 14 years before death..
Gary B

Re: Alternator alternatives

Reply #8 –
Chuck,
Thank you for the detailed description of the alternator install.  As they say in certain circles..."you da mon".  Now, as I am not really very well versed in electrical stuff, this has me starring at the ceiling with a blank look...

Quote
The fact that the + output is not hot due to being tied to the isolator does not matter with this style alternator.  This issue has tripped up quite a few motorhomers and repair shops. 

Can you explain where you are reading the "not hot" condition?

Thanks again,
Peter

Re: Alternator alternatives

Reply #9 –
Quote from: philtravel –
Craig, I think your coach is one I was looking at on line. I had several phone calls with the old owner if it the same unit. He was replacing or repairing the alternator at the time. I wonder if there is a warranty on yours? If it is the same one I think the guy was an electrician.

Phil... the guy who sold me my coach was an electrician and lived on Camano Island north of Seattle. If it's the same guy I should give him a call. The alternator actually looks pretty new but I haven't found any receipts in the box where there were lot of them. Do you remember where he was located?

Craig

Re: Alternator alternatives

Reply #10 –
I think that was him. I recognized your original picture that he used when he was selling it. It looked like a nice coach but we decided to get something a little newer and I wanted a larger engine.

Re: Alternator alternatives

Reply #11 –
My alternator went on my trip out west two summers ago in Pensacola.  The manager at the park we were in sent us to Empire Freightliner.  They replaced it with a Delco 28SI 160 amp Hi output alternator for $273.37 plus labor.  Unfortunately they didn't wire it properly and we broke down in Jackson just passing another Empire Freightliner.  They thought it was defective and we lost a day waiting on a replacement, which once installed did not charge.  Gary asked if they knew that this alternator must be externally excited.  Once I mentioned this, one of the more experienced hands came over with his mirror and put a jumper on two of the posts which did the trick.  This looks like the one:  Delco and Leece Neville High Output Alternators  Been working great since.  This board is invaluable. 

Re: Alternator alternatives

Reply #12 –
Sorry to be so long in responding, I've been in the boonies and away from net access. 

Quote from: Barry & Cindy –
Chuck,

If you have an email contact at Prestolite Technical Support, could you email it directly to me at Foretraveler@gmail.com?

When I replaced all the breakers, relays & solenoids on our isolator panel last year, I ran a new remote voltage sense wire through a circuit breaker to start battery positive terminal, bypassing the original connection at the isolator panel.

Does the alternator voltage regulator remote sense try to charge the start battery at about 14.2 volts? If so, the alternator would have to increase its output voltage to around 15 volts because of the isolator voltage drop. And 14.2 would be too high for a warm/hot AGM & GEL.

Otherwise it seems to me that a fixed voltage regulator at 14.2 might work ok as the diode isolator would drop voltage to about 13.5 volts which could be a satisfactory general charge voltage at all battery temps. And if a system did not use an isolator, and used flooded batteries, 14.2 volts would still be ok.

When we rebuilt our alternator last year at an 'old-time' small shop, I asked for an adjustable regulator, which so far has worked ok, but it is awkward to adjust.

I like the self-excite idea of the new alternators and I assume they don't drain current when off.

While the brushless units look inviting, I wonder about switching due to unknowns.

Thanks for the Balmar source, but I don't think we need to use a 3-stage regulator for engine start battery. I like what I see with Balmar, but it is not needed since we have a generator and highly adjustable Prosine 2.0 charger.

Our Prosine is responsible to keep our house & start battery banks full without over charging. And consider our 730 solar watts and engine alternator charging sources to be secondary so I have the set them to charge about 13.3 volts in warm weather. We do have a smart voltage-controlled relay-based house & start combiner that charges our start battery at the same voltage as our house battery.

Nice setup, one I would like to duplicate. 

We are on our 2nd rebuild of our original alternator in 12-years where each time almost everything is replaced, so maybe a new unit would be practicable if I could figure out new voltage regulator options. Both times we were lucky to find one of those old-timers who can replace parts with their eyes closed. And the one time our alternator stopped alternating, we still could drive with generator & boost on until we found the 'right' place to have it rebuilt.



Thanks for your offer of assistance, Chuck. Barry

I posted my questions on the support forum and got some basic answers.  Alternators | Prestolite News  I also called their tech support line, spoke with Marsha, and she got right to the point.

Yes, the way the remote sense is connected in my coach, original configuration, it is on the output side of the isolator, essentially tied directly to battery.  So, the alternator is outputting in the 15 volt range with a .7 volt voltage drop thru the isolator.  If this is too high I would think you could move your voltage sense to the input side of the isolator and your voltage to battery would be 13.5 after isolator drop.  I have not tried that so some others may have knowledge of how it would work.

You might give a call to Prestolite.  I am reasonably certain you can install the old style adjustable regulator on the new self excited alternator.  The old style regs are readily available new and are inexpensive.  That would give you the same thing as you have now but a new alternator rather than rebuilt, along with their heavier bearings and other improvements.  The Ebay price for the new alt is compelling also, less than a rebuild.


Quote from: Peter & Beth –

Can you explain where you are reading the "not hot" condition?

Thanks again,
Peter


When the ignition is turned on, one of the small wires going to alternator goes hot.  This is your remote turn on wire.  The other small wire is your voltage sense wire, it stays hot key on or off. 


Quote from: Barry & Cindy –

Because isolators lower output charging voltages, alternators need to put out a higher voltage. But because our pressure sealed AGM & GEL batteries cannot normally breathe, charging voltages must not be too high to prevent gassing. So our alternator output must fit into a narrow voltage range to keep from damaging batteries, yet still provide a good charge. Another reason to not use alternators to charge low house batteries.

Good point.  I haven't taken the time to look up the profiles for my red top start batteries and it could be I'm killing them with over voltage.  One of those situations where I absolutely had to bolt her up and go.  When I get a bit of time I'm going to look at this and also consider building a controllable voltage input for the voltage sense, kind of a po boy adjustable regulator. 

Chuck

Re: Alternator alternatives

Reply #13 –
Thanks Chuck for your reply and a way to get to Prestolite for Leece Neville questions.
Barry

Re: Alternator alternatives

Reply #14 –
Has or 'is' anyone running an alternator large enough to power 1 roof top air conditioner-- rather than using the fuel guzzling diesel generator?  there are some 275 amp Alternators, (large case) models with I think... the ability for external regulators that might do the job. 

Re: Alternator alternatives

Reply #15 –
What would the alternator be powered by? The onboard diesel generator is pretty thrifty at part load. A smaller diesel would have to run at a higher load with a lower numerical air/fuel ratio. The fuel savings might be only 10 or 15 percent over the main unit.

Pierce

Re: Alternator alternatives

Reply #16 –
Pierce,

Would not a huge alternator on the drive engine not be the simple solution?  There must be some sort of 120 volt huge upgrade things that could be hung on the main somewhere.

I just had a flash back to my early bike days, and a generator swinging down to touch on my bike wheel spinning like crazy down the hills, to power the headlight and taillight. 

Re: Alternator alternatives

Reply #17 –
A larger engine will always have higher parasitic internal friction than a smaller engine so would use more fuel than the house generator. In this case, the main 5.9 engine would displace somewhere abound three times what the house generator would. Difficult to control main engine speed, difficult to run the proper drive belts for the alternator. Prolonged idle is bad for big diesels, especially the 2 cycle Detroits. Would put a lot of hours on the main engine with oil changes about 3 times more expensive than generator. Main engine would really heat up cabin bed on hot summer nights after main turned off.  Could go on but think the factory diesel generators work well with a minimum of trouble.

Pierce

Re: Alternator alternatives

Reply #18 –
Was thinking you missed the "not run the generator, and use the main as you cruise down the highway".  I think that Ron was suggesting day time driving run time.  I guess to add to the dash air not doing the job.

Re: Alternator alternatives

Reply #19 –
Yes, missed that part. Even with both engines running, I still think the house generator is the best and cheapest way to do it. An added load to the main engine would mean additional fuel used also. Just like driving a car with the windows down or windows up with the air on. The air really drops the mpg.

Pierce