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Alternator

Yahoo Message Number: 68323
My start battery is not getting enough voltage, 12.1 - 12.2 volts while running.
Any suggestions besides the alternator? I ask because I have a shop that will take it out and bring it to an expert. His opinion on the phone was that it probably wasn't the alternator because they are heavy duty and should last for 100's of thousands miles.

Thanks
John

2007 Inspire 52028 Cummins 400 ISL 46,000 miles

Re: Alternator

Reply #1 –
Yahoo Message Number: 68324
The alternators have a weak regulator. Probably your problem, but it has to be pulled to work on it. Easy to check with a voltmeter reading at the battery wire at the alternator to be sure it is the problem.

Leonard

97' Magan 5418

Re: Alternator

Reply #2 –
Yahoo Message Number: 68327
To step back a bit, what is/are the problem/symptoms? Poorly charging coach battery? I can't tell if I should suggest that you look at the echo charger or not.....

Denis Vogel

'06 Allure #31409

Re: Alternator

Reply #3 –
Yahoo Message Number: 68328
John,

I've got 38,000 miles on my 00 Affinity and I had to have my alternator rebuilt last year. I pulled it out myself and when I did there was a rebuild sticker already on the alternator. So apparently it has been rebuilt twice. I know my coach is a low usage coach therefore I believe the alternator was probably overworked. If you let the batteries get to low (House and Chassis) the batteries can take more amperage than the alternator can output to charge them for an extended period of time. Operating the alternator at max. output for a extended period of time causes them to get extremely hot. Remember, when it's running it's also charging the House batteries. I'll agree they should last a long time if used properly but If it is put in extreme conditions it can fail at anytime. Although anything manufactured can have a defect that can cause it to fail prematurely on it's own.
Bottom line, If your alternator is not outputting more voltage that 12.1-12.2 volts, it is bad.
Kevin Burns

00 Affinity 5865

Re: Alternator

Reply #4 –
Yahoo Message Number: 68330
Quote
Quote from: Johns RV"
John,

76,000 miles on on Intrigue and I am on my third alternator. Ask your friend where he gets those 100,000 mile alternators.
Lyle Wetherholt
04 Intrigue 11740
> My start battery is not getting enough voltage, 12.1 - 12.2 volts while > running.

> Any suggestions besides the alternator? I ask because I have a shop that > will take it out and bring it to an expert. His opinion on the phone was > that it probably wasn't the alternator because they are heavy duty and > should last for 100's of thousands miles.

Thanks

John

2007 Inspire 52028 Cummins 400 ISL 46,000 miles >

Re: Alternator

Reply #5 –
Yahoo Message Number: 68331
Ol' '99Magna has 94K+ miles... Still crusing along on the original alternator...

buck

k7wn, '99magna5653, Cat C10, Allison HD4060

=====================================================

Re: Alternator

Reply #6 –
Yahoo Message Number: 68332
56,000 miles on '05 Intrigue and I am on my third alternator as well.

Brian Davis

05 Intrigue 11901

Re: Alternator

Reply #7 –
Yahoo Message Number: 68333
We lost an alternator at 22K miles. Ours was obvious as there was smoke coming from it. The CAT mechanic who replaced the alternator said that alternators are built for trucks with the pulley end forward. Ours are mounted with the pulley end facing the rear so the suck up more crud.

Bob

'05 Intrigue 11872 with CAT

Re: Alternator

Reply #8 –
Yahoo Message Number: 68334
I am also on my third alternator in my 1997 with 120,000 miles.
The third one I upgraded form 160 amp to 200 amp.
It has been about a year now, and is working well.

Bob Wexler
SOB

Re: Alternator

Reply #9 –
Yahoo Message Number: 68335
Dennis,

John stated that while running it has low voltage. The echo charge is not in play at that point. However if the echo charger is not working and allowing the chassis batts to discharge it could be the underlying cause of the alternator failure.
Kevin Burns

00 Affinity 5865

Re: Alternator

Reply #10 –
Yahoo Message Number: 68345
I assume the connections at the alternator, battery isolator and at the battery positive and ground have been removed, cleaned and tightened? Those steps made a difference for me at one time.

Dean

95 Magna 5280

Re: Alternator

Reply #11 –
Yahoo Message Number: 68361
The owner's manual has a very detailed trouble shooting section for the alternator. When mine failed, I found a new alternator was only a few dollars more than having mine rebuilt.

Greg Jones

'03 Intrigue 11571

Re: Alternator

Reply #12 –
Yahoo Message Number: 68363
I had the same problem. Ran a continuity test from alt to battery and found badly corroded wires. Larry R
#11991

Re: Alternator

Reply #13 –
Yahoo Message Number: 68365
Thanks for all the suggestions. As a result I am having the alternator pulled next week and bench tested then rebuilt if necessary.
John

Re: Alternator

Reply #14 –
Yahoo Message Number: 68369
John-

Motorhomes that charge both starting & coach batteries represent a particularly difficult challenge to an alternator. The more times an owner starts up w/heavily discharged house batteries (usually a large battery bank), the more times the alternator is subjected to very heavy amp demand. The regulator package (contains diodes, etc.) within the alternator both generates heat & is subjected to heat from the windings. Eventually you cook the regulator and the alternator won't charge properly (you can also cook windings, and rebuilders can attend to this as well as burnt regulator). This is different than a truck, where the starting batteries are the only usual charging draw (except specialty trucks that have 12V powered gear, but I digress).
The caveat about checking connections (at alternator and at batteries) is important; also check for slipping belt which is unlikely but possible, however your tech saying its probably not the alternator because its "heavy duty" isn't a clever diagnosis, and I'd be wary of advice from somebody who starts w/that posture. Any moron w/a good tester can easily hook up & test alternator output (I know cuz I've got the tester, have done it, and I'm certainly the equal of any moron), and the test takes maybe 20 minutes on most coaches mostly because connections are obscured. because of that ease of testing, I'd say #1- check connections, run, check voltage; #2- test alternator @ the alternator. If its the alternator & you get yours rebuilt (there are rebuilders in most large-ish towns), have them mount the new diode (regulator) package outside the case for better heat dissipation. Your rig is somewhat young to be cooking alternators, and this trick (taught by an old-timey rebuilder) should help future longevity. They mount the regulator inside as it makes for a one-piece deliverable package, but the interior location has no magic to it, and where heat is an issue the exterior mount is superior.
Her is a link for further info (cars, not truck, but still very applicable): http://www.aa1car.com/library/charging_checks.htm Mike

Re: Alternator

Reply #15 –
Yahoo Message Number: 68370
Mike,

Can you give more information on the external mount. Like the ideal a lot. How and were can one get the parts, etc?

Leonard

97' Magna 5418

Other thoughts. Have seen plenty of truck size alternator failures. They are big because they have to put out big. Heavy Duty is not a correct description to me. Heaver duty then what? Our first gas rig had a single 8d for everything, no gen., simple days. I would burn out an alternator about every two to three years. Simple worked itself to death re-charging that 8D on the way home each trip.

Re: Alternator

Reply #16 –
Yahoo Message Number: 68374
Mike,

Very good response. I have dealt with similar problems on boats and yes a remote regulator is a big improvement.
Here is a link for just one good source. http://www.balmar.net/
John

05 Inspire #51399
10 Ford Escape

Re: Alternator

Reply #17 –
Yahoo Message Number: 68383
Good point Bob, Ken Retired Cat Tech! Worse in Boats/Pleasure Craft. Thanks for sharing, BTW we are Tech's! Ken 99 Allure 30356.

Re: Alternator

Reply #18 –
Yahoo Message Number: 68388
Leo- looking back at my post I didn't word that quite correctly, tho it gave the idea. The diodes are what typically create a lot of heat in addition to the windings. The outside mount of diode packs has been done on alternators for several Alpine Coach owners whose alternators quit due to overwork. This happened on 160A alternators after going from 6-U220 batteries to 8; my theory was the aded potential for heavy draw from the 1/3 extra battery capacity is what killed the 160A units early. Some went to 200A alternators, some has a 160A unit rebuilt to a "200A" standard (got no idea how this works), and some had the diodes relocated during rebuild. This is only possible if rebuilding. No package rebuilders or OEM alternators come this way to my knowledge.
Because the moho alternator is a "heavy duty" type on an assembled vehicle (vehicle made of off-shelf parts as opposed to full-custom-designed vehicles like modern cars), they come w/integral regulator which today is probably solid state (many cars have volt regulation handled in the ECU these days w/none in the alternator itself). Breakdowns can come from burnt out regulator, diodes, or winding failures, or burnt up bearing usually on the pulley end which sees highest constant forces. This diode trick was specified by the old, wrinkled rebuilder, which made good sense to me. Not sure how he fastened the pack to the case, but it couldn't be too tough to do. The diode pack usually comes w/an integral heat sink, which I'd consider augmenting if I was doing this; any CPU heat sink, some heat transfer paste, & a good mechanical connection to increase the surface area of heat dissipation would be fun IMHO. If you wanted to DIY this, I'd go to a local rebuilder w/your alternator part# to purchase the diode pack (might as well start w/a new pack if you're going thru the exercise), and maybe install a new regulator while up to your elbows in this project.
Google: "alternator diode" and you'll find great info on diagnosis of alternator problems.
Here is an interesting outfit for the DIY'er: http://www.aspwholesale.com/ and you'll find others searching "alternator parts" and "truck alternators" Mike

Quote from: Leonard Kerns

Re: Alternator

Reply #19 –
Yahoo Message Number: 68399
Comment

A good rebuilder can produce a product as good or better than new because they will use better quality products. They can also boost the output. I have run a unit boosted from 65 to 100 amps on my jeep and 160 to 200 amp on motorhome for years. Can't explain how they do it but my guy does it routinely for fire and police departments, snow plow operators, and kids with big stereos, anyone with heavy amperage requirements.

Dan 2006 Allure 31348

Re: Alternator

Reply #20 –
Yahoo Message Number: 68425
Diode DC Voltage drop causes heat. The more currant and time through a diode and a weak heat sink Failure will occur. I have seen rebuilt alternators from NAPA and Cat Rebuilds in our fleet trucks with a under charged battery's, Seen the solder melting off the pig tail side of heat sink mounted diodes. Yes under charged! and large banks od batterys! will lessen the life of Battery Charging Alternator's. Most of the time I replaced Battery's with the Alternator but I used Cat Money for this as a Tech. A fleet truck down cost a lot more money! Do the math. Their are Alternators that are REALLY SUPER DUTY but they are way too expensive! These type of Alternators are seald and have massave heat sinks on them. They are used on engines in the oil industry ware Flammable gas etc. A spark from a open Alternator brush rigging can Ignite a Blast. I enjoy you posts. FYI Ken in Yuma. 99 Allure 33056

Re: Alternator

Reply #21 –
Yahoo Message Number: 68436
Ken

I would assume you have looked inside the back of a NAPA and a heavy duty alternator and seen the difference in construction.

Dan 2006 Allure 31348
 

Alternator

Reply #22 –
Yahoo Message Number: 91958
Been a while I posted on this group. Sent out our 14 year old Lece Niville 14 volt 160 amp. Alternator for rebuilding. I see we have a new Yahoo Format. When I pulled it out of the coach could feel the Bearings starting to fail. Just a heads up us older Coach users have you Alternator serviced before its too late! Ken 99 Allure 30356.