Go Back   iRV2 Forums > MOTORHOME FORUMS > Class A Motorhome Discussions
Click Here to Login
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
 
Thread Tools Search this Thread Display Modes
 
Old 08-30-2013, 07:47 AM   #1
Senior Member
 
Spinner's Avatar
 
Join Date: Sep 2012
Location: MN
Posts: 292
Why do alternators fail?

I just had to replace my alternator this summer. Sine I've only owned the coach a year I checked the maintenance log and its been replaced 2 other times since new. I have 115,000 miles so that would mean the alternators are lasting ~40k miles or ~4 years.

I also have a couple friends who have replaced their alternators a number of times on newer coaches than mine.

On a regular car, alternators seem to last longer. Why do they fail sooner in MHs?

I've heard it could be from starting the engine while 120v is plugged in or driving on salty winter roads, but would like to hear what others have to say.
__________________

__________________
Spinner & Gang
2000 MADP ISC350 2003 Jeep Liberty toad
"Working towards the next vacation!"
Spinner is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 08-30-2013, 08:23 AM   #2
Member
 
MustangGT's Avatar
 
Join Date: May 2011
Posts: 65
I have heard that alternators often die due to their diodes burning out. 98% of the "alternator" is fine. The diodes overheat when the alternator tries to recharge a dead battery. Dead batteries are an often occurance with me...
__________________

__________________
MustangGT is offline   Reply With Quote
Old 08-30-2013, 08:53 AM   #3
Senior Member
 
Ford Super Duty Owner
Join Date: Jan 2011
Location: Lowell, Arkansas
Posts: 4,680
Inside the alternator are bearings, bushings, rotor and stator copper windings, slip rings, electronic voltage regulator and a series of diodes which convert the AC generated current into pulsating DC so it can be used by you and your batteries.

If your unit has the serpentine belt that turns everything it is adjusted by a tensioner so it can't be to tight. If you have separate belts for the alternator a belt that is to tight can wear the bearings and bushings prematurely.

Usually the windings will outlast all the other parts of the AL.

The remainder of the internal parts: electronic regulator, slip rings and bushings and the diodes are electrical devices and much depends on their quality. We the consumer will not have much control over where the manufacturer gets its parts. If it's from the lowest bidder then you can see the problem.

If you alternator goes out and you have to buy your own then you do have some control. If somebody else is replacing the alternator ask them if you can supply the alternator. When shopping for an alternator at some of your local parts houses ask them what they sell. Sometimes they will offer 2-3 or more qualities of replacement parts. The more expensive the longer the guarantee. You are getting what you pay for. In the cheaper units they will have to save where they can and that's in lower quality parts. The opposite is true for the $$$$$$ units.

I am partial to NAPA and did it for 35 years while teaching and here's why. They are nation wide and have to maintain that reputation. A lot of after market repair facilities use NAPA so they have to do a good job of supplying quality parts. They do offer several lines of parts so the smart consumer will buy the best that they offer and NAPA will honor their guarantee.

Here's one example. Go into their store and ask to buy some disc brake linings. Have them show you how many different linings they offer and their prices. I've checked in the past and a set of pads could go from $20 to $80 for the same vehicle. You get what you pay for.

TeJay
__________________
TeJay Auto Instructor/4-yrs USAF/ Liz: RN/ WBGO 2014 Vista 30T/ F-53/CHF/5-Star/Koni * Bella & Izzy * Golden /Cocker mix/ Louie The Cat* All Retired
TeJay is online now   Reply With Quote
Old 08-30-2013, 09:09 AM   #4
Senior Member
 
Beagle RC Air's Avatar
 
Join Date: Nov 2001
Location: Raymond, Washington
Posts: 414
Quote:
Originally Posted by Spinner View Post
I just had to replace my alternator this summer. Sine I've only owned the coach a year I checked the maintenance log and its been replaced 2 other times since new. I have 115,000 miles so that would mean the alternators are lasting ~40k miles or ~4 years.

I also have a couple friends who have replaced their alternators a number of times on newer coaches than mine.

On a regular car, alternators seem to last longer. Why do they fail sooner in MHs?

I've heard it could be from starting the engine while 120v is plugged in or driving on salty winter roads, but would like to hear what others have to say.
We replaced our Leece Neville alternator with a Delco Remy 28 as other have to get more charge capacity and longer life.
Replaced Alternators with ..
If you have the Leece Neville I would suggest this swap.
Beagle
__________________
Beagle RC Air is offline   Reply With Quote
Old 08-30-2013, 09:22 AM   #5
Senior Member
 
Jim_HiTek's Avatar
 
Join Date: Nov 2011
Location: Full time RV'er
Posts: 1,654
In addition, it seems that RV manufacturers don't do a very good job of allowing for ample air flow in, around, and out of the engine compartment. Coupled with a generally undersized engine for the weight of the RV causes excess heat in the compartment. Heat is the great killer of electronic components and the diodes and VR inside the ALT are susceptible.

Then there are all the reasons TeJay mentions along with another basic fact. Often the RV manuf'ers will spec an alternator that is 'just right' to quickly recharge the original battery with little headroom, to save a few bucks. When you replace yours, wouldn't hurt to spec one that has 20-40 amps more output.
__________________
'02 Winnebago Journey DL, DSDP, 36' of fun.

Visit my RV Travel & Repair Blog at : http://chaos.goblinbox.com
Jim_HiTek is offline   Reply With Quote
Old 08-30-2013, 09:24 AM   #6
Member
 
Join Date: May 2008
Location: ontario
Posts: 95
Do not know what coach you have? I had 3 alts go on my last motor home with a rear rad.Only had total about 60000 miles. This RV has a side rad seems that cures the problem, have had no failures to date, have traveled over 40000 miles.So far still has original alt. If you have a rear rad, heat seems to be what ruins the alt., Just my 2 cents worth.
rebel
__________________
rebelcarm is offline   Reply With Quote
Old 08-30-2013, 09:31 AM   #7
Senior Member
 
sc3283's Avatar
 
Join Date: Aug 2011
Posts: 1,126
large banks of batteries that often are discharged when boondocking, large inverter loads are 2 reasons also

if your batteries are down, prior to driving off, fire up the genny to recharge them...this will save major load on the alt once the coach engine is running
__________________
96 Dynasty 36' that does NOT wander, thanks to RuppParts.com and their superior "poly" suspension bushings
sc3283 is offline   Reply With Quote
Old 08-30-2013, 09:38 AM   #8
YC1
Senior Member
 
YC1's Avatar


 
Holiday Rambler Owners Club
Join Date: Jun 2011
Posts: 5,556
Quote:
Originally Posted by sc3283 View Post
large banks of batteries that often are discharged when boondocking, large inverter loads are 2 reasons also

if your batteries are down, prior to driving off, fire up the genny to recharge them...this will save major load on the alt once the coach engine is running
Here is a great answer.

My owners manual specifically recommends running the generator to charge the house batteries if they are low. The RV even keeps the battery banks isolated from each other if the generator is running and the ignition is on.(alternator running)..

I'm an ET and own an electronics repair facility. Heat will cause thermal runaway in solid state components. That is, diodes will fail due to excess heat caused by extensive current loads for long times.

Alternators are designed to refill starting batteries, not fill large banks of batteries.

Can they do it? Yes of course. Pay your money and take your chances.
__________________
Myron & Deborah
08 HR Endeavor 40 SKQ
2012 Ford Edge Limited FWD 3.5L
Aluminator tow bar, Demco base plate
YC1 is offline   Reply With Quote
Old 08-30-2013, 10:11 AM   #9
Senior Member
 
Spinner's Avatar
 
Join Date: Sep 2012
Location: MN
Posts: 292
Quote:
Originally Posted by rebelcarm View Post
Do not know what coach you have? I had 3 alts go on my last motor home with a rear rad.Only had total about 60000 miles. This RV has a side rad seems that cures the problem, have had no failures to date, have traveled over 40000 miles.So far still has original alt. If you have a rear rad, heat seems to be what ruins the alt., Just my 2 cents worth.
rebel
Sorry. Running a 2000 Newmar MADP Spartan Chassis with side radiator. 350 isc
__________________
Spinner & Gang
2000 MADP ISC350 2003 Jeep Liberty toad
"Working towards the next vacation!"
Spinner is offline   Reply With Quote
Old 08-30-2013, 10:14 AM   #10
Senior Member
 
flaggship1's Avatar


 
Fleetwood Owners Club
iRV2 No Limits Club
Join Date: Sep 2012
Location: Rainbow Riding
Posts: 18,385
Quote:
Originally Posted by Spinner

Sorry. Running a 2000 Newmar MADP Spartan Chassis with side radiator. 350 isc
Maybe it was the difference in paint job and not the location of the radiator.
__________________
Steve & Annie (RVM2)
2008 Fleetwood Bounder 38F ~ 325 ISB Turbo ~ Freightliner XC 2014 CR-V ~ Invisibrake / Sterling All Terrain
Sioux Falls, SD (FullTime Since Nov 5th 2014)
flaggship1 is offline   Reply With Quote
Old 08-30-2013, 10:27 AM   #11
Senior Member
 
Spinner's Avatar
 
Join Date: Sep 2012
Location: MN
Posts: 292
Quote:
Originally Posted by flaggship1 View Post

Maybe it was the difference in paint job and not the location of the radiator.
Hmmm. I do need to get my coach painted. I bet that will solve it. 💡
__________________
Spinner & Gang
2000 MADP ISC350 2003 Jeep Liberty toad
"Working towards the next vacation!"
Spinner is offline   Reply With Quote
Old 08-30-2013, 10:45 AM   #12
Senior Member
 
CampDaven's Avatar


 
Join Date: Jul 2012
Location: Fulltime, USA
Posts: 14,447
Blog Entries: 1
Quote:
Originally Posted by sc3283 View Post
large banks of batteries that often are discharged when boondocking, large inverter loads are 2 reasons also

if your batteries are down, prior to driving off, fire up the genny to recharge them...this will save major load on the alt once the coach engine is running
Yep.

Every alternator failure I ever had coincided with bad batteries. The diodes fry.

I began strict battery maintenance and have not subjected them to large loads (ie: discharged bank). No troubles since.
__________________
Dave and Nola, RVM1
The Journey is Our Destination!

http://davenola.blogspot.com/
CampDaven is online now   Reply With Quote
Old 08-30-2013, 10:57 AM   #13
Senior Member
 
wa8yxm's Avatar
 
Damon Owners Club
Workhorse Chassis Owner
Join Date: Mar 2009
Posts: 22,787
There are 3 reasons that alternators die (Well 4 but one is obvious)

1: Overload.. Though they are supposed to be self regulating when it comes to current. fact is it is possible to overload 'em.. These folks who put residential fridges in their RV's often have this problem. But the fact is.. RV's can suck a lot of 12 volt, Solution... A MUCH LARGER ALTERNATOR.

Second. HEAT. many body builders are not good at managing air flow around the engine, this has led to many issues epically with the Workhorse chassis and the 8.1L engine,, it is the body builder at fault, though Workhorse sells the fix it kit, Burns up spark plug wires.. Burns up alternators too.

#3 is voltage spikes.. Such as happen when you jump start someone (Last time I jumpstarted with the motor home we cheated like blazes... (Fired up ye-old-onan and used the jump start-battery charger I carry in my basement.. NOT the motor home batteries but a transformer and diodes designed for the job)

The 4th one (Obvious one) Bearing failure.

NOE that heavy loads wear out the brushes as well as heat up the diodes.
__________________
Home is where I park it!
wa8yxm is offline   Reply With Quote
Old 08-30-2013, 11:00 AM   #14
Senior Member
 
Arizona's Avatar
 
Join Date: Aug 2013
Posts: 350
The electronic part is what goes out. If you can still get external regulators you can replace that for less than$20. My first class a had one (86 chieftain). They don't make them that way anymore for the same reason you need to buy the whole windshield wiper instead of just what you need, the wiper blade.
__________________

__________________
Arizona is offline   Reply With Quote
Reply



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Virginia Campgrounds

Reviews provided by


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 05:55 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.