M1078 Alternator Problem

[Faial]

i know this is an old post, but maybee my info will help others. if anyone has tried to replace a niehoff dual voltage alternator for an lmtv you know two things they are extremely expensive, unreliable, and difficult to find. i recently had the alternator on my m1078 fail, and its only 3 years old. we are currently in the final stages of completion of a dual voltage alternator which utilizes off the shelf repair parts. units will be available with a filtration system, and are made in america.

 

[Adventure Driven]

this sounds great. keep us posted

Seth

 

[Suprman]

I have found the alternators to be very reliable. Most of the time its the truck wiring and you loose the 24v to the regulator, which is used to excite it. No 24v to excite the alt will just spin and make no power.

 

[scottmandu]

The Neihoff alternator used in the LMTV is light years ahead of any other automotive type alternator, regarding reliability. It's an induction type alternator which means no brushes to wear out and it also can operate submerged. Parts are also readily available if you know where to look.

 

[Suprman]

I find the regulator confuses people. The front terminal is 24v excite/regulation and the back terminal marked AC is actually an AC output. Can be used to drive a tach and some other stuff. No idea what it's connected to on the first gen trucks.

 

[1951M1078]

Suprman do you have a photo of the A?C out on the back ? Just want to check for when I install my tack.
Thanks, Randy

P.S. you every get a chance to check for the oil tube ?

 

[Faial]

We have three lmtvs all with bad alternators. Two of the m1078s have had them replaced in the last three years. I have sent two of them to neihoff authorized service centers and the parts that have failed are sealed in epoxy meaning can't be serviced. Spoke with neihoff directly. Any alternators or parts have to be purchased through a distributor and must have clearance from d.o.d. which takes 18 to 22 weeks. This is what I was told by neihoff. Honestly I wouldn't want to be on a trip with this truck and have an alternator failure again. Not worth the headache. I sleep easier knowing Napa will have repair parts. Regardless, for those interested i will post the information aboutbthe company im workimg with and pictures as soon as I have the aftermarket unit installed. Unit will be a direct bolt on with filtration. And you will not need the charge controller located by the spare tire.

 

[Suprman]

An easier way would be to change over to a straight 24 volt alternator. Something in the 120-150a range. Use a 100a battery equalizer power converter for the 12v. Add in a battery disconnect like the newer A1 trucks have. Box under the spare tire is only there to protect against improper battery installation on first gen trucks. Newer A1s have the advanced box that is supposed to regulate battery charging.

 

[Faial]

I see what your saying and I thought about that, but less parts the better. Keep it simple all contained in one unit plus filtration for less than half the cost of a neihoff. Will see what happens. Thanks for all the input.

 

[xomegaiv]

I see what your saying and I thought about that, but less parts the better. Keep it simple all contained in one unit plus filtration for less than half the cost of a neihoff. Will see what happens. Thanks for all the input.

Faial I am super interested in you mod. Please keep us posted.


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[Wile E. Coyote]

What seems to cook the OEM ones is everyone's (GovPlanet among them) bad habit of just slave-starting vehicles fitted with absolutely ancient, frozen, worthless batteries - older and deader than the Pharoahs - and letting the alternator sit there going full bore trying to charge the unchargeable. When I've had them here along with the description, "starts with a jump", each battery has at least two or more shorted cells, so you're giving the charging system a 14-16 VDC/ 6-8 VDC load for the 28 VDC/ 14 VDC alternator output. It isn't clever. Like charging a 12V battery on the 24V setting on your shop charger.

 

[thetruckguy]

i know this is an old post, but maybee my info will help others. if anyone has tried to replace a niehoff dual voltage alternator for an lmtv you know two things they are extremely expensive, unreliable, and difficult to find. i recently had the alternator on my m1078 fail, and its only 3 years old. we are currently in the final stages of completion of a dual voltage alternator which utilizes off the shelf repair parts. units will be available with a filtration system, and are made in america.

I am very interested! Do you have any available yet?

 

[xomegaiv]

I am very interested! Do you have any available yet?

Contact Ron at http://double-alt.com

I will be installing mine here soon. I'll let you know how it does.



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[Levelox]

.

 

[Couchoffroad]

Any luck with your hybrid alternator?
Thanks

 

[xomegaiv]

Any luck with your hybrid alternator?
Thanks

Works flawlessly. The only regret is not finding Ron from double alternator any sooner. I bought a replacement original and it didn't last either. If you are having problems with your FMTV alternator the double alternator from Ron is the way to go. It's built with off the shelf parts so it's easy to repair if need be.


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[dalej]

97 lmtv alternator

So, just sorted my problem out. Jumpering the 'E' terminal on the alternator to +24V made it all work, which meant no exciter feed to the alternator. I looked for the wiring problem detailed above, but everything was cool on my A0 truck, so out came the manual. And yeah. So, some dimwit had mixed up the relay for the Exciter with the relay meant for the Starter. Both are 24V. Both will plug right on in. But the Starter relay is a 4-pin, and the Exciter relay (K11) needs to be a 5-pin. Swapped them back and...voila! All works as it should. I have to thank the horrible, horrible 'flow-chart' style -20 manual for pointing me there ('horrible' in that I hate the flow-chart-mechanix-4-dummiez approach which takes 120 pages to convey 12 pages worth of info.) Hope that helps others.

Wile, you saved me! I had did the exact same thing with the same relays. I took the alternator out and taken it into a shop only to have them look at me and say what's that! I told them I'll just take it back home and put it back in the truck so I can still drive it. I also told them, I'll get on steelsoldiers and do some reading. Well this site pays off big again. Thanks so much Wile and you others that contribute.

 

[fire16]

Do still have the spare alternator? I am interested if you want to sell.
thank you

 

[NV555]

On my 1083 my 100 amp duel failed. I replaced it a 200 amp duel off a HMMWV . working fine no issues . is the 400 amp duel the largest for the LMTV or do they have a 570 option like on the MRAP.

My 100 amp failed when the cab grounded the alternator. I added a rubber pad to the cab so I don't have to worry about contact in the future.

 

[NDT]

On my 1083 my 100 amp duel failed. I replaced it a 200 amp duel off a HMMWV . working fine no issues . is the 400 amp duel the largest for the LMTV or do they have a 570 option like on the MRAP.

My 100 amp failed when the cab grounded the alternator. I added a rubber pad to the cab so I don't have to worry about contact in the future.

Good to know. You are saying the little yellow terminal on the 200 amp HMMWV alt (intended to power the 4L80E brain) has enough azz to run all the 12 volt loads on a FMTV? Thats a lot of amps when you figure lights and heater fan.