Dual alternator

[Givinup]

Has anyone setup dual alternators on an lmtv or fmtv? I'm thinking of putting a 12v battery bank in the cab, and am thinking of a dedicated alternator for it.

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[DiverDarrell]

Going to be tricky as there isn’t much space, less after an ac install

 

[Givinup]

Going to be tricky as there isn’t much space, less after an ac install

I think for ac I am planning to do a box mounted system, similar to fire trucks. I'll avoid an engine mounted compressor if at all possible. This is an additional reason for another battery bank and alternator.

The 200 amp alternator seems really expensive, although I guess that could serve as the 2nd one.

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[snowtrac nome]

Why not use a dual voltage alternator? I think most came with the 200 amp dual voltage model. I know that is what my a-0 had I also picked up a spare when I got mine.

 

[coachgeo]

Why not use a dual voltage alternator? I think most came with the 200 amp dual voltage model. I know that is what my a-0 had I also picked up a spare when I got mine.

If not mistaken most came with a dual voltage 100amp alternator. If you got the 200amp on yours then you got a huge bonus.

 

[snowtrac nome]

no the huge bonus was the new spare one that came with the truck. But yes mine had the 200 amp model like the a-1's we had in Iraq which were equipped with lsa cabs and a-c.

 

[scottmandu]

The LTAS trucks got a 240 amp alternator if I am remembering correctly. The 200amp was a retrofit for the earlier trucks.

 

[Givinup]

Unfortunately I just have the 100 amp alternator. That being said, I havent looked much at the dual voltage capabilities. Maybe 100 amps is big enough with a large enough battery bank.

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[coachgeo]

Unfortunately I just have the 100 amp alternator. That being said, I havent looked much at the dual voltage capabilities. Maybe 100 amps is big enough with a large enough battery bank.

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Rummer is these alternators are way underrated. The top figure (100, 200 etc.) is the rate under adverse conditions spec. if I recall right.

 

[snowtrac nome]

A hundred amp alternator can keep up with an electric snowplow motor, lights and heater, it can also keep an 8k electric winch running longer the motor can run with out overheating. Unless you are trying to run stadium lighting you should be in plenty good shape. If you are trying to run a coach battery you might want to add an isolation relay or a diode isolator if you want something passive. I remember some guy having me retrofit his ford van to a large frame ford alternator because he installed a 100 watt amp. I played he!! trying to explain there is no way that thing was going to draw a hundred amps through the little 16 gauge wires powering it. I know I could have showed him an equation with volts divided by watts but this was way beyond him.

 

[Givinup]

A hundred amp alternator can keep up with an electric snowplow motor, lights and heater, it can also keep an 8k electric winch running longer the motor can run with out overheating. Unless you are trying to run stadium lighting you should be in plenty good shape. If you are trying to run a coach battery you might want to add an isolation relay or a diode isolator if you want something passive. I remember some guy having me retrofit his ford van to a large frame ford alternator because he installed a 100 watt amp. I played he!! trying to explain there is no way that thing was going to draw a hundred amps through the little 16 gauge wires powering it. I know I could have showed him an equation with volts divided by watts but this was way beyond him.

Great to hear. I'll push forward with my plan and test it out.

Do you know if the alternator can charge 2 totally separate battery banks? The current 24/12v are wire in series & parallel, but from the same ground. This other bank would have separate ground and be placed within the cab or at least in another location.

I won't be charging a coach battery bank. My plan is to have a separate battery bank of 12v items that will be used in the cab. Stereo, led light bar, and ac condenser. This way my original battery and vehicle systems stay separate from any items that aren't essential for the operation of the vehicle.

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[scottmandu]

The LMTV system is grounded to the frame of the vehicle, so anything else grounded to the frame will have the same ground. If you don't ground it to the frame you will have zero potential.

 

[coachgeo]

..... This other bank would have separate ground and be placed within the cab or at least in another location. ...

Would not put in cab. That is a added weight to to raise up when tilting cab.. and a lot of damage if one was loose and you did not realize it. As it fell it would destroy your windshield, your dash possibly etc. Then again there is out gassing when charging..... would potentially be very unhealthy for you as you drive with alternator charging them.

 

[Givinup]

Would not put in cab. That is a added weight to to raise up when tilting cab.. and a lot of damage if one was loose and you did not realize it. As it fell it would destroy your windshield, your dash possibly etc. Then again there is out gassing when charging..... would potentially be very unhealthy for you as you drive with alternator charging them.

Both great points. I have a 12v lithium unit I need to do something with. That being said it makes more sense to add a second bank either where the gas tank is now, between the rails, or where the air dryer is.

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[Duckworthe]

Would not put in cab. That is a added weight to to raise up when tilting cab..

Good point coachgeo. I have my aluminum roof rack (80lbs), Tools in box behind drivers seat (100lbs) and some other items like interior panels and that sort of add-on's, I have pelican cases on rack with some camping gear and some spare parts in them also. Probably about 150lbs there. And it gets to the point that my ram is struggling already. But who knows, mine might be about wore out. It will lift it but its not as smooth as when the cab is empty. It tends to want to bounce a little on the way up fully loaded. Could use a bigger ram for sure! using the manual pump, it goes right up smooth.

 

[snowtrac nome]

You could charge off the 12 volt stud or one of the 12 volt battery terminal's. You likely would want some kind of isolation, like a diode, or key activated relay to keep your aux load from drawing down your starting battery's when the engine isn't running.

 

[xomegaiv]

Has anyone setup dual alternators on an lmtv or fmtv? I'm thinking of putting a 12v battery bank in the cab, and am thinking of a dedicated alternator for it.

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Give Ron from Double-alt.com a call. Much cheaper replacement dual charging alternator than the originals. The alternator is made from common alternator parts that can be change/replace/fix by any alternator shop. We have over 2500 miles on ours and still running strong. The current output on the alternator is 120 amp at 24 and 145 amps at 12.


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[DOUBLE ALT]

Hello
Soon on SS I will have my double alternator as a vendor. Just waiting for Paypal and credit card merchant approval.
I can answer basic questions without trying to sell you.
Niehoff and others try to sell you a dual voltage alternator output. While this is true you get 2 voltages, you are limited to total watts the alternator can produce. For instance the popular 100 amp at 28 and 14 volts only has 2800 watts. The alternator produces 2800 watts at 28 volts max. It uses CRT technology converting 28 volts down to 14 volts as you need it.
It uses diodes and a regulator to make it happen. If you load it with 14 volt stereo, AC, Big amp lighting, all at 14 volts, it then has little 28 volt power for the engine and transmission, gauges etc.
More to come
Double Alt

 

[DOUBLE ALT]

A true double alternator can fix most of the Military Vehicles electrical issues. Soon it will be a vendor on SS.
Ron
Double Alt