Does anyone have any info on doing dual alternators on a 3500 dualie ? Interested in doing this mod for the drain on my optimal red tops from the use at the fd .......also on a side note recently did a bunch of body work on the beast and thought I would do a write up with pics for everyone ...but not sure how to post it any one able to help with this

May I ask what kind of load are you putting on the electrical system that 120 Amp alternator can hold? When I worked Salmon River Rural Fire Dept I would have all the light going including my overhead and just set the high idle and it could sit there and purr for hours without a problem...

It tops out easy. If I turn my brights on, windshield wipers on, HVAC on high, I am already over 60 amps. So then put an auxiliary load on it and you could top it out easy.

I would imagine you would need to fabricate another bracket, get another belt tensioner, and a longer belt. Since these trucks use the computer for voltage regulation you could either run an external regulator or junction the wire harness for both alternators.

I don't believe it's that simple. Having 2 alturnators charging the same battery bank... there will be interaction as one voltage regulator "sees" the voltage output of the other. I think finding a alturnator with enough output is preferable... otherwise one could isolate loads & have 2 battery systems with isolators.

I tend to agree with Russ on this...

The only way I could see running duals still would be make a fully stand-alone system.

[*]Separate batteries

[*]Seperate voltage regulator

Because Russ has a valid point you won't be able to tie a second alternator to the existing PCM without causing problems.

But still in all even with all the fire truck I worked on I've never seen a dual alternator setup for even some of the big rigs we had... All of them still managed just fine with 100-120 Amp alternators...

The only thing we did to keep the batteries up was high idle the engine at 1,000-1,200 and never had a problem...

I wouldn't deal with dual alternators. For the money I think you could get an upgraded alternator and better batteries (for high load). I know the 6.7 5500's come with a single 220 as an option (Mopar part # 4801313AC). From what I gather it puts out 193A at engine idle, and if you bump you fast idle up it gets to its rated output pretty quick. Even if that alt won't fit you can have yours rewound by most small electrical shops, and you could probably over-drive it for more idle output. (I did this on a 93 Toyota for winching and the difference was HUGE).

All of our Ford ambulances have come from the factory with dual 100 amp alternators but the second one has a second serpantine belt for just the second alternator. We have one Dodge unit and I'm not sure what it has on it.

Ford has an option on all their truck, not sure if it went past the 6.0 or not, for dual alternators. I don't see the point on 2 100's vs 1 220?

Ford has an option on all their truck, not sure if it went past the 6.0 or not, for dual alternators. I don't see the point on 2 100's vs 1 220?

Since it is on the ambulances I am going to guess they put two on just in case one goes out they will have another. Won't be good if their one 220A alternator goes out on the way to a life or death scene.

https://www.dcpowerinc.com/ Good company & good guys to deal with..

Since it is on the ambulances I am going to guess they put two on just in case one goes out they will have another. Won't be good if their one 220A alternator goes out on the way to a life or death scene.

No, that would be bad. But it was an option on all their trucks, not just the ones ready for ambulance upfit.

Duramax's have 2 as an option also. I do the "build and price" thing on the big 3's website and remember seeing it.

There are other products that would be better than dual alts, there are Generators that look like alternators but can handle much higher loads. We run them on a lot of Mine equipment that have like 4 million candle power worth of lights "Just an exageration" but probably not far off for some of them and that sit and idle with them on for extended periods of time.

I didn't realize GM jumped on that band-wagon too, but yeah a single 160 or dual 125's. Ford offers 157, 200, or combined for 357 total. And Dodge is still with a single 160 or 180, or 220 on 4500-5500's.

very good info here ....thanks to all that helped out ...as for the load on the truck i havent measured it specifically yet but most of the stuff is led warning lights .....a laptop computer for on scene info a 1200 watt stereo amp ..cell phone charger two way mobile radio pushing roughly 100 watts and a portable radio charger ....i believe the biggest problem is no high idle yet ....kinda haveing issues with my local dealer saying they r not sure if they can do the upgrade or not and if they can they r telling me it will take about three or four hours and around 250 bucks......admittedly I am not a service tech for a diesel but I dont believe that (A) it takes that long to connect a obdii tool erase one or two programms and install another one and (b) i cant really believe that it needs to cost that much to let a computer do most of the work. i have also noticed that the red top optima batteries seem to take a bit more to recharge....also my local dealer cant tell me if its a high 6 cylinder idle or a 3 cylinder or both ......i get the impression they dont want to work on a diesel there

I don't recall the VP trucks having the option for a manually controlled 6cyl fast idle, but I think Mike has a way to do it, as well as another member sells a kit. Do you run that stuff with the truck off much? Unless the truck is off or you're drawing more than the alternator makes your batteries aren't part of the equation. If you're running the stuff with the truck off the red tops are a poor choice for that kind of service.

The ambulances typically have a significant higher and constant draw than typical tucks. In addition to the emergency lighting, there battery chargers for portable equipment, interior lighting, and power inverter. And if one alternator goes out the second will at least last long enough to get us to where we're going and dead in the water. Most typical trucks even with off-road lights and a winch don't have as much of a load.

I don't recall the VP trucks having the option for a manually controlled 6cyl fast idle, but I think Mike has a way to do it, as well as another member sells a kit.

Yeah I do have a way... http://mopar.mopar1973man.com/cummins/2ndgen24v/high-idle/high-idle.htm Then talk to Prowelder if you want to purchase one... http://forum.mopar1973man.com/group.php?groupid=6