# Converting a Unimog to an EV



## Gazz58 (Oct 5, 2017)

The flat 6 in a unimog produces 142 Kw or 190HP and 610 NM torque. What sort of elctric motor will match that. Or maybe a combination of motors?

Gazz


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## jwiger (Oct 18, 2014)

Gazz58 said:


> The flat 6 in a unimog produces 142 Kw or 190HP and 610 NM torque. What sort of elctric motor will match that. Or maybe a combination of motors?
> 
> Gazz


What do you want to do, and how fast do you want to do it?

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## Gazz58 (Oct 5, 2017)

jwiger said:


> What do you want to do, and how fast do you want to do it?
> 
> Sent from my STV100-1 using Tapatalk


I just want to match the existing capability


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## jwiger (Oct 18, 2014)

That's very vague. Are you using it as a truck or a tractor? How far/long does it need to go? Unimogs are used for all kinds of tasks from log trucks, snow plows, trailer pulling or mobile powerstations by way of PTOs and hydraulic outputs. 

There are plenty of electric motors that can get the job done for you. But that is not where the power really comes from. Consider the motor an extension of a transmission. The actual power is produced by the battery pack. 

Let us know what you want/need to do. The first thing to figure out is the battery pack, then the motor(s). 

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## Gazz58 (Oct 5, 2017)

jwiger said:


> That's very vague. Are you using it as a truck or a tractor? How far/long does it need to go? Unimogs are used for all kinds of tasks from log trucks, snow plows, trailer pulling or mobile powerstations by way of PTOs and hydraulic outputs.
> 
> There are plenty of electric motors that can get the job done for you. But that is not where the power really comes from. Consider the motor an extension of a transmission. The actual power is produced by the battery pack.
> 
> ...


I am thinking of building an RV type arrangement using a unimog flatbed truck, removing the motor, fuel system and tanks and using the existing drive train but running it all with electric motor (s). I thinking a li ion battery system augmented by solar pannels across most of the roof to top up the battery bank.
Gary


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## jwiger (Oct 18, 2014)

Now, were getting somewhere. What do you expect the final weight to be and what are you looking for with range?

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## Gazz58 (Oct 5, 2017)

jwiger said:


> Now, were getting somewhere. What do you expect the final weight to be and what are you looking for with range?
> 
> Sent from my STV100-1 using Tapatalk


realistically about nine ton overall weight. The truck is about eight ton with a diesel configuration. The range about 1500Ks with a mounted diesel generator as a back up.


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## jwiger (Oct 18, 2014)

I don't recommend this conversion for a first timer. 1,500km on battery alone is currently impossible. Traveling at highway speeds with this weight will take over 100hp (75KW) on flat ground. 

General rule of thumb for cars when planning batteries for range is 100Wh per 1000lbs per mile. Nine tons is 18,000lbs, so at least 1,800Wh per mile. A Km is 0.62 miles, so 1116Wh/Km. Your range of 1500km would require a minimum of 1674KWh of energy. A used Nissan Leaf battery pack is approximately 20KWh and sells for about $5,000 US. You would need 84 of those battery packs for a cost of $418,500 US. 

If you go minimum on your battery pack, and depend on the generator you will add weight and complexity. A standalone Generac 80KW genset weighs 2,425lbs (1,100kg) without the fuel tank or enclosure. The primary traction motor to sustain highway speeds would exceed 200Kg and a single Leaf battery pack would weigh similar to the motor. 

You can't do much to change the weight of this vehicle, but if you adjust your range goal down a lot, we might be able to help you. 

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## Gazz58 (Oct 5, 2017)

jwiger said:


> I don't recommend this conversion for a first timer. 1,500km on battery alone is currently impossible. Traveling at highway speeds with this weight will take over 100hp (75KW) on flat ground.
> 
> General rule of thumb for cars when planning batteries for range is 100Wh per 1000lbs per mile. Nine tons is 18,000lbs, so at least 1,800Wh per mile. A Km is 0.62 miles, so 1116Wh/Km. Your range of 1500km would require a minimum of 1674KWh of energy. A used Nissan Leaf battery pack is approximately 20KWh and sells for about $5,000 US. You would need 84 of those battery packs for a cost of $418,500 US.
> 
> ...


I think I will look for a light truck to reduce the amount of power required.


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## arcturus (Sep 23, 2016)

Hello guys, how are you all? Well, this thread has a couple of years old and i would like to bring this question back to life. I have in mind a project to convert an unimog to 100% electric, no so powerfull, it is used to transport people in a dirt road, 15 mph topsped, no hills.
So, i would like to read your expert opinions and suggestions fot the motor and controller for a project like this.

Thanks.


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## jwiger (Oct 18, 2014)

How far will you need to travel before charge ups?

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## arcturus (Sep 23, 2016)

Hi jwiger, thanks for your answer. I estimate that the maximum distance for this unimog will be 37 miles, but i think the mog have to got enought juice for 50 miles.


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## Joe Fox (Nov 16, 2020)

I'm not looking for such a large Unimog settup. I have a 404 Unimog that weighs 2900kg. I want it to have a range of 50-75 miles for local cruising and the occasional parade that has a 5 mile route length. The bed of a Unimog is 7' wide x 9' long and I intend on making a 7'x9' solar array on the roof which should produce 900w. I will also have a small generator box where the factory fuel tanks are located for making power on cloudy days or at night. The straight 6 engine is a Mercedes M180 which has a peak output of 110hp. What motor, battery type and qty, controller etc would you guys recommend. My shop has CNC plasma tables, CNC routers and CNC press brakes to make any kind of motor to tranny adapters, battery trays or brackets needed. Thanks for any help you guys can provide.


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## remy_martian (Feb 4, 2019)

Need to know what speed you plan to run, what grade you plan to run at that speed, and how much payload you plan to carry/tow.


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## Joe Fox (Nov 16, 2020)

Flat grade. Unimog portal axels top out at around 45mph. It can carry 2 tons but I don't use it for hauling big loads. Maybe 1/2 -3/4 ton of cargo at most.


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## Vtu99 (Nov 19, 2021)

Joe Fox said:


> Flat grade. Unimog portal axels top out at around 45mph. It can carry 2 tons but I don't use it for hauling big loads. Maybe 1/2 -3/4 ton of cargo at most.


Actually this Unimog (S404) tops out at 55-60 in some cases. You are thinking of the heavier u900/406 models that at max RPM of 2800 - max out around 45 mph 

all that said there is a lot of rolling resistance in the running gear (reduction hubs, portal axles , differentials, gearbox etc. eliminate the poorly designed 404 gearbox will go a long ways to solving many issues (the gearbox is a 404’s Achilles heel)


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## Mountain42 (5 mo ago)

Joe Fox said:


> Flat grade. Unimog portal axels top out at around 45mph. It can carry 2 tons but I don't use it for hauling big loads. Maybe 1/2 -3/4 ton of cargo at most.


Joe - Did you end up converting your 404 to electric?


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## jamesdh (2 mo ago)

If one were to eliminate the engine and entire drivetrain and somehow implement a direct-drive system per wheel, how feasible would this now be w/ a Unimog 404 today? How powerful would each motor ideally be?


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## remy_martian (Feb 4, 2019)

It's no longer a Unimog if you do anything per wheel.


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## brian_ (Feb 7, 2017)

jamesdh said:


> If one were to eliminate the engine and entire drivetrain and somehow implement a direct-drive system per wheel, how feasible would this now be w/ a Unimog 404 today? How powerful would each motor ideally be?


Direct drive to the large Unimog tires for use at low speed? The required motors would be ridiculously large. If you used appropriate reduction gearing it would work, but would you basically throw out everything that makes it a Unimog, or would you build custom axle assemblies with the motors mounted to custom axle beams, retaining the portal-geared hubs? Those custom axles would be a major project.

Power per wheel is basically just one-quarter of the total power needed for acceptable performance. A 404 is very low-powered by current standards for its weight - the most powerful of them had the same 80 kW as a Nissan Leaf.


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## ADK46 (2 mo ago)

I don't know a lot about 404's, but I do own a 406 - more or less the bigger, diesel successor to the 404. Mine is a 20 speed. A cordless drill could power it in the lowest "super crawler" gear, at a speed best measured in inches/hour. The ~80 HP engine is at redline at 45 with the standard axles (earplugs recommended); there are such things as "fast" axles with taller gearing. You see, the portal axles incorporate gear reduction. That's the only good news re: electrification.

Owners use the phrase "Mog Stink" for the smell the old Diesel engines produce. 

There are torque tubes fore and aft, to differentials and solid axles. They articulate at the gearbox, so picture a rigid "T" held at the base of the "T" They and the frame of the vehicle are meant to rotate; the motor/gearbox is mounted at three points to allow the frame to flex in torsion. You gotta see all this to believe it. 

I normally carry a 3000 lb counterweight at the rear. So maybe that's good news, too - swap it for 3000 lbs of lead acid batteries. Bolt a modest electric motor to the gearbox, and enjoy a slow, silent and stink-free 'Mog. 

I'm half serious!


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