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Tesla Model S/X motors have high power ratings, but cannot sustain high power because they overheat - they're not for heavy-duty use. Lots of heavy vehicles have been converted (although not in this forum), there are very heavy EVs in production (such as 25-ton buses), and big pickup trucks are coming. They key is to use a big and well-cooled motor and corresponding controller.
 

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Now that would be a build I'd like to see and follow. What would your approach be on taking this project on? Is it something currently in the works or a dreamers goal to get to? I can only imagine the cost endeavored to take on something like this! Good luck to you and hopefully some of us can help you along the way.
 

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Fiat 124 Spider (Kostov 11HV), BMW 330Ci (NetGain 11HV), Piper Aircraft Malibu (YASA)
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Discussion Starter · #6 ·
Now that would be a build I'd like to see and follow. What would your approach be on taking this project on? Is it something currently in the works or a dreamers goal to get to? I can only imagine the cost endeavored to take on something like this! Good luck to you and hopefully some of us can help you along the way.
Vehicle being acquired now. We have a version of powertrain that I would want to apply to this already. I am thinking a team of ~3 people working on it. Looking for folks to hire, potentially. I think it will cost us maybe $100k to do.
 

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I assume that's an M977 Heavy Expanded Mobility Tactical Truck (HEMTT). The Oshkosh ProPulse series hybrid system but with the diesel generator set and ultracapacitor bank replaced by an enormous battery would be a battery-electric version. Of course you probably can't buy a ProPulse HEMTT (apparently called the HEMTT A3) as surplus, but you can copy the design: it puts a motor and gearbox unit at each axle (retaining the stock TAK4 suspensions).

Just keep in mind that the specs for the hybrid suggest that total motor power is well over 300 kW (as you expect), which this vehicle would need, and that energy consumption will be kilowatt-hours (not just a few hundred watt-hours) per kilometre, so any significant range will require hundreds of kWh of battery. The truck can carry that, but you have to buy it! The hybrid isn't as heavy as the conventional version, but that battery will presumably be heavier than the diesel generator set.

Those specs include "Drive Motors: Moog – 460 VAC", which is interesting... I didn't know that there were Moog drive motors. The TruckTrend article says that these are induction motors. Moog's traction motors range from 47 kW to 90 kW, so the ProPulse system could be anywhere from 47 kW to 180 kW per axle, depending on which motor and whether there are one or two per axle.

The truck uses axles with planetary reduction gears at the hubs; of course additional reduction gearing is required, and the hybrid uses a two-speed transmission. At ten times the mass of a typical car and double that loaded (triple that towing the maximum trailer) 300 kilowatts is really not very much, so the motors will typically not be big enough for adequate low-speed acceleration without a lower gear.

I'm a little curious: why convert one of these? There are not a lot of practical uses for these trucks, and fewer for an electric version.
 

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I have been thinking of a project similar to this, and have a drivetrain design you might be interested in. Since my design has been just a thought experiment with no intention of ever being able to build it so ill share.

It is an engine directly linked to a locked differential gear. Each axle side connects to a planetary gearset or "power split device". The output is solidly connected to the wheel and the electric motor functions as a typical hybrid b drive motor but is in fact the traction motor. This allows independent and careful control of the exact wheel speed, an infinite gear choice and integrated yaw, traction, and limited slip control. The output would be the the planet carrier and the electric motor would be best used connected to the sun gear. This requires a hollow sun gear for the planet carrier outout to pass through. By locking all 3 parts together you can have a cruise mode where the combustion engine powers the wheels in a direct drive situation. This allows the electric motor to coast, contribute power or draw power from the combustion engine to charge batteries. If a transmission is incorporated the vehicle can operate on full electric or full combustion power. The one downside is that the electric motors will offer the best acceleration in full electric mode and the combustion engine will need a pinion brake setup or some sort of lock to isolate it. Permanent magnet motors could work well in combustion only mode as they will increase delivered torque as engine speed increases naturally and provide a natural limited slip failsafe mode
My thoughts were to use an undersized combustion engine that could instantly tap into the power of the electric motors and batteries. This means maximum fuel economy because of a high throttle engine with a massive amount of power on tap to help accelerate or maintain speed when not on flat ground. This would also allow the vehicle to operate a a mobile generator

My design incorporated the power split device at the end of swing axles and inside 6ft diameter "air suspension wheels". An additional portal axle gear reduction was planned for mine to compensate for the loss of ride height and extremely large wheels. It calls for a 500hp diesel with say 8 tesla motors on tap at will. This offers a very impressive amount of power

The continously variable gear ratios should offer about a 25% increase in acceleration of the combustion engine whatever it's outout

I'd like to watch the progress on your project, im jealous your able to pursue it
 

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Of course you probably can't buy a ProPulse HEMTT (apparently called the HEMTT A3) as surplus, but you can copy the design: it puts a motor and gearbox unit at each axle (retaining the stock TAK4 suspensions).
Sorry, that should have been "using" instead of "retaining" TAK4. As anyone looking at an actual stock HEMTT realizes, it uses beam axles; the TAK4 independent suspension is a regular Oshkosh product, but used for HEMTT only on the ProPulse.
 
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