Building the Ultimate Range-Extended EV Truck - My Dream Project inspired by Tesla, Lucid, and the Ramcharger

Over the last several weeks, I’ve had an ongoing conversation with ChatGPT to map out the specs for an EV truck project I’m seriously considering. The insights I’ve gained are mind-blowing, and if you’re on the fence about subscribing to AI tools, I highly recommend it.

The Vision

Inspired by the upcoming Ramcharger and frustrated by the lackluster performance of trucks at max tow, I want to design a range-extended EV truck that excels under load. My goal: a truck designed to perform flawlessly at max towing capacity. When unladen, it should offer insane performance—because why not?

I’m also obsessed with the builds from the Roadster Shop on YouTube. My plan is to collaborate with them to design a custom chassis for this setup.

Powertrain: Dual Tesla Plaid Drive Units

  • Twin Tesla Plaid Drive Units front and rear.
  • Each unit delivers massive power and torque:
    • Total output: ~1600hp and 2000 lb-ft torque
  • Available for $6,000-$8,000 each on the used market

Why Not Lucid Drive Units?

I’d prefer Lucid’s twin drive units for their efficiency and advanced design, but sourcing them is currently impractical (unless I buy a Lucid Sapphire just to strip it down—tempting, but ridiculous).

Battery Pack: Lucid Modules for 816V Architecture

To support the 800V architecture, I’m opting for Lucid battery modules:

  • Configuration:
    • 2 strings of 24 modules in series (total of 48 modules).
    • each module: 4.8 kWh, 34V.
    • Total capacity: 230 kWh at 816V.
    • Cost: modules are around $450 each, totaling about $21,600.

This setup should provide robust power delivery and high voltage efficiency.

Range Extender Generator: The Game-Changer

This is what truly sets the project apart. Inspired by the Ramcharger’s 130 kW onboard generator, I want to develop a compact, high-efficiency generator capable of producing:

  • Output: At least 100 kW continuous at 816V.
  • Fuel consumption: ~6 gallons per hour.
  • Fuel tank: 20 gallons (for about 3.3 hours of runtime).

Potential Engine Ideas

I’m considering high-torque motorcycle engines or expanding on the LiquidPiston rotary generator concept. Another exciting option is the MOTUS Baby Block V4 engine:

  • MOTUS Baby Block V4 Specs:
    • 1.6L, 180 hp, 123 lb-ft torque, and weighs only 150lbs.
    • Runs at low RPM, perfect for steady-state generator operation.

My main source of data here is between the Ramcharger range extender, and the Rawsuns range extender. Rawsuns seems to provide the only onboard range extender for 800V. But, it's only .8L producing 20kWh using the same ~6 gal/hr. We need a lot more development on range extenders in this scope.

Suspension: Independent, Adaptive, Heavy-Duty

To maintain high tow capacity and exceptional handling, the suspension system will feature:

  • 4-wheel independent suspension.
  • CNC'd Billet Aluminum control arms and components
  • custom ev motor subframes for a heavier duty structure
  • Triple-control system:
    • Air springs: for load support.
    • Sitting on top of hydraulic cylinders that can adjust for ride height.
    • Separate electronically controlled dampeners: independent control of rebound and compression.

Imagine a truck that doesn’t squat under load and handles like a performance vehicle when empty.

Efficiency and Performance Estimates

Here are the detailed specs and assumptions I worked out with ChatGPT (towing numbers based on a combination from what we've seen from many ev towing videos, and reports from the new Tesla Semi. Pepsi reported 1.7kw per mile at greater than 50mph and 80,000lbs):

  • Cruising speed: all estimates based on interstate cruising at 70-80 mph.
  • Power Consumption:
    • Unladen: ~40kwh (combined) for both Plaid drive units (using public data of 18-19kwh at 100kph/62mph for the Tesla model S Plaid).
    • Towing at least 10,000 lbs: ~120 kWh at 80 mph (assuming ~1.5 kwh per mile *Tesla Semi of closer to 2 kWh per mile at greater than 50mph).
  • Battery Pack: 230 kw (816V)
  • Range with Generator:
    • With a 20-gallon tank and 100 kWh generator: ~3.3 hours of runtime.
    • Total Range estimate while towing: ~420 miles at 80 mph (mix of battery and generator use).
    • Generator activates at 50% state of charge (115 kWh remaining)
      • Net drain: 20 kw per hour
    • Generator set to go off at 80% SOC, but while towing expect to run until fuel tank is empty.
      • When unladen, there is a net increase of ~60 kWh while cruising

Control Systems: AEM for Power Management

  • AEM is leading the way for control units and management systems in the DIY EV Market
  • Although they seem to be focused on 400V setups right now, the market is moving extremely fast, and 800V support seems inevitable.

The Cost Breakdown (So Far)

  • Tesla Plaid Drive Units: $6,000-$8,000 each (x2)
  • Lucid Battery Modules: $21,600 (48 units)
  • Custom chassis and bodywork: TBD (Roadster Shop quality) - I expect this to be six figures easy. well over $100,000
  • Range Extender: Custom development (engine + generator). I will even go to a local tech college to learn specifics here. SolidWorks will be imperative in order to flesh out ideas. I expect a few iterations required to be effective.

The range extender is the biggest unknown and potential bottleneck, but it’s the heart of making this project a reality.

The Body: Still Dreaming

I’m torn between several ideas. A combination of functionality/utility and luxury:

I've owned quite a few trucks with layouts that I love

  • 1988 Bronco - I like the removable roof with the cargo of a truck bed but retaining the interior comfort. But access to the back seat was a nightmare.
  • 2007 FJ Cruiser - suicide doors for back seat access was great. no leg room, but functionally good. This could be improved for my custom truck
  • 2015 F150 Supercab - the rear suicide doors are perfect, 180 degree opening. Access to the back is better than anything, even better than crew cab. With both doors open, putting dogs back there or cargo is excellent. If I kept this but had a back seat styled for SUV, I expect it to be even better.

I'm leaning toward using the wheelbase of a standard crew cab, 5.5-foot bed full-size truck. Which is the same wheelbase as my extended cab 6.5 foot bed.

This project combines cutting-edge EV tech with the practicality of heavy-duty towing and the flexibility of a range-extender. I think about it every day and I'd love to hear your thoughts. Input from more experienced and knowledgeable experts would be great.