No, Hollywood star Jason Momoa hasn’t joined the cast of the Peaky Blinders movie. This 1929 Rolls-Royce Phantom II is actually his car, and its conversion to electric power has been chronicled for his documentary series called ‘On The Roam’. While you should definitely watch the show, the team behind the build, Electrogenic, has shared some behind-the-scenes tidbits about its fully-reversible EV conversion of Momoa’s car.

The company says it always works to ensure that its electromods do not modify the car in a way that cannot be undone. Fortunately for it, there was a huge engine under the hood that provided a lot of space for batteries.

Indeed, the team carefully removed the 7.7-liter straight-six that originally powered the car and replaced it with a 93 kWh battery pack. To ensure it doesn’t look out of place in the engine compartment, it has been covered with a hand-formed and hand-riveted aluminum cowling.

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Meanwhile, power comes from an electric motor that makes 201 hp (150 kW/204 PS), about four times more than the engine did in 1929, when it was rated at between 40 and 50 hp (30-37 kW/40.5-50.6 PS). A reduction gear converts the 229 lb-ft (310 Nm) of torque the motor makes to 737 lb-ft (1,000 Nm) of torque at the prop shaft, which should be plenty to hustle even the largest and most muscular of actors around.

Converting a vehicle this old to electric power isn’t as simple as swapping the drivetrain, though. Electrogenic had to figure out how to power the car’s “through-flow” chassis lubrication system. Necessary to keep the phosphor bronze bushings and linkages in good working order (and normally run by the engine), the team had to hide a new pump in the vehicle to ensure that the Rolls-Royce’s trademark smooth ride wasn’t compromised.

The company also had to figure out how to improve the cable-operated brakes. It hid a hydraulic system between the pedal and the original cable actuators to improve performance, and to allow the system to work in tandem with the motor’s regenerative braking system.

Inside, Electrogenic repurposed some of the gauges to better serve the car’s new powertrain. For instance, the fuel gauge (formerly a vertical sight glass) now serves as an LED state of charge gauge. Meanwhile, the amp meter now serves as a power gauge, tracking the rate of the power draw under acceleration, and how much energy the regenerative brakes are harvesting.

According to Steve Drummond, Electrogenic’s director, the result is a surprisingly cohesive package, despite the massive changes under the surface.

“It’s a delight to drive, a Phantom that performs as Rolls-Royce’s engineers of a century ago would have wanted had they possessed the technology available to us today,” said Drummond. “It is silent, effortless, and graceful.”

You can see Momoa’s reaction to his new car on his TV series, On The Roam, which is now live on Discovery+ and HBO Max.