Jason Momoa’s 1929 Rolls-Royce Phantom II, converted to clean electric power by Electrogenic

Kidlington, Oxfordshire – 8 February 2024

The internationally renowned British EV technology company, Electrogenic, has revealed that the stunning 1929 Rolls-Royce Phantom II it recently converted to clean, all-electric power was completed for a very special customer: Jason Momoa – star of Game of Thrones, Aquaman and Dune.

The all-electric Phantom and Electrogenic’s talented team of engineers and fabricators play a starring role in Momoa’s documentary series, On The Roam, which is available to watch now on Discovery+ and HBO Max. The series follows Momoa as he travels around the world, meeting extraordinary individuals blazing their own creative paths – from craftsmen and motorcycle fabricators, to musicians and athletes.

On The Roam captures the painstaking process of converting the remarkable Rolls-Royce Phantom II, which features original coachwork by HJ Mulliner & Co, to electric drive. Working closely with Momoa, a car enthusiast who’s deeply passionate about the environment, Electrogenic has given the stately Phantom II the silent, effortless powertrain that Charles Rolls and Sir Henry Royce – both early pioneers of electric motors – would have perhaps chosen had the technology been available to them.

Jason Momoa, said: “In order to pull off this dream project, I had to find the right partner. I needed a team that would appreciate the stored history of this car while updating its technology. Electrogenic is all about honouring vintage cars. Making them electric without losing any of the vehicle’s character. They were the perfect fit.

Steve Drummond, Director, Electrogenic, added:We’re delighted to finally reveal the full details of this car to the world. It has been a labour of love for everyone at Electrogenic, and a lot of fun, working with Jason over the course of 18 months to bring his vision to life.

“Our team of engineers, programmers and fabricators have poured their hearts and souls into Jason’s beautiful Phantom II. This is undoubtedly the most complex classic car EV conversion ever undertaken, so the stunning results really are a testament to the world-leading talents of our team. We’re immensely proud of the finished car, and humbled that Jason entrusted us with this landmark project.

“Now, for our work and team to be showcased on screen by Jason alongside other passionate craftspeople, really is the icing on the cake. It’s the perfect way to celebrate this Phantom II, which is now future-proofed for another hundred years of stately motoring.”

Transformed Mechanicals; Ingenious Packaging
Electrogenic, also famed for its range of revolutionary, award winning, ‘drop-in’ EV conversion kits for popular models – offered in the UK, USA and beyond by its partner-installer network – has sympathetically modernised this jewel of British automotive history. The 1929 Phantom II now packs a whisper-quiet, effortlessly powerful electric powertrain, featuring Electrogenic’s proprietary EV technology. The Phantom’s sublime original aesthetics and timeless features are retained, and as with all of Electrogenic’s projects, the conversion is entirely reversible.

The car was originally powered by a gargantuan 7.7-litre pushrod straight-six engine, producing between 40 and 50bhp, bolted directly to a four-speed, non-synchromesh manual gearbox. In standard configuration, Rolls-Royce claimed a top speed of ‘well over 80mph’. Now, the petrol engine and gearbox have been carefully removed and replaced by 93kWh of batteries, which have been precision-integrated into the existing structure of the car.

The batteries feed an electric motor mounted between the chassis rails via a custom single-speed direct drive transmission, channelling 150kW and 310Nm of torque to a fixed reduction gear, which in turn delivers 1,000Nm to the prop shaft. The systems are all seamlessly linked and managed by a bespoke suite of software – all developed in-house by Electrogenic’s engineers.

As with every Electrogenic conversion, the battery configuration has been tailored specifically to the model in question; all housed within the car’s original architecture, no modifications are made to the structure itself. This is made possible thanks to Electrogenic’s world-leading battery system design capabilities.

In the case of the Phantom II, Electrogenic has made use of the considerable space vacated by the engine and gearbox, installing the batteries under the bonnet and between the chassis rails.

Showstopping Design Flair
The batteries themselves are housed beneath a gleaming, hand-formed, and hand-riveted aluminium cowling – a sculptural design element that delights every time Phantom’s centrally hinged bonnet is raised.

The battery installation and ornate cowling perfectly illustrate the Electrogenic team’s ability to deliver a fully sympathetic re-engineering that combines cutting-edge technology and innovation with show-stopping design flair.

Engineering challenges; creative solutions
Naturally, there were a number of challenges associated with sympathetically converting a near century-old, idiosyncratic luxury motor car to run on the latest EV technology. Electrogenic has used its deep reserves of engineering expertise and resourceful creativity to deftly solve them.

One key challenge was devising a way to preserve and update the Phantom’s centralised, entirely mechanical, ‘through-flow’ chassis lubrication system. This system was designed to send oil to the car’s many phosphor-bronze bushes for brake and suspension linkages, as well as other mechanical control systems – crucial to the Rolls-Royce trademark silken drive.  As foreseen, the complex system was disrupted by the removal of the straight-six engine, however, Electrogenic supplemented its design to ensure it continued to work as intended.

Another challenge the faced was re-designing the original cable-operated braking system to work seamlessly with the updated EV architecture. The original brake pedal and levers sat under the bulkhead in space now taken by the large battery pack and the brake servo was housed in the (now removed) gearbox.  With a solution that encapsulates Electrogenic’s core belief in creatively preserving the character of each car it works on, the team re-positioned the original brake levers and cables, even maintaining the original ratios of the mechanical balancing system, but in a new configuration.

The brakes are operated by a re-engineered pedal with braking power significantly amplified by a new hydraulic system installed between the pedal and the original cable actuators. As a final touch, the Electrogenic team calibrated the brakes to work in tandem with the motor’s energy regeneration function, further enhancing braking performance while also boosting efficiency and range.

The braking system shows Electrogenic at its best: elegantly engineering old and new technology to work in harmony – preserving original features and character wherever possible while delivering transformed functionality, useability and environmental compatibility.

Discreetly updated Interior
The programme of sympathetic updates continues inside, where Electrogenic has been careful to retain the wonderful original features of the beautiful leather and wood-lined cabin. The original controls have been repurposed, and the standard gauges have been creatively re-purposed. The fuel gauge, originally a vertical sight glass, is now an LED state-of-charge gauge. The amp meter has become a power gauge, showing the rate-of-power draw under acceleration, and power harvesting under regeneration. The oil temperature gauge now shows charger temperature, while the water temperature gauge shows the temperature of the electric motor.

The modernisations for Momoa’s car also extend to the audio setup: the cabin now houses a state-of-the-art, high-end multi-speaker HiFi system, with an integrated sub-woofer and full Bluetooth connectivity. All of this is discreetly hidden from view.

Driving Experience: A Phantom Transformed
Drummond added,The car’s diverse elements all add up to deliver a stunning, cohesive package. 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. It is silent, effortless, and graceful.

“While transformed in terms of performance and ease of use, as with all our conversions, the car’s tuning, and calibration – honed over countless test miles – have been finely honed to reflect the original character of the car. Rather than transforming it beyond all recognition, the Phantom drives like an enhanced version of its original self.”

For example, the electrified classic is now effortless to start, with smooth, quiet acceleration and no-need for double de-clutching – making it much more useable in traffic. The updated braking system effortlessly slows the two tonne Rolls-Royce, giving the driver much greater confidence whether in town or cruising on the open road.

The updated machine is also vastly more efficient than the original; despite its significant weight and a drag ratio of close to one, the state-of-the-art powertrain with regeneration capabilities offers a range of circa 150 miles in real-world driving. Electrogenic has also engineered in different driving modes, with normal ‘Drive’, range boosting ‘Eco’ and high-performance ‘Sport’ settings.  There is also a ‘regen doubler’ setting for the regenerative braking, which the driver can deploy on long, steep descents.

Drummond concludes: “We’re honoured to have been asked to build this special car for Jason Momoa, who really loves his cars and is deeply passionate about the environment. It’s been an immensely rewarding collaborative process with him, bringing our shared vision to life to the highest possible standards.

“It’s been an engineering challenge of course – from initially exploring the feasibility of the project and technical specifications, to then developing different rendered options for how we would integrate the EV componentry. This included options for how the batteries should be displayed under the bonnet. However, this level of choice is all part of the premium ultra-bespoke conversion service we offer our clients.

“While it sounds like we’ve carried out a great deal of modifications – and we have – I’m particularly proud of the fact that, as with all Electrogenic conversions, nothing has been drilled or cut on the car. We have simply unbolted some of the original parts, and bolted new parts in.  All of the original components can be reassembled and the car can be returned to its original state at any point, if required.

“This really has been a fascinating project to work on, and one that we’ve poured our hearts and souls into. We’re delighted with the results; it combines the most stunning 1920s coachbuilding with an updated driving experience that’s entirely befitting of a Rolls-Royce. Every single member of the Electrogenic team has contributed to this project and we are all proud to have added our mark to this remarkable motor car, readying it for a further hundred years of dignified, stately – and now clean – motoring.”

Background: Cutting Edge Technology, Developed in Britain
Electrogenic’s conversions – whether bespoke projects or its award-winning range of ‘drop-in’ kits – feature the firm’s sector-leading, proprietary EV technology, which has underpinned the company’s rapid rise and sustained growth in recent years.

All Electrogenic conversions are defined by their quality and depth of engineering, using technology developed in-house by a research and development team comprising leading automotive engineers, programmers, and electrical experts.

Each conversion reflects Electrogenic’s approach of developing and manufacturing its own technology, which includes in-house designed software, printed circuit boards (PCBs) and digital dashboards, as well as vehicle management technology that can integrate any of the latest motors, battery modules, to incorporate the best new tech into its conversion packages.

The conversions use highly innovative mechanical componentry, including a unique system for creating high-density battery packs, as well as exceptionally compact in-line and transverse reduction transmission systems, all manufactured in the UK. The cleverly packaged conversions always ensure that the original vehicles’ existing structure and architecture are preserved. This approach ensures that all Electrogenic conversions are entirely reversible.

Electrogenic’s world-leading bespoke conversions are completed at Electrogenic’s Oxford HQ and workshop, while the ‘drop-in’ kit range is offered internationally through a rapidly growing network of partner installers.

To learn more about Electrogenic, visit:

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