The Plan

The Charging Bullet project has been a long time in gestation. It started a couple of years ago as an idea to build a super-economic diesel motorcycle and morphed through several incarnations before the idea of an electric motorcycle came together in the summer of 2017. Research into components revealed that prices have dropped far enough to make a battery vehicle project affordable and the technology has come far enough (as demonstrated by the likes of Tesla) to make the finished product a really useable machine.

However, not only has battery technology moved on leaps and bounds but so has the infrastructure. For the first time ever, the combined progress of the public charging network and affordable battery technology is making electric touring a reality. Even with the small range of this commuter bike a mammoth journey is achievable in the UK. The longest possible route is finally open to a battery vehicle – Land’s End to John O’Groats.

While I was looking for a mechanical project, old friend and excellent filmmaker Finn was looking for a documentary project. A chance comment in an email lead to a couple of meetings to arrange details and the Charging Bullet was born: an attempt to convert a classic bike to electric and ride it the length of Britain, all under the watchful lens of Finn’s camera.


I am Fred Spaven, a mechanical engineer with a passion for all things automotive, especially anything unusual. Following a career in superconductivity research, I decided to follow my real interests and set up Spaven Engineering; specialising in the restoration and modification of classic cars and motorcycles. The recent explosion of battery power is fascinating and I am starting my move into the world of electric vehicles with this Charging Bullet.

I am also no stranger to adventure having previously taken a Skoda to Mongolia, a BSA Bantam to south Italy, a train to Singapore and circumnavigated Yorkshire in a Reliant Robin. Now I am really looking forward to the new challenges of an electric adventure.


Finn Varney is a passionate, creative image-maker. He has shot short films, pop promos and commercials with visionary directors, making documentary films for commission and catharsis. He started filmmaking with production company Aberration in 2013, shooting a variety of documentary, web commercials and branded content. Working in smaller teams and as a solo operator, he specialises in working quickly and flexibly, capturing creative images in story-centric mindset and following most projects through edit and grade to delivery.

The Bullet

The Battery bike is constructed using the donor frame of an existing motorcycle, retro-fitted with a whole new electric drivetrain. After extensive searching for the right donor, the answer turned out to be right in front of my nose – an old Royal Enfield Bullet that, due to a hard life spent on the roads of India, was a near terminal case. I was looking for a frame that was simple, sturdy and relatively open and uncluttered to give space for battery boxes. Ideally new parts should be readily available and the frame and cycle parts should be in good condition. The part-restored Enfield fits the bill perfectly!

As for the electrical components, the starting point was the batteries. Traditionally the only affordably option has been Lead-Acid batteries which are heavy, bulky and prone to spilling. Fine for a milk float but not really motorcycle material. However, the last ten years have seen an explosion in battery technology with the likes of BMW and Tesla showing what is achievable with Lithium ion batteries. The bulk market, however, is the Nissan Leaf and there are now enough second hand batteries available that their cost is, incredibly, lower than Lead Acid batteries. It is this development that has made this project possible.

Drive comes from a Saietta brushed DC motor, providing 8.5kW at 48V, driven by a Kelly controller with the whole system kept in check by an Orion Battery Management System (BMS). This is all held in a steel subframe, designed and built by me at Spaven Engineering, that bolts into the Enfield frame in place of the original engine and gearbox. This produces a neat, well balanced bike that weighs the same as the original, with around the same power; and it is just as sweet to ride – although without the classic ‘thumper’ soundtrack.

The Route

The route took us from Land's End, up through the industrial Midlands where the Bullet was born back in 1961 and home to all manner of exciting new automotive developments. With Finn's camera running, we chatted to Ariel about their new, all electric 1,200hp 'Hipercar', rode bigas buses in Bristol and witnessed Nottingham University's electric race bike thrashing the petrol machines at Donnington Park. At Durham University we saw a Solar Challenge car capable of travelling across Australia without charging and a battery capable of recharging in seconds at Glasgow Uni.

All the way the bike performed well, with only the rider letting the side down. We had our first taste of peril in the Peak District when an icy bend caught me unawares and produced a few bends and scuffs on the otherwise resilient Bullet, which rode on regardless. A long night ride into Edinburgh got me lost in the suburbs, eventually draining the battery and leading to a short ride in the van of shame. The Highlands proved to be the trip's real nemesis, however, with several days of snowfall causing increasingly circuitous detours out towards the lower and warmer coast and interrupting our steady Northward progress. Finally, after 1,450 miles we reached John o'Groats and celebrated with a snifter of whisky at the end of the harbour wall, gazing out at the Orkney Islands offshore. A successful journey for a bike originally designed for a 35 mile commute!

Kits and Conversions

With a successful 1,400 mile trip complete, and the original Charging Bullet now in regular use, Spaven Engineering is offering electric conversions for your Enfield. We can supply anything from the parts needed to convert your bike yourself up to a complete conversion and customisation service. With the same weight and balance as the original 350 bullet but virtually silent running, the electric version is a joy to ride. It's 50 mile range and 50mph cruise speed are perfect for exploring B-roads or city centres and the twist-and-go control makes traffic a doddle. Conversions start at £5,000.

To discuss electric conversions call Fred at Spaven Engineering on 01885 482218 or email Fred@Spaven-Engineering.co.uk

The Film

The film is now in post-production and Finn is spending the winter months hunched over a computer getting it ready for the spring release. Dates are yet to be confirmed, so keep an eye on this site for updates.