Words and Photography: Peter Henshaw

Fred Spaven is not your average classic bike restorer. True, he does commute to work on a BSA Bantam, and his shared workshop contains various British and early Japanese bikes as well as Frazer Nash parts and (when I visited) an ex-Jochen Rindt F1 project. But the Cambridge engineering graduate is young and wants to do something about climate change.

Based on a 1961 Royal Enfield Bullet chassis, the Charging Bullet looks vintage on the go. [Peter Henshaw]
“Being ecological was the reason behind building the electric Bullet,” he told me. “I wanted an electric bike I could do my daily commute on, which is 18 miles each way. I originally bought the Bullet to ride around the world, and I did use it for a bit, but it wasn’t very good, and when I took it apart, everything was shot. It had been exported new to India in 1961 and came back to the UK in 2009. In between times it had suffered decades of bodging – the crankcases were unusable, the gearbox, everything.”

No classics were harmed in the making of the ‘Charging Bullet’

That’s when the inspiration for an electric conversion took hold. Fred found secondhand Nissan Leaf batteries were the cheapest way to do it – over 350,000 Leafs have been built so far, so the batteries are cheapish and available. Better still, they come as self-contained boxes about the size of a laptop, so they can be stacked. It took a lot of research to find a suitable controller and battery management system, and he settled on a Saietta brushed DC motor. It was also important to him that the conversion was reversible, so he designed a subframe which would fit the existing engine mounts.

That’s right, you can relax, because no classics were harmed in the making of the ‘Charging Bullet’ as Fred calls it.  Re-converting to the original four-stroke single would be relatively straightforward. Two big alloy plates were cut to accommodate the twelve Leaf lithium-ion batteries, stacked in the big steel box which sits in the engine bay. Together, they add up to 6Kwh, and to put that in perspective, a typical electric moped has around 2Kwh, while a Zero offers 14.4Kwh.

The boxes holding the goods: batteries below, controllers above, motor behind. [Peter Henshaw]
A smaller box contains the all-important controller and battery management system, which do the clever stuff of power/torque delivery, and ensuring the batteries aren’t drained or charged too fast. The motor displaces the gearbox spot, and has direct drive to the rear wheel – being electric, there’s no need for a clutch or gearbox.  And despite the electronics, this is a simpler machine than a standard Bullet, with far fewer moving parts. “I wanted to make it as simple and efficient as possible, and since gearboxes have mechanical losses, direct drive by chain is the most efficient way of doing it. And I had to make the most of everything, to maximise range.”

Quiet country lanes remain so with an e-Bike. [Peter Henshaw]
By the summer of 2018 the Charging Bullet had covered a few hundred test miles around Herefordshire, part of the borderland between England and Wales. In November he rode Britain’s ‘end to end’, 1400 miles from Lands End to John o’ Groats, partly to prove the concept, partly so that filmmaker Finn Varney could document the trip. In short, it all appeared to work, but is the electric Enfield a practical proposition or just an interesting one-off?

E-asy Rider

Climbing aboard the Charging Bullet feels very familiar, with the same classic upright riding position as a standard Bullet, similar weight to the petrol-powered original, and even the view from the seat has barely changed, complete with headlight nacelle and single speedo. Only a couple of LED warning lights, plus a charge-meter in place of the ammeter, suggest that something is different.

Somewhere in your future is a bank of electric charging stations. Embrace it? [Peter Henshaw]
This is confirmed on startup, because there’s no kickstart. Instead, you turn the key on the left-hand side, there’s a loud click, a green LED lights up, and you’re good to go. Twist the grip and the e-Bullet takes off silently but slowly.  At 20mph it reaches its stride, and  acceleration improves as the speed builds – overall I’d say it was quicker than a 350cc Bullet, though when crossing a couple of busier roads I would have liked smarter acceleration from zero. Of course, being electric, it’s all completely smooth and seamless, not to mention silent. There’s a very faint whine from the motor and a gentle rustling from the chain but that’s it, and once over 30mph, all you get is wind noise. What you miss in the sound of a thumping four-stroke single, you gain in being able to hear what’s going on around you, especially in traffic.

The power delivery works well around town: performance was enough for mid-town traffic, and is very controllable, with the smoothest, most gentle of pick-ups from less than walking pace. The Bullet is a small, slim bike by modern standards, so it’s easy to filter through traffic.  With such easy power delivery, this would make be a great learner’s bike, and by the same token, the low speeds power delivery would make this a decent trials bike. Out of town, the e-Bullet accelerates up to an indicated 55mph, though it felt slightly faster, and it’s happy to cruise at 40-50mph.  This was the right speed for the Herefordshire lanes and quiet roads I was riding on, and it was all very restful. An adrenal-booster this is not.

Not the most beautiful of conversions, and examples like this have been built since the 1920s, as batteries and electric motors grew more powerful. [Peter Henshaw]
Electric motors have very little engine braking, but the Bullet does have regenerative braking, which switched the motor into a generator, directing braking energy into the batteries by drawing current to  slow down.  While taht sounds like a path to perpetual motion, in practice regenerative braking replaces only a fraction of the energy of forward motion, adding 5-10% to the total range in hilly country.  I’d have preferred this bike’s system to work through the rear brake pedal or reversible twistgrip, than the separate ‘regen’ button installed.

If you like Royal Enfield Bullets, this one handles like all the others. At around 180kg, it weighs about the same as the 350cc original, and weight distribution isn’t much different either. That translates into good steering and secure handling on its Avon tires, with no twitching, wallowing or other unpleasant stuff. The drum brakes are pure ’60s classic, which means you get a progressive but not very strong rear brake and an OK front. It’s also worth reminding yourself there’s no big four-stroke single engine braking.

That looks familiar. But what’s the meter on the left? [Peter Henshaw]
As with any battery-powered device, the crucial question is, how far can I ride? Fred reckons on a realistic range of 40-50miles, and after I’d ridden 31 miles over a real mix of urban and open roads, the state of charge meter was showing just over 25% battery left. So 40 miles to flat looks realistic, and more for urban use.  That’s not far, but realistically enough for commuting or Sunday pleasure rides. And remember, Fred has ridden this bike from Lands End to John ‘O Groats: all over the world, the network of charging points is growing fast, and it’s getting easier every year to make long trips on e-bikes. A full charge takes four hours on a standard charger, or two hours on a faster one. So you can’t cover 300 miles a day, but for commuting, or the typical classic bike ride of 30 miles to a pub and topping-up the battery over a leisurely lunch, it would do. In the UK a full recharge costs about £1 at domestic rates, so the e-Bullet would also be cheap to run – it’s giving the equivalent of 350mpg.

The juice: thanks Nissan for producing millions of these. [Peter Henshaw]
I liked the Charging Bullet. It’s very well engineered, works well and would make a practical classic commuter, though if you want a turn-key conversion it’s certainly not cheap. With the big squared-off boxes it looks a bit like prototype rather than a production bike: a period fairing or false fuel tank covering the boxes would go a long way to improve the looks. Then again, the bike isn’t pretending to be something it’s not. Otherwise, an electric classic could well be the way to keep riding old bikes, especially in cities which are increasingly likely to ban ICE cars and bikes in the not too distant future. The Charging Bullet is one option for future-proofing our heritage.

Would you like one?

Fred Spaven is now offering the Charging Bullet as a conversion to customer bikes, at around £7000. A more affordable option is a kit of parts which owners can fit themselves. ‘I would supply the subframe, adaptor plate, plus boxes for the batteries and electronics,’ says Fred, ‘and tell customers where they can buy the motor, batteries, controller and so on. Then I’d offer as much advice as they need to put it together.’ He stresses that there’s no cutting and shutting of the original bike, and that it’s completely reversible.

Is it missing the point?

Surely the whole point of a bike like the Bullet is the visceral feel of its thumping petrol-powered single and the way you interact with it via the clutch, four-speed gearbox and twistgrip. Next to that, some would say, the electric version has lost its four-stroke soul. As the owner of a diesel-powered Bullet, I can understand that, and the Charging Bullet, seamless and silent as it is, does lack the ICE sounds, smell and feel that we all love.

The logo: you can order or build one too! [Peter Henshaw]
But look at the way the world’s going. Many countries have pledged to ban new ICE sales within the next 10-20 years. Major cities are looking to ban their use altogether, and with the overwhelming scientific evidence on urban air quality and global climate change, that’s hard to argue against. There’s no doubt that as mainstream ICE use tails off, we’ll be able to carry on using our old classics, albeit with restrictions on fuel, mileage and where we can ride them. In that scenario, the Charging Bullet offers the chance to carry on riding an old bike as much as you want.

What it’s all about. Changes are coming: you can kick and scream, but government regulations will definitely affect vintage riders too. The Charging Bullet is one adaptation strategy. [Peter Henshaw]

 

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