HPV Scorpion FS20 e-conversion

In January 2017 I set about electrifying my HPV Scorpion FS20 recumbent trike. Trikes are great fun to ride, and comfortable too. A lower profile and recumbent position mean they are more aerodynamic, but the downside is their weight. For me, it makes any climb hard going, even pretty innocuous lumps can take some effort. Of course, you can grind away in an ultra-low gear and, with three wheels to keep you upright, you can go as slow as you need to.

After looking at the options of a wheel drive or crank drive, I opted for a crank drive. Wheel drive kits tend to be cheaper than crank drives, but I find the crank drive a more elegant solution. And, If I ever wanted to sell the trike, I could remove the kit, revert the trike and fit the kit to a different bike, regardless of wheel-size. A crank drive will only have a single chainring, but my trike had that already, so it meant I could retain all 27 gears – a 3-speed rear hub gear with a 9-speed cassette fitted.

A Bafang seemed to be the obvious choice. Buying from China, where they are made, is a lot cheaper than sourcing one in the UK or Europe – there are plenty of providers on Amazon but the disadvantage is delivery times are much longer. As I was a bit sceptical about buying direct, I ordered a kit including a 15Ah battery from Woosh Bikes in the UK.

The Bafang kit is very comprehensive and easy to install, thanks to the fool-proof connectors. Instructions are not really needed, which is probably a good thing, as there weren’t any. For those that are doubtful, there are plenty of videos on Youtube about how to install a Bafang…on an upright.

The 250W Bafang crank drive kit laid out. Closest are the chainring cover, cranks and charger. Behind, the motor, spacers, battery with mounting bracket and locking key. Ay the back the thumb throttle, brake levers with sensors and the speed sensor are all connected to the display which has the control buttons permanently wired into it. Excuse the table cloth – I like to keep my workbench looking nice πŸ˜‰
The old BB – a bugger to get out!

First job was the remove the current bottom bracket from the trike. And there I hit the only real problem I had. Even with the right tools, I could not loosen it, so took the bike up the road to my local bike shop, where they dealt with it straight away.

To make working on the trike easier, I made use of our garden table and an axle stand.
NOTE: If you want to be able to fold the trike after fitting, make sure there’s enough slack in the cabling to allow for the fold.
Once the trike’s bottom bracket is removed, the motor with bottom bracket attached slides in from the drive-side. There’s a retaining bracket to stop the motor rotating within the bb shell and a lockring. Then the chainring and cranks can be fitted.
The motor is a 250W one – the lowest power Bafang make, but the only one legal in the UK. Also to be legal you should not have a throttle that can drive the bike without pedalling, and the power must cut out at speeds above 25kmh/15.5mph.
I wanted the battery hidden, mounted on the rear rack, so I fixed the battery mounting bracket through the bottom of a rack-bag, using a piece of plywood to the rack to fix the retaining screws into. The bag is supple enough to allow me to slide the battery off it’s mounting bracket and remove for charging and storage. There’s room down either side of the battery for some bits, like tubes and a waterproof etc. This battery has a USB socket, so I ran a 2 metre Apple iPhone charging lead from the bag to the front of the trike along with the power supply.
The underside of the rack, showing the wooden mounting ‘plate’ fitting.
As the kit is designed for conventional uprights, the wiring to the battery needed extending.
The left hand steerer. The control button cable also needed extending, as I wanted the display mounted centrally near the front of the boom. Fortunately, the trike had cable operated brakes, so I could use the levers that came with the kit. They have sensors in to cut the power when either or both brakes are applied. If you have hydraulic brakes, you’ll need to buy brake sensors to fix to the hydraulic brake levers.
I mounted the thumb throttle on the right-hand steerer. On the mudguard mount, on the left wheel is the speed sensor. Similar to a trip computer fitting, with a magnet fitted to one of the spokes, this small item needs to work perfectly. If the magnet or sensor move, and stop working, the motor will only provide power for a couple of minutes, then it will shut-down.
I have since moved the sensor to the small bracket on the steering arm close to the reflector.
There is quite a bit of wiring to keep tidy but a lot is hidden by the seat once fitted. I used lengths of cable management to keep the cables together. I got mine from Maplin, but there’s plenty on Amazon.
Once it was all connected, I tested the unit before tidying all the wiring. To fix the display I used on old stem mounted onto the gear stump with a section of unused handlebar I cut down but have since put a lighter handlebar accessory mount in its place.
Lots of zip-ties – but they do the job.
Everything in place, I used bar-tape over the cables and wires to finish off the bars.

On my first ride out, the motor rotated within the bb shell, even though I thought I had it tight. That pulled on the cable and pulled the main connector apart, and I lost drive. It didn’t take long to sort out.

Since putting it together I’ve ridden several hundred miles without any real issues, though the connection (my extender) to the speed sensor became erratic because it had worked loose, so I soldered the joins rather than just wrapping them… something I should have done in the first place. For the larger cable extension I used plastic-housed screw connectors and wrapped all the connections in waterproof tape.

The trike in its form as at June 2020. I added an Airzound airhorn as I had one lying unused in the shed, but I also kept the bell for friendlier encounters, as the Airzound is loud and aggressive. Generally drivers give me a lot more space and consideration on the trike compared to any of our uprights.
The Airzound is mounted to one of the seat tubes and the air tube has enough slack to flex with the steering.
I mounted a small frame-bag on the boom to house my iPhone when riding, which is kept charged by a cable back to the USB socket on the battery.
The arrangement at the front, with a plastic bar accessory mount holding the display. The headlight is connected to a bottle dynamo on the back wheel and the cable runs inside frame and boom.
The flag is home-made. I bought some lengths of bright ribbon through Amazon and stitched them to a small plastic flag (also from Amazon) that is meant for kiddies bikes.

Pino e-conversion

After coming back from a long tour of France I decided it was time to put a motor on the Pino. I had mulled it over for some time and, because a new ‘e-pino’ is horrendously expensive, I decided to fit a Bafang Crank Motor.

I bought the motor and battery together, from ‘Aliexpress.com’ and ordered it from China, as it’s cheaper than using a European supplier, but delivery times are longer. If you are in a hurry for the kit, a UK or European supplier will get it to you sooner.

This kit went onto my recumbent trike, but the Pino kit was identical except for the battery, which was a little bigger at 17.5Ah

The hardest part was getting the old BB out – it had been on the bike since 2011. I swapped the stock control display unit for a SW102 combined controller/display which is very small and sits neatly at the bar-end. I also had to fit hydraulic brake sensors (bought at the same time) and I fitted the plain, right-hand crank from a Thorn Tandem ‘Captain’s’ crankset from SJS Cycles. The total bill was around Β£700.

Fresh back from a ride, so it’s not clean – the left-hand Hase crank with freewheel and the motor sitting under the BB shell.

The Hase crank has a square taper axle – in what I call a ‘square, square’ pattern. The Bafang cranks supplied in the kit are ‘square, diamond’ pattern, so, in order to retain the Hase freewheel, you need to source a ‘square, square’ right hand crank. These are available as a Tandem Captain’s crankset from SJS Cycles. You will have to buy the crankset, as they don’t sell individual R/H cranks.

The ‘Square, square’ hole in the Thorn crank matches the hole pattern in the Hase Pino freewheel crank. Our Pino is 2011. Hase may now use a different crankset, so it’s worth checking before you buy.

The Thorn, right-hand crank from SJS Cycles and the 46T covered chainring. You can specify different sized chainrings but we’ve found, coupled to a Rohloff with 15T sprocket, it’s a good size that allows us to climb well and keep pedalling up to 25-30mph.
The 17.5Ah battery bought with the kit. The battery doesn’t have an ‘off’ switch or a USB socket. Both features worth having I think, so it may be a good idea to buy the battery separately from the kit, or make sure these features are on the battery. The battery locks into place on the mounting bracket with a key.
The mounting plate for the battery. There was more than enough power cable, so I shortened it to fit the layout better.
Right side of battery showing charging port. This is quite a large battery at 17.5 Ah but there’s enough room to slide the battery off the mount to remove for charging indoors.
Mounting plate from right side. There’s a bottle cage mount on the frame (under the black cover on the bracket), that can be used to mount the bracket. I had to drill a couple of holes in the bracket, to allow it to be fitted using the holes in the frame and sit in the correct position. A zip-tie keeps the front end tight.

The power supply cable runs out of the rear of the battery mount and behind, then under the BB shell.
Rohloff hub with chain tensioner. Chain alignment is pretty good.
Please excuse the grotty Ergon Grips – that’s 9 year’s worth of accumulated gunge.
The SW102 controller/display. This is not the standard display and separate controller that comes with most kits. I added the lumps to the buttons, as selecting up/down on the unmodified rocker switch was tricky with gloves on. The cable runs along the underside of the grip, but it could go down the inside of the bars for a tidy look, but you will need extensions to do so.
Since the first photo, I added some padding in the form of a chopped up handlebar grip to cover the brake clamp, which I found irritating on long rides. I am going to do the job properly using bar tape.
The thumb-throttle at the end of the bars – handy for pulling away on hill-starts or from junctions. Again, the cable runs along the underside of the grip. The Rohloff gear selector is a left-hand one which I find works well where it is mounted.
We have a hub dynamo on the front wheel, to which we connected a Busch & Muller Lumotec IQ2 Luxos headlamp. This has a USB outlet, so I have run a charging cable from that to the handlebar, to keep my phone charged while I use it to track rides and navigate. The waterproof bag is a Topeak dry bag.
The magnet mounted to the brake lever and the sensor, mounted to the brake lever body so that pulling on the brakes cuts the power to the motor. I used the very useful mouldable glue ‘Sugru’ for the job. It sets in about 24 hours, so a little tape was necessary to keep all in place while the glue set. The brake sensors were extra, but the cables fit in place of the cable brake levers supplied with the kit. All the cables on the kit have different colours for matching male/female connectors as well as different pin patterns, so it’s pretty well impossible to make a wrong connection.
The wheel sensor and magnet on the rear wheel. These need to be fitted and aligned well, as if they don’t work, the motor will cut out after a couple of minutes if it’s not registering any rotation.

This may all look a bit complicated, but I am no mechanic or engineer, and I have fitted two of these motors now. As I said at the start, the hardest part can be removing the old BB.

Christmas 2019

Enjoying the August sunshine of southern france, near Marciac at the International Tandem Rally 2019.

Two and a half years into retirement and we are coping well. We celebrated no more work with a month of tandeming in Germany, down the Rhine, a week with the International Tandem Rally in Oberhausen an der Nahe, then cycling up to Lippstadt for an Army reunion, after which we headed back to the Rhine and followed it downstream to the Hook of Holland and the ferry.

Last year it was Sweden, but a bit too far to cycle we thought, so we drove, stopping in each place for a couple of nights so we could have a day ride before moving on. Sweden was fun with unusually warm weather – which was good – and the island of Γ–land perfect for riding, though the headwinds were a bit grueling at times.

In December 2018 I was fitted with a pacemaker. After a few years of bradycardia and arrhythmia the docs decided it was time. It took a while to get right, but now it’s settled and I’ve got used to it, I forget it’s there most of the time.

In spring 2019 we headed back to Germany to join Tandemtreffen (TT) for a weekend of tandeming. This was our second TT and just as much fun as the first. We hope to go again in 2020, which will be in the area near the Mosel river.

In the summer of 2019 we set off from home on the 1st July for an epic tour of France, riding to the Mediterranean and on to Toulouse before picking up a car to carry on the the International Tandem Rally at Marciac. After an enjoyable week of cycling within sight of the Pyrenees, we drove back to Caen, dropped the car off and caught an overnight ferry home.

As winter takes a firm grip and Brexit looms, I wonder what will pan out for us in the next few years.