Electrification & Restoration of a 1970's Raleigh Shopper

This Instructable is a rags to riches story.

I have taken a 1970's Raleigh Shopper/20 bicycle and converted it into an electric bicycle via a 1000W rear hub.

I came across this bicycle when I was helping a fellow construction worker in clearing out his father-in-law's house. As expected the first reaction of the member of the Generation-X club was to chuck it out and inevitably revert to their Thatcher firmware of consumerism when a bike was needed. As a Millennial, I thought it was a perfect opportunity to prove to Generation-X that everything that glitters is gold!

As a keen cyclist, I've had a certain soft spot for the Raleigh corporation and I was lucky enough to have stayed in a flat converted from one of their old factory buildings when at university. The 'Frame Production' (A book documenting Raleigh from an industrial, social & technical background) was also one of the first books that drew me into the world of design thinking.

It's also fitting that a bike's design, which some accredit to the end of the British Cycle Industry, might help revive its reintroduction with the aid of a battery.

Step 1: Dissassembly

This part of the project was straight forward.

Just take everything apart on the bike.

Remember to keep every nut, bolt, and washer. The older Raleigh bikes use the British Small Arms Standards (BSA).

Depending on the condition you'll have to contemplate whether to upgrade or restore.

I also can't stress enough how great a resource the https://www.sheldonbrown.com/raleigh-twenty.html

This guy has written in great detail about the bike, including upgrades, modernization, and restoration.

Step 2: Paint & Rust Removal

In this part of the project we will prepare the individual components. We can split the components into two
groups - Chrome parts and Steel parts.

Chrome Parts

Dip aluminum foil into clean water. Water (with a little salt added) works best, as the salts and electrolytes in the water can help to speed up the chemical reaction. Tear small strips of foil to use on rusted chrome areas. You can finish the chrome by using some polish to enhance and protect the parts.

I was surprised at how great the results were from what I initially thought might be parts destined for the bin.

Painted Steel Parts

This is a two-process technique.

Firstly, we will use a brand named substance called Nitro Mors, This acts as a paint remover and helps remove the majority of the paint. I'd recommend following the user guide on the tin and prepare for a mess. Once you've removed the majority of paint the hard work will really begin.

This step will take you a day or two to get a nice finish. The step itself is relatively easy, you simply rub-down the painted steel parts with medium grit wet and dry paper until you're back to the glorious steel.

Step 3: Cold Setting and Grinding the Dropouts

This step could potentially be seen as the make or brake step.

I'd only been able to spec an electric rear hub that had an axle diameter of 130mm. The shopper/20 has a spacing of 114mm for the rear hub, so the plan was to cold set this to 130mm.

I'd say this was pushing the adjustment to its limits, as more would begin to create a problem with the pedals crank arms.

I used a method of inserting a M8 threaded rod through the axle (which included bolts) and slowly tightened them out over a couple of checks until I was as close as I'd dare to 130mm.

I then repeated the same process on the forks, which need to be 100mm. The 8mm axles slots were next to be tripped.

I decided to shave off 2mm by gently stroking the axles bottom drop out until the 10mm gap was achieved.

I then repeated the process once again on the front fork.

And that is the frame alterations required for the upgraded wheels.

Step 4: Frame Painting & Glossing

The painting process is an extremely difficult process to obtain a professional result.

The key is surface perpetration - before and between coats - and an even coating process.

I was semi-happy with the results but the finished still suffered from orange peel, I found it difficult to sand evenly between the tubing.

Start by rubbing the frame down with rubbing alcohol to remove any dust and grease accumulated from the hands and sanding process. Remember to wear gloves throughout these processes.

The Primer coat is used to protect the metal and help smooth imperfections. It also acts as a absorbing layer for the colour to be applied.

Metal Primer (https://www.fatbuddhastore.com/montana-t2400-metal...)

I applied a thick first layer, then once dried I lightly sanded and removed the dust with a damp cloth. I then went back to the dried surface for a lighter coat. Finally, I repeated the process but with the lightest of sands - 2400 grit and cleaned the surface.

I repeated the same process with Colour Layer (https://www.fatbuddhastore.com/montana-black-blk90...)

Once I was happy with the coating, I applied a gloss layer with a hardener to help protect the paint as the final process.

Spray Max 2K HIGH GLOSS Clear coat Lacquer Spray 400ml

Step 5: Reassembly of the Painted Frame

Step 5. Begin the Reassembly of the Bike.

Attach front fork and handlebars using the nylon type bearing and the chrome bottom bearing and then tighten as required
1. Remember to grease everything accordingly as you go.
2. Also please refer to Sheldon's website listed above for help.
You can also attach the seat post and use this to support the bike if you've got a bike stand.

Sheldon also goes as far as to total upgrade the front forks because of the inferior nylon bearing system.

Step 6: New Brake's + 20in Brake Dropdown 3D Print

Custom Parts.

Because I could only spec a 20in electric rear hub I had to solve the issue of the reach of the brakes.

This could have been achieved in a few ways. I ended up deciding to upgrade the caliper brakes and solve the reach issue. This resulted in firstly ordering long drop brakes.

Spec'd with a reach of 47mm to 59mm

Tekro R539 Caliper Brakes https://www.wiggle.co.uk/tektro-r539-long-drop-roa...

However, I also needed to create a custom bracket to drop the attachment point further.

I did this by 3D printing PETG parts with metal inserts to act as a new bracket for the brakes.

Please see the attached STL

Step 7: Attaching the Electric Wheel

We can now begin to start to attach the electric bike kit from Voilamart!

The first step is to buy and attach a single speed free-hub. I selected a 16 teeth hub.

Then you can attach the back wheel into the axle that had been widened when we were preparing the frame earlier.

This should slide in tightly and then you can attach a locking washer.

As a further safety measure I attached a torque arm to both sides of the axle. This is to do with the torque affect of the motor and the resulting force generated in the opposite direction that can break the dropouts as a non designed force is applied to it.

Torque Arm https://www.amazon.co.uk/RICETOO-Electric-Bicycle-...

I also had to remove the connector to allow me to get the torque through the internal wiring of the motor on one side.

You can also loosely tighten the wheel now.

Step 8: Mounting the Electrical Components

This part is very straight forward. You are basically attaching the interface. I think every kit has a similar formula.

The main items to attach are the LCD, Twist Throttle, Menu Navigator.

Step 9: PAS Sensor

The PAS Sensor is used to measure the rider's cadence and help the power system understand how much extra power should be supplied to the motor to aid the rider.

https://www.sheldonbrown.com/cotters.html (Cotter Installation and Removal)

When I was installing it I noticed that the magnetic ring was too wide to allow the attachment of the cotter pin to lock the cranks back onto the bottom bracket.

As a result, I designed and printed a holder for the magnetic disk and modified it accordingly to fit.

Please find the STL file attached.

Step 10: Control Box Customization & Housing

I also decided to re-house the motor controller into a custom printed box because I felt it would add some extra protection that the supplied bag wasn't going to.

As you can see you can also mount this in a central area of the bike.

Please find attached the STL file.

I also changed the Positive and Negative battery connectors to an XT90, extending its reach to where the battery would fit.

I started by soldering the XT90 connector with 12 gauge silicone copper wire and then spliced this to the original wires.

I think Anti-Spark XT90 or XT60 Connectors would be the optimal solution for this application.

Step 11: 18650 Battery (48v - 15Ah)

Building a battery to power the 1000w rear hub motor.

First thing was to note that the motor required a 48 volts supply, so the battery I was to build had to supply a nominal Voltage of 48v.

I then also acknowledged that to run the motor at its maximum 1000w, the motor would draw a current 21 amps.

As a result, I was going to combine together 18650 cells to create a battery to deliver a nominal voltage of 48 volts and be able to supply a max current supply of 30A.

18650 were chosen because of their energy density, weight and charge/discharge rates. But each manufacturer of these cells produces differing specifications and models, key specs to consider were capacity, max discharge rating, reliability and cost.

Because my budget was limited I picked from a second-hand battery supplier on Ebay.

Link https://www.ebay.co.uk/itm/lots-100x-tested-18650-...

I chose the Sanyo - UR18650AA.

You can see the DATA sheet attached.

These cells like most 18650 cells have a nominal voltage of 3.6v.

This means if we divide 48v by 3.6v we get 13 (this means for our battery to obtain a nominal voltage of 48v we will have to wire 13 3.6v 18650 cells in series).

I then divided the 100 used cells I'd purchased from Ebay by 13 to give me 7 cells per stacks.

To the calculate a estimated capacity of the used cell, I timed 7 by 2300 then divided by 100 and timed by 90.

This gave me 14.5Ah of battery capacity.

It should be noted that these batteries were rated at 90% => capacity when tested. I'd say it was important to select batteries with similar remaining capacity to aid this unit's longevity when balancing the stack when charging and discharging.

Building the battery required some additional parts as followed:

XT90 & XT60 connectors to attach to the power input and charging input
A Battery Management System (BMS) (must be 13s-48v with 30A continuous output)

https://www.ebay.co.uk/itm/13S-48V-30A-Continuous-...

100% nickel strips for connecting the cells with
Gauge 10 silicone nickel wire

Tools Required

Spot Welder
Soldering Iron, Solder and Flux
Kapton Tape
Wire Strippers
Heat Shrinks
Hot Air Gun
Volt Meter
Glue Gun
Multi-tool with grinder on it
Plus a range of clamps and jigs to hold the cells while building the battery

Building the Battery

Creating an array of the battery on the computer to make 13 equal balanced stacks.

I did this by creating a reference for each cell and entering its associated capacity into an excel data sheet. I then ran this through a custom python programme using a box packing library to obtain 13 stacks of similar capacities. I then used the location references to pick the cells from during the building process.

Preparing the cells

Once I'd picked a group of 7 cell for a stack, I removed any nibs from the positive and negative ends (this is important to achieve a good weld between the cell and the nickel strips). I then cut the required nickel to size and clamped the group into position, being careful to check the positive and negative were correctly matched.

Welding the cells array together

Begin by familiarizing yourself with the spot welder, make sure you get the right pulse setting that creates a strong weld but doesn't blow a hole into the cell. I'd suggest testing it on a spare cell until you have the right setting, where the nickel becomes difficult to remove from the cell. You then need to work your way through, combining the cells together into the designed array. Make sure to cover the sections you've complete with kapton tape as you go to prevent any accidental sorting (I've done this and it's quite a spark!). For me, I'd clamp an opposing stack to the array and weld 6 spot onto each cell in the group. I'd then cover the section with kapton tape and then flip the battery and begin again.

Let me know if you need any more information!

Use a voltmeter to test the pack as you go!

Adding the BMS

Electrically insulate the BMS from the battery. Then connect the two main positive and negative power lines to the separate ends of the battery. Once again be careful not to short the battery, so keep any bare wires covered in insulated tape. To connect the thick nickel wire, work along the end stacks of the tinned section and press the soldering iron quickly into place, holding until solid. Hold with something making sure not to heat damage the cells below by connecting the sections between the individual cells. Then connect the small wires to the corresponding sections to control the individual stacks.

The link below will help you understand the build process a lot better.

http://www.ebikeschool.com/how-to-build-a-diy-elec...

Adding the connectors

Add the connector to the wires and then splice them into the BMS as requires.

Test with a voltmeter and then charge to full capacity.

Now you should cover your battery in some yoga mat foam and shrink wrap it to help protect it against damage. then look for a suitable padded case and secure it tightly within.