Andrej Shadura: Connecting lights to a Swytch e-bike kit
Last year I purchased an e-bike upgrade kit for my mother in law. We decided to install it on a bicycle she originally bought back in the 80s, which I fixed and refurbished a couple of years ago and used until September 2022 when I bought myself a Dutch Cortina U4.
When I used this bicycle, I installed a lightweight Shutter Precision dynamo hub and compatible lights, XLC at the front, B chel at the back. Unfortunately, since Swytch is a front wheel with a built-in electric motor, these lights don t have a dynamo to connect to anymore, and Swytch doesn t have a dedicated connector for lights. I tried asking the manufacturer for more documentation or schematics, but they refused to do so.
Luckily, a Canadian member of the Pedelecs forum managed to reverse-engineer the Swytch connector pinouts, which gave me an idea on how to proceed. Unfortunately, that meant that I had to replace both lights, and by trial and error I found specific models that worked. Before the Axa lights, I also tried B chel s Tivoli e-bike light, but it didn t work because the voltage was too low:
Once I knew what to do, the rest was super easy
So, here we go:
- Get a 3-pin (yellow) male connector with a cable, e.g. off AliExpress. Only two wires will be used, the white one is +4.2V (4-point-2, not 42!), the black one is earth. This will go into the throttle port. If you actually have a throttle, you need some sort of Y-splitter, but I don t, so this was not an issue for me. (However, I bought both sides (M and F), just to be sure.)
- Purchase an Axa 606 E6-48 front light. The 606 comes in two versions, for dynamos and e-bikes, use the one for e-bikes; despite being officially rated as 6 48V, these lights work quite well off 4.2V too.
- Purchase an Axa Spark Steady rear light. This light works with both AC and DC (just like the 606, the official rating is 6 48V), and works off 4.2V without an issue.
- Wire lights up. I used tiny wire terminals to join the wires, but I m sure there are better options too. Insulate them well, make sure the red wire from the throttle connector is insulated too. I used a bunch of shrink tubes and black insulation tape. Since the voltage is not wildly different from what the dynamo hub produced (although AC, not DC), I was able to reuse the cable I had already routed to the rear carrier.
- Lights go on automatically as soon as you touch the power button on the battery pack, and stay on until the battery pack is switched off completely. I was considering adding a handlebar switch, but since I lost the only one I had, I had to do without.