I recently decided to upgrade the headlight on my Brompton Electric bike to the Cyo Premium E. I followed https://www.youtube.com/watch?v=osCbgMQwlY0 but found the video lacking in detail, so this guide goes into more depth on the parts and procedure needed.
The main difficulty with this upgrade is that the Cyo headlight does not come with the Molex connector used on the stock Brompton headlight, so you'll need to either install the connector on the new light yourself, or remove both sides of the original connector and solder the wires together. I went with the former approach, as I found it a bit "cleaner", and avoids modifying the battery side of the wiring.
- Molex Micro-Fit 3.0 Receptacle Housing, 1x2 x 1
- Molex Micro-Fit 3.0 Crimp Terminal, Female x 2
- Open barrel crimp tool
- Wire strippers
- Wire cutters/scissors
- 4mm hex key wrench
- 10mm/adjustable wrench
- Torx screwdriver
I would strongly recommend getting spares of the Molex parts, especially if it's your first time crimping; I went through more than 10 terminals before getting it right. Get extra housings too, as you will be unable to extract the terminals once you install them (unless you have a special removal tool, but it's much easier and cheaper to just get spares).
Also, you must use an open barrel crimp tool; regular (closed barrel) crimp tools will not work! Look for something which has a 1.4-1.8mm die width - I used the Engineer PA-21 but any open barrel crimp tool with the right die size should work.
Follow the steps in https://www.youtube.com/watch?v=osCbgMQwlY0 (starting from 8:18) to disconnect the old headlight from the bike.
Like in the video, we'll be reusing the insulation from the old headlight. Cut off the Molex connector from the old headlight, and transfer the tube and gasket onto the long wires of the new headlight (the short wires connect the headlight to the rear facing light - ignore those for now). Trim the long wires to approximately the same length as those on the old headlight, leaving 2-3 inches of excess in case you need to redo the connector (trust me, you will).
Next, crimp the terminals onto the wires. I'd strongly suggest watching a video tutorial on how to do this properly - https://www.youtube.com/watch?v=GJqt5VYRBro is pretty good. Make sure to use the appropriate width on your crimp tool for the connector - for me, that was 1.6mm. Give the wires a good tug to ensure that they are securely crimped in place.
Make sure you get the orientation of the terminals right - when the crimp is facing "up", you want the wire with the white stripe to be on the "right" side (if you got it backwards, just twist the wires around). Then, insert the connectors into the housing, with the crimp facing "up" (towards the locking tab), until you hear them click into place.
Finally, reinstall the headlight onto the bike. Connect the short wires from the headlight to the rear facing light - the white wire connects to the red connector. Install the battery and make sure everything works, then screw everything back together and you're done!
