External buttons, connectors, LEDs, wires

From left to right:

• rubber pads (from a rubber tape), to be glued on the back of PCB pieces, on which connectors and LEDs are soldered - to keep the PCBs from sliding on the handlebar
• above - info-LEDs, below - connectors
• rubber pad to place under the button, and a finished button
• above - black covers, below - plastic cover - because the button's pressing head is small
• buttons not yet finished

Soldered it all with a single-thread wire (blue - because I didn't have black). Multiple-thread wire is poorly suited - it breaks off at the place of soldering.

Everything is winded to the handlebar with a thin (30AWG) black wire.

Connectors should be covered with some putty - I had glitches under rain. Button's contacts are spaced far from each other, so should be OK.

Brake light buttons are glued (with "Moment") to the brake lever housing via such a tin holder:

Misc

If power wires are long, it makes sense to take them thick - to make resistance (and voltage drop) smaller.

I re-soldered original lithium-ion battery from the Xeccon S14T light (it was 2S), so there's no protection board anymore. This is dangerous - lithium! (some other cautions on CPF). So I protected it with a fuse. I made one myself by cutting a very thin stripe from a flattened piece of tin (whatever they use) from a 20A-fuse.