I bought a Cycle2Charge. It was hung up in US Customs for around a month, and when it finally arrived at my house USPS had destroyed the box and repackaged it in an apology bag. Seems to work fine, though. I already had a small Coaxial power socket that I had used for the USB-werk, so installation was easy. I’m keeping the Cycle2Charge in my handlebar bag.

Now I’m looking for an inexpensive and light battery to use in pass through mode.

As far as wiring goes, my rear light uses a single strand of the B&M wire, routed through the rolled edge of the Honjo Fender. The neutral connection is through the frame and fender. This has given me zero problems. The wiring to the front light was glued inside the front fender, originally with two separate 2-conductor wires (one feeding the headlight, and the other going back to the taillight). I put silicone caulk over the wires to protect them; this was a big mistake. The caulk makes the wires impossible to maintain: you can’t remove it, and nothing will stick to it, not even more caulk. Don’t try this at home!

If I were doing this over from scratch, I would run two single conductor wires inside the rolled edge of the front fender, one on each side: one wire to feed the headlight, and the other to go back to the taillight. The fender itself would be the neutral.

Connectors to the hub and the rear light wire are hidden in the bottom of the head tube. With my headset, tying the neutral to the front fender grounds the whole frame; YMMV.