At some point I found a system where both the rear and front light was not powered by internal batteries, but by a battery pack. For the life of me, I haven't been able to find it since. I'd really like to buy a front and rear from them.
Failing that, I wondered if I could buy some Kellermann Atto lights to run them on 5v (2.4A output), but they have never replied to my requests if they could run on 5 volts. I bet they think I'm pulling their legs. Nothing about voltage in their documents available online.
