Update: My bike continued happily with its weird, never-quite-off light until this weekend. On Friday I tried, for the first time in probably 5 or 6 months, to charge first my phone, and then a cache battery using my Luxos U. The phone didn't seem to be charging properly with the inconsistent power output, so I switched to the more forgiving battery. Batter blinked it's charging sequence for a while. The Luxos U switch showed red (for cache batter full, I think) for a while, then the red light went to blinking, and then it went off. And nothing has worked since then. The light continued to have that slight, never-quite-off glow until at least Sunday night. I haven't checked since then. The red, cache light battery never returned on a 40+ mile ride home on Monday, and the headlight has ceased to function. Changed front wheels to make sure the generator hub was not at fault, but, no, it's the light. It's not passing power through to the tail light, either. I think the tail light has protection against over-volting, so I can wire my tail light directly to it while looking for a new headlight and continue to get some use out of the set-up. Or maybe if I bypass the switch, I can get the headlight working again? Not sure, but going forward I won't try another headlight/USB combo solution. It leaves me with two things to replace at once when it fails.