Could a 12v 6w bicycle bottle generator be used to simultaneously charge two USB devices at 5v 3w?
I'm looking to power a few different USB devices while I ride my bicycle. Hub dynamos are typically 6v 3W AC, which makes them pretty conducive to USB which is 5v 3W DC, and there are some kits that do just that. However I've found a few bottle generators (the kind that run against the tire) that produce 12v 6W (I'm not sure, but I think they are DC). Now I'm no Nikola Tesla, but it seems to me that one of those could charge two USB devices at once. Either some kind of splitter or just a 12v battery with a USB hub.