We have recently started stocking the Sinewave Reactor dynamo-powered USB charger. The charger is made in the U.S. by a company out of Massachusetts called Sinewave Cycles. We really like the design for a couple of reasons.
First of all, it’s 100% waterproof. All of the electronics inside of the charger are completely encapsulated in epoxy, and the USB connector itself features gold-plated connectors that will not corrode. The epoxy inside the charger also protects the electronics from being jostled and ensures that the system can withstand any sort of rough roads or mountain biking that you throw at it.
Also, we like how low profile the cap is that extends above your stem. The system uses a traditional star fangled nut, and is easy to install and maintain. It will work with any brand of generator hub (Shimano, Shutter Precision, Schmidt, Sanyo). Power generation starts at 3.5 mph, hits 500 mA (standard for a wall mounted USB charger) at 9 mph, and tops out at 1A at 18 mph, which means that as long as you are riding at above 9 mph you are getting the same or more amount of charge as if you were plugged into a wall. Pretty sweet! Definitely the best system that we have seen.
The Reactor charger is $220, and is available in black, red, or silver. We also stock Shutter Precision hubs, which we feel is the best tradeoff between weight, cost, and drag. At $130 for a hub, you can have a solid, handbuilt wheel rolling for under $250, and the whole system for under $500.