I use this system: ($30)

http://www.thinkbiologic.com/product...icro-usb-cable




Note: I bought an older version of this unit that came with DC style plug, I cut off the plug and soldered on a standard USB female. (heat shrink tube on connector) The output is 0.5 amps.

With the appropriate patch cord (micro USB now included in kit!) I can charge a 4x18560 battery pack (7$) or my smart phone.

My weather protection is minimal, It hangs behind a handlebar bag with an dummy USB plugged into it. I think I could put a slice of inner tube around it to keep it dry but have not done so yet.

The female USB was around $1 from fleabay. The bioloigic recharge was $25 at the time.

I run it parallel with my light. The positives are twisted togehter and the negatives twisted together and then plugged into dynamo hub. When light is on they share the output. When the light is off Biologic unit receives all power.

This is on my daily, all weather commuter bike, and I have not really used it that much. Mostly done for an anticipated tour.

If funds were available, I would have liked to try this unit.

http://www.amazon.com/LightCharge-Bi...rds=dynamo+usb

rather than hack my own. It does not put out any more power but has its own off/on switch and a rubber boot for the connector.