A couple of things found (a Topsy, for example, “runs for 7 hours on a 12 volt 30 AH battery“):
- http://www.mark-ju.net/bike_ride/equipment/charger.htm charges stack of 6Vs
- For about the same weight as a generator setup, you could get a solar charger that works whether you
are pedaling or not. Batteries.com has one that weighs .28 pounds and will charge 4 AAs in “as
little as 12 hours of direct sun” and costs 20 bucks.
- http://geektechnique.org/projectlab/511 Bike-charger for iPod
- http://geektechnique.org/projectlab/236 previous hand crank version
Trad dynamo setup = easier initial setup but less reliable