Originally Posted by LeeG

$.02 dynos are great for commuter bike lights. Always there and reliable. I have them on both my bikes.
For touring on a budget I'd be inclined to stick with an extra battery pack and use devices judiciously. Batteries can be rechargeable like your phone. Nighttime riding is unlikely while touring and batteries last a long time in tailights.
That said it's good info hearing from folks who use theirs for charging a battery or phone.