Please mention what kind of phone you are charging. I recently got my first Android phone (Motorola Electrify) and it barely turns after charging it for 8+ hours on a computer USB port after it was completely drained. I doubt a solar panel or hub dynamo could keep that phone charged. My old dumb phone charged really quickly on an computer USB port. The smart phone is probably one of the first things on my cut list for multiple day rides or hikes. Especially since the battery life is only one day vs. a week.