I haven't used it for cycling, at least yet but I have had success camping. The last two years I used a goal zero Venture 30 and nomad solar panel at my sons Cub scout camp Venture 30 Solar Recharging Kit | | Goal Zero

4 days total. I made it without needing to plug in. I kept the panel clipped to my daypack. Granted this isn't like hiking, as the scouts had lots of activity stations throughout the day, so it would be easy to leave my pack in the sun while these sessions were running. I would imagine on the back of the bike it would get pretty good sun as well. The venture 30 can charge my iphone about 2.5 times and it recharged in about a day of good sun. 2 years in a row I never had to plug my phone into an outlet to charge.