Solar charger for iPhone whilst on a bike tour - is it worth it? Are there any feasible solar chargers for iPhone / or with a usb slot that will work or is a backup battery available. Best value (and something that works) is my priority. I found this brilliant link on crazy guy on a bike- http://www.crazyguyonabike.com/doc/?doc_id=9258 However, since then I came accross 'portopow' http://www.portablepowersupplies.co.uk/ - which look great but I can barely find any reviews.
I have actually used both 2 different sized solar panels and a lithium backup battery on Ragbrai. Whether any of these will work for you depends on:


How many days long is your ride?
How sunny will it be and how much time will you have to do a solar charge?
How many devices you need to charge.


For solar charging. The first lesson is you can not charge your device with a solar panel while you are riding. Solar panels need to be pointed directly at the sun to provide any kind of real power. The little solar chargers you see advertised are utterly useless. They might charge a phone if they were pointed directly at the sun for an entire day (15 hours). The larger solar charger I have is 14" x 12" with an adjustable mount so you can keep it aimed at the sun. I could recharge my phone (when off) in 4 - 5 hours.

Small charger (useless)

10 watt panel (works)

What worked the best was a large backup battery. They are not physically large- just large capacity. (15,000mAh or more). I used this for an entire Ragbrai. It charged my phone once a day for 9 days with power to spare. Note you turn your phone off at night, plug it into the charger, and the charger automatically turns off when the phone is charged. The phone saves power by being off all night. Wake up, turn the phone on and it's good for the entire day and evening.

Sample 15,000mAh battery

You can fly with these batteries in your luggage and probably in your carry on luggage. But the TSA often makes up its own rules on the fly and might decide to confiscate one in your carry on. I would keep it in checked bags.

TSA rules

Note that it takes about 2 full days to charge one of these batteries. You should probably test charging all your devices at home to see whether you can make it on your trip. You also need to remember that your battery is just as dangerous as an equivalent sized container of gasoline. You do not want to puncture it or expose it to high heat.

If all that information is confusing, I only take my backup battery on Ragbrai now.