If you're planning to go camping or spend time on the road without your regular phone charge (electricity), now you have other option using Wind Up Phone charger. This is similar to the wind up flash light if you have it.
How to use it?
Turn this vigorously for a few minutes and the Wind Up Mobile Phone Charger creates enough energy to power your mobile for 25-30 minutes. It also has an inbuilt extra flashlight - so should you misplace anything you can find it again easily.
Gadgetshop is selling for £5.99 at this time. Go get one for yourself if you need it. It won't break your wallet.