How to charge my iPhone 5 without any electricity?

I'm going to a music festival for four days and am needing my iPhone 5 all four days. We do not have any electricity or cigarette lighters in the car. What is the best product like a portable external battery would give my phone enough battery life for 4 days and isn't super expensive?

Mount a solar panel on the back and hold it above your head the entire time while waving your hands to the beat of the music.

Replacing the battery with liquid nitrogen should completely destroy the phone and result in you no longer having one. This will mean you don't have to worry about it being charged up.problem solved. Then sell it on ebay as used. No money spent on some portable charger you will never use again. And i have heard liquid nitrogen is great on pancakes.

Solar panels are coming in the market if you want to charge from solar energy than you can use them.