One of the biggest problems with carrying around a mobile device is carrying around a charging cord that isn’t so portable. There is now a specially made charging cord from BiteMyApple known as the ChargeCard which is very easy to have on hand.
The ChargeCard is one of those devices that I wish I had thought of before. The Chargecard is about as thick as a two credit cards stacked together. It is not made for the outlet, but if you have a USB port handy, the Chargecard can give you that amount of juice that you need in a sticky situation.
You can see in the picture how flat it gets, but the USB male end goes into a USB port, and the one that I got to try out had a 30-pin connector for an iPhone 4/4S or earlier. I am told that the ChargeCard will work with larger and more protective cases.
You can get the ChargeCard on the BiteMyApple site, which is a site devoted to Kickstarter projects that work well with Apple products. The price is about $24.99, and you should look around and see what else you can find. A Micro USB version is coming soon, as is a version for the iPhone 5.