You never know where you'll be getting your power from in a survival situation. More often than not, it won't be from a regular old outlet, so Instructables user Noise Maker decided to make a universal charger that can pull power from just about any source.
Using a voltage regulator, a USB jack, an old USB charger, and a few other parts, Noise Maker built a USB charger that plugs into the power source with clips instead of a plug. After a lot of tinkering and soldering of parts, the charger uses alligator clips so it can plug into batteries, solar chargers, and just about anything else that has at least 7 volts going through it. You certainly don't want to use it all the time, but it'll make a good addition to your survival gear.