This is a belt consists of 8 stripped down JAPOD cellphone batteries. All the batteries are connected in parallel to have a total capacity of 10.8AH (not mAH!) at 3.7 volts. This belt could probably recharge a phone 6 or 7 times (i've never fully run down the belt, so I don't know) off of a single charge. The batteries are connected using a three conductor flexible ribbon from Sparkfun. One conductor is ground, another is Vbat, and the last one is Vusb. Each usb port has it's data pins bridged and is fed 2 volts via a voltage divider. Everything is covered up with a piece of fabric (that is starting to show wear) which is held on by rubber cement.
The circuit board is hidden behind the belt buckle. Everything is thoroughly epoxied/insulated, but there are no saftey mechanisms on this device, making it fairly dangerous. A safety circuit should be incorporated locally at each cell. I have worn this for several months and nothing has gone wrong, but there's always a possibility of something catching fire with that much power around your waist; a fire on something strapped to your waist would be very bad.
If you are wondering, the red connector is simply a direct connection to the battery terminals in case I wanted to power something like a tron-esque suit directly from the batteries, bypassing the boost circuit.
Link for the batteries I used:
NOTE: Don't be fooled for cheap chinese cell phone batteries, most can barely carry a charge. These Japod batteries are an exception and actually have genuine capacity markings, even after months of use.
Conductive Ribbon used:
The charging and boost circuit board:
Information on usb data line voltage and charging for apple products:
NOTE: Most android smartphones just need the data lines bridged (no voltage necessary) to charge at the correct rate.