How to Make a pocket USB battery

Change a normal 9v battery into a life saver. If you have ever run out of juice on your phone and could really use a quick charge, then you need a USB battery. Take a look at this instructional video and learn how to create a pocket USB battery. Materials you will need for this process are one 5.1v zener diode, one 330-ohm resistor, a 9v battery connector, a 9v battery, a solder, and soldering iron.