This is a tutorial on how to create your own external battery charger.
Step 1: Things to purchase
- Battery box
- 5v step up voltage regulator
- an extra cable for your cellphone
everything was bought on eBay for less than 10 $ total
Step 2: What voltage do you need?
1- Find the voltage you need by looking at you cell phone wall charger sticker
2- Mine was around 5 V so I bought a 5 V step up regulator
3- Connect the battery box to the voltage regulator using this schema http://www.sparkfun.com/datasheets/Components/LM7805.pdf
red is input , black is ground,
the output is what you want to connect to your cell phone cable.
4- connect the cable (after cutting out the USB part )
Feel free to comment is this tutorial is not clear enough.