in this instructable, you will learn how to build a phone charger in no-time and almost no tools.
all you need is:
2 X 3V coin battery
old (working) phone charging cable
some kind of tape
first, about the charging cable, you need to cut it after the USB connection which will expose 4 wires. you need to cut the two that are responsible for the data transportation leaving only the black/blue and the red wire. then tape the black wire to the rough side of one battery,
now tape the smooth side of the second battery to the red wire of the cable
Step 3: You Are Done!
now tape the two batteries together, with their empty sides facing each other - rough side to smooth side. and that's it!
version 2.0 coming soon