This is a quick and simple power bank from stuff that most people already have lying around in their house.

Supplies

materials

TV remote
30 cm 12 awg solid copper wire
female USB port
lm7805 voltage regulator
two 18650 Li-ion batteries
22 awg stranded copper wire

You can scavenge the lm7805 out of old electronics. Most scanners have at least one. I scrapped the batteries from an old laptop. Newer drill batteries and e-cigarettes are also common sources.

tools

drill
soldering iron
solder
ruler
razor blade
wire cutters
wire strippers
multi meter
1/16 and 5/64 drill bits
sand paper

Step 1: Cutting, Drilling and Sanding the PCB

Open up the TV remote. Remove the PCB. Cut a piece of PCB 9 cm long by 4 cm wide. Lay all the parts on the PCB and mark were the holes need to be. You can follow the pictures to get a rough idea of were the holes need to be. When you have drilled the holes you need to sand off all the green traces on the bottom of the PCB.

Step 2: Make the Battery Contacts

Take your 12 awg wire and strip all the insulation off of it. You will need about 30 cm. Cut one piece about 6 cm long and bend it into three sides of a square with sides of 2 cm. This is for tieing the positive of one battery to the negative of the other. I bent the ends to make a better contact. Cut two pieces 4cm long and bend them like the pieces in picture five. As an optional step you can add a piece of wire for battery support. When you have all the pieces cut and bent slide them into their respective holes and solder them in place.

Step 3: Wiring the Electronics

Insert the voltage regulator and the USB port and solder them in place. Follow the pictures to wire everything together. If their is anything unclear about the wiring feel free to ask me about it.

Step 4: Testing

When you have everything soldered together, get out your multimeter and test it. If it reads between 4.9 and 5.1 volts, then it should be ready to go.