You only need 3 simple things
- A boost converter (This is the cheapest with voltmeter, the same i use)
- A USB Cable
- And is optional, but a estandar DC power plug is usefull
Then connect, adjust the output voltage to 12v and thats all :)
Step 1: Its Simple But Very Usefull
A lot of things works on 12v, and now you have a battery for all of them.
Look a example of how many things you can use it on the right of this image.