What you will need.
A small solar panel
And micro USB port
A sodor iron
A battery pack
And something to put everything in.
Step 1: Step One
Wire the the black and red wire to the panel and than solder them down.( you should use the wire strippers to get part of the wire out you want about half an inch to be out)
Step 2: Step 2
Put the batteries in the battery pack and take the wires from the pack and intertwine them with the wires you oust put on. Than solder them both to the micro USB.
Step 3: Step 3
Than you should organize everything than that's it you're done.