I have been browsing internet for some cheap Arduino power source. I have found some overpriced lithium backpacks... Than i decided to make my own one. It is very cheap thing.
Step 1: Parts and Tools
Step 2: Glue and Connect Switch
At first we must glue switch to battery holder. Than cut and bend red wire. Solder it to one contact on switch and. Take short piece of wire and solder it to other contact on switch.
Step 3: Connect Power Connector
Get the wire going from the switch and solder it to inside of the power connector. Take ground wire and solder it to outside of the power connector.
Step 4: Insulate Switch...
Insulate wires and switch with hot glue.
Step 5: Attach It!
Attach your backpack to arduino with rubber bands and you are done!!!