More Homemade External Power Bank Backup Battery for Smart Phone here:

Homemade Emergency Energy Batteries USB Power with DC-DC step-up module (0.9V ~ 5V) step-up circuit board 5V 600MA USB Charger for MP3/MP4 Phone Power Boost Converter Step Up Module about 2 USD and 1 or 2 cells laptop batteries brand new or take from old battery module broken, very cheap and very esy for home buld, Try it now

<p>This is what this module was made for, nothing more or less!</p><p>Bur you can take of the USB-Jacket, shorten the PCB and use it as a Joule-Thief where ever it is needed...great tiny little thing!</p>