Now that my project for raspberry pi as surveillance system is active, I also need backup power supply if any power interruptions comes. With just 2 AA size battery size the surveillance system can run up to 1 hour and 30 minutes, just like my earlier test of 4 AA size batteries that lasted for 3-4 hours but my earlier test does not have a usb wifi dongle and a usb webcam controlled by motion program for surveillance. It can be upgraded by adding a parallel of AA size batteries which is much cheaper, safer and easily available source of power for our mini computer.
Well, adafruit's minty boost is hard to find locally but there is an alternative to it created by DFRobot. Our friend circuit-help sells it for Pinoy hobbyist, and it's better than to have nothing, the chip used by adafruit is available in RS Philippines website so if you want to build your own you can build it because it's open source and instructions is also available to their website. Now I can bring my Raspberry Pi in my pocket for 1 hour and 30 minutes for surveillance but only after I found a quality webcam to hide whenever I have a mission.. =)