Portable Power bank for Xperia P

Hey,

Can you suggest a good power bank (for charging portably) for my Xperia P within 2200 Mhz at a budget of 1.5k

I am going on a trip in December, and might need an accidental charge, given the huge power usage of Android phones, and extra camera usage

Suggestions with links to buy online are welcome.........

I was looking at Cooler Master Power Fort 5600 but its way too costly