These are the lipos I'm running in my HBFP v2.
http://cgi.ebay.com/2x-900mAh-11-1V-...item2a03a0185a
With them I get 10-12 minute flight times. They work awsome and they fit nice and snug in the frame. There nothing like the stock lipos. The Esky is thin and long, these are short and fat, but a great fit.