Or Reds' web site http://www.rcbatteryclinic.com

What servos are you flying? If you plan on adding digitals, plan on getting a bigger pack or flying 2 or 3 flights per charge.

I just stuck a 4000 mah Duralite system 8volt li-ion with a 5.1 v regulator on my Raptor with all digitals and I can fly all weekend on one charge. The draw back is they are a bit pricey.