I use this one. Its a Dynamite Life pack 1300 mah and it last 3 quals and a 20 min main. I started a thread a few months ago and was recommended this pack and it works great.
http://www.dynamiterc.com/Products/D...ProdID=DYN1413
I had the reedy 1700 and it works good too but you cant use the flat receiver top. You can use the flat top with the dynamite pack though.