Try this charger on ebay look for Dimball in community and serch for this charger MUCH MORE (#PT-ADSIC) Slient Charger Platium this is about £66 posted and a very good charger for lipos. I use this one

I use Trakpower 4900mah in b4 and get 2 runs before charging i would get 2 sets to be safe loads of power with brushless