I use a losi 4s 2200mah 20c Losi lipo (
http://www.carolinasrc.com/Webstore/...idproduct=7762) in my ofna truggy box. When you upgrade the voltage you need to change the wiring and connectors to handle the higher current. I use deans wet noodle wiring and deans connectors, Traxxas would be ok too, depends on what you have. The min c rating is 15c and I wouldnt go any higher than 30c. On the mah I would say the min is 2000 and there really is no max. The losi batteries start both of my cars for a full race day with no prob that includes practice, 3 quals on each car and then in the main. Lipo is so much easier than the old 12v gel and they dont fade like nimh.