Battery for 1/8

[Mugenextreme]

Have a question with regards Batteries for a 1/8th buggy. I am currently in the process of converting a Losi Eu from Nitro to Electric. have the conversion kit / speedo and Motor pretty much picked out but i was wondering what kinda/brand batteries are people using. Is a 4 cell the norm if so what sort of mAh are people running and approx what kinda run time should you see?