go to hobbypartz.com go over batteries pick gen ace roar aproved.This is the one im getting they have others but 4000 should be plenty and if u decide to race like a buggy or a corr u have the battery for it and there a good price.Make shure u get a lipo bag to.Also hobbyking.com has a nice 4 battery charger for under 100. dollars when my brother in law comes home i let him post everything for ya i m not good with computers.