I dont think the battery is related on your problem at all, there is a few things you want to consider checking, first is the steering arm, if you have one of those adjustable steering arm try to compare how far is one arm from the other its probably too far out . second is the steering servo, probably when you assemble it it was'nt center at all which means is that it steer more on one side only.last is the controller you can actually adjust from the controller on which you want the car to turn and how far it will steer. check those, my numbering probably not right but consider checking all of those.