What batteries are best for rc car?

i recently purchased the call of duty black ops Prestige edition with the rc xd surveillance car with camera. for the past couple of days since i got it ive been putting new batteries in the car itself but i can never get a full read out from the display on the lcd screen where it shows the remaining battery power in the car, the remote control takes 6 batteries and the car also takes 6 batteries, the remote control is fine that showed 4 full bars for its batteries only today for the first time it went down to 3 bars, when i put in new batteries in the car itself i can never get anymore than 2 and half or 3 bars on the read out. it takes AA batteries, i tried normal energizer batteries and energizer rechargeable batteries, same thing. the energizer rechargeable batteries im using are the ACCU recharge 2450mAh.