J Martindale,

The 2 cell LiFe batteries can be purchased from the same place you got your receiver. You will also need a matching charger. I, and many of our club, have been using those for some time now. We use 700 mAh for Club 40 racing. I use 1600 mAh for Buddy-boxing. Note: Your transmitter sold with a 600 mAh NiCd.

Ken