RE: Lipos for reciever?
The LiPo's cost a little more than a Nickel-Metal-Hydride
You would need two of these plus a regulator . . . .
LP604374P4HHR 3.7v 1600mAh 74mm L x 43mm W x 6.0mm thick
2.91"L x 1.69"W x 0.236" thick 40 gms (1.41 oz) 16.0 Amps maximum $15.95 ea (From Batteries America)