I fly a Valiant with YS170DZ CDI. I use JR3241s on the elevators, JR 8411s for rudder/ailerons and small digital servo for throtlle. Using a TP1800 Lipo with a Digiswitch with regulator, I fly 3-10' flights when the batteries are recharged they show that about 45 to 50% of the power was used.
So, what I do is 3 flights and replace the battery.

Good luck
Rene Grebe
Texas