Can anybody recommend what they think is the best battery set up for the DJI 550? I'm using one Thunder Power 5000 4cell 25c per flight and they are only lasting about 6 minutes. Would I be better going bigger or go smaller and use two in parallel? I'm flying with landing gear, camera gamble, gopro 3 or NEX 5R, fat shark tx and battery,10x5 graupner props.