On Monday, December 28, 2015 at 7:38:01 AM UTC-6, wrote:
The bigger issue is the mass of non lifting items. With a low mass glider this becomes a big deal. Batteries in the fuselage increase this mass, leading to need for heavier structure, primarily the spar, this making the whole glider heavier. Move the mass to the wing, somewhat outboard is better, and this problem is avoided.
Bigger motor buys takeoff margin, then throttle back to lower consumption for balance of the climb. Larger battery not really needed.
UH

On both counts, exactly UH ! EY