TFP - thanks for expanding on my post about power. I assumed an average power of around 40 kW from the 85 kW motor (less than 50% power). In practice, I would think the typical Rotax 912 runs at around 60% most of the time so I may have been optimistic.
When I posted, I hadn't seen the battery size. I can't see how 17 kWh could possibly give 1.5 hours from an 85 kW motor. That implies an average power of only 13% or about 11 kW. 11 kW is just about enough to sustain a single seat glider. I can't see it driving a 2 seat trainer round circuits!