As a wild guess: 2 hrs (500 nm at 250 kts) 500 kW (2x250 kW motors) So 500 kW for 2 hours, or 1 MWh. Perhaps battery density is 250 Wh/kg, so around 4000 kg

As a wild guess: 2 hrs (500 nm at 250 kts) 500 kW (2x250 kW motors) So 500 kW for 2 hours, or 1 MWh. Perhaps battery density is 250 Wh/kg, so around 4000 kg for batteries alone. Perhaps serial hybrid would makes more sense?