thank you for your reply. I found these two videos:
with a speed of 75Mph the consumption is 19.9kwh/62,5mliles (62.5miles=100km)
with a speed of 68,75 => 19,2kwh
with a speed of 62,6 => 15,5kwh.
maybe with 68,75mph I can manage to reach my destination (270km=168,75miles).