Guess it is the fast discharge from full to empty which Tecnam found caused the problems. Electric cars do not seem to have it – there are 10 year old models, used every day, which still have over 90% of their capacity. But then they are not run full power through take off and climb.
Looks like hybrid will get there first – but that requires lots of calculations. Toyota Prius, while good for a petrol (gas) car consumption wise, got thumped by diesels…