This ^Honestly, the whole efficiency thing is overblown unless you do very long range trips regularly
I have a Mini E. It should do a whole 145 miles on a full charge, but that's no fun.
So I do a quick trip to town and put it on charge.
I drive an hour (there & back) to see my daughter and put it on charge.
I nip to my parents and back (75 mins) and put it on charge.
I still haven't used more than 70% in one day.
Also, the one time my wife decided to jump in the Mini was also the one time I forgot to charge it, so sees only 30miles range. But, that would have been enough to do the 7 mile roundtrip 4 times....
Instead of asking this in a Petrol-like,I do at least 2 x trips of 250 miles per month down to see my Dad hence my range anxiety
how many tanks to do the journey? how long to fill to max?
What if you think of it as
How many miles would I need in reserve when I get back to my house?
How long would the extra xxxx miles to charge?
So if you are doing 250 miles with a 220 mile range, and you want a spare 30 miles to avoid anxiety, can you add 50 miles of range in less time than
- it takes to walk to the services loo and back?
- less time than it takes to queue at the coffee shop?