We have a 3 throw Subaru Ascent and also the MY LR 7 seat with Geminis. With less than 600 mi on the odometer, we've averaged 316 Wh/mi, with most of the driving being rural roads. It's been extraordinarily hot with temps above 100° on most days, and as high as 113°. So we've had to run the air con constantly when driving the car. We've seen efficiency as bad as 390 Wh/mi.
We normally take multiple trips from our home in Norther California to Vancouver, B.C. It's a 1600 mi roundtrip. In our Subaru with a full load of people, all of our luggage and a rooftop box, we get about 23 mpg on average. That's also with 3PMSF tires on.
Being that we take this trip both in the summer and in the winter, we are going to need to decide which car to take - our Tesla or the Ascent.
Those who've driven this route on I-5 know that speeds are often 75-80 mph. Most people drive 5-10 mph over the limit. And the limit is as high as 70 mph in many areas.
With the cost of supercharging at about $0.46 kWh, so far I've calculated that the running costs to "refuel" the Tesla vs the Ascent comes out to about 9% less in the Tesla. If we charge at home it's about 22%. But of course we wouldn't have that option on the road.