How much range will someone loose to do that if they cannot plug in at home?
I'm sure it depends on a lot of factors, but I think I set a personal record for Wh/mi last night with my 2020 M3 SR+ (no heat pump).
I preconditioned while plugged in but mistakenly just turned on climate instead of using the "Defrost car" option. I was able to get into the car but the driver's window didn't drop, so I couldn't close the door from inside. I then ran the defrost for a few minutes off of the battery, because I had already unplugged.
I then drove .8 miles to my destination with my wife in the back seat as the front passenger door was still stuck but the left rear was working. The right mirror was also stuck in the folded position. When I arrived, I kept defrost on for a while until 3 of the 4 windows were freed up. Less than 2 hours later, I defrosted the car again for a few minutes, then drove .8 miles home. The outside handle of the front passenger door was still frozen but I was able to open it from the inside since the window had come unstuck. The right mirror was still stuck in the folded position.
The car had charged to 80% the prior night. I left home at 76% (4% burned on defrost while unplugged before leaving home), had 72% when I turned the car off at the destination (about 4% burned on defrost while there). I arrived back home at 66% (about 8% burned defrosting and driving home). So this 1.6 mile trip used 14% of the battery on my SR+. Teslamate recorded that I used 8.5 kWh to add 7.4 kWh to the battery. That's about 5 kWh per mile! That doesn't include the preconditioning that I did while plugged in before getting into the car.
In warm weather this trip often uses so little charge that the car leaves at 80% and returns home still reporting 80%
Lessons learned (which I'll promptly forget):
- When the weather is going from wet to freezing, after it gets below 41°F go out to the car and unfold mirrors, then open and close a door so the windows will drop to their 'freezing weather' position.
- Use the defrost button instead of the regular 'climate on' when trying to unfreeze the car
- Start the defrost cycle early. 5 or 10 minutes isn't going to unfreeze door handles.
- Buy a house with a garage
This is the battery level graph for this <2 mile round trip: