Submitted by billtphotoman on 14. Januar 2019
This thread might help some people plan for the worst Wh/mi on road trips by seeing some real world examples of the impact of speed, wind, air temperature and cabin temperature on their energy usage.
I will start with 2 cases for my RWD LR model 3 with 18 inch aeros which I keep at 45 PSI cold.
1) case 1 - the 130 tollway in central Texas on the section where the speed limit is 85 (yes it is): 440 Wh / mi at 85 MPH into about a 10 MPH wind with the air temp about 50 and the cabin heat set to 65 on a sunny day (so, cabin heat impact negligible). On that same road and at that speed I usually get in the 330 Wh / Mi range so wind clearly matters especially at 85 MPH.
2) case 2 - highway near the Texas coast that was pretty much flat. 310 Wh / mi at 55 MPH with about a 20 MPH cross wind with the air temp at about 45 and the cabin heat set to 65.
Case 1 didn't surprise me but case 2 definitely did. I guess cross winds really screw up the aerodynamic wind flow. This was the first time I have seen over 300 Wh / mi at steady state speeds below 75. Usually below 60 MPH I see sub 200 Wh/Mi so this case really surprised me and made me glad I wasn't cutting it close on my battery reserve.
My overall lesson: Wind matters. A lot.