I've been surprised and delighted by how efficiently my new 2013 Tesla Model S has been running at higher speeds.
Tesla Motors [NSDQ:TSLA] hammers home the message that high speeds can drastically reduce the range of any Model S.
It cautions that its original range figure of 230 miles for my 60-kWh car is based on a steady 55-mph speed, on level ground, and that higher speeds can significantly reduce this number.
(The official EPA range, based on a variety of speeds and conditions, is 208 miles.)
But who drives 55 mph? On multilane highways, certainly not me.
According to a range-vs-speed graph on the Tesla website, range of the 85-kWh Model S at a steady 55 mph is about 310 miles.
At a steady 70 mph, the graph shows a range of 240 miles--a reduction of 23 percent.
If we apply the same 23-percent range reduction to my 60-kWh car, it works out to a range of 178 miles at 70 mph.
Cool temperatures eat away at range as well. According to the range calculator at my local Tesla store, range declines by about 10 percent at 40 degrees. Now we're down to 160 miles.
Knock off a few more miles for hills, and we're looking at a projected real-world range--my real world at this time of year, at least--of maybe 150 miles.
But I actually did much better than that on a trip to New York City last week, under just those conditions.
No hypermiling here; I drove 65-75 mph over moderately hilly terrain, with the outside temperature at 40 degrees and the climate control on a comfortable setting (no shivering, either).
The 117.5-mile round trip consumed 39.2 kWh of juice, about two-thirds of the battery capacity. Average power consumption was 334 watt-hours per mile. That's almost exactly 3 miles per kWh.
Extrapolate those numbers out to the full battery capacity of 60 kWh, and we get a max range of 180 miles. That's a lot better than the 150 or so predicted by the graphs and calculators.
It's a nice little bonus that makes up for a couple of days of "vampire" electrical power usage while the car is parked in my driveway
David Noland is a Tesla Model S owner and freelance writer who lives north of New York City.