During the first segment back I reset the trip odometer, efficiency calculator, and average speed calculator in the car while on the freeway and recorded a ~100 mile stretch on flat Central Valley highway at 90-95F, tires underinflated by ~2 PSI (36 PSI cold, 40 PSI hot), the A/C set to automatic mode at 73F target temperature, cruise control set to 76 mph, and apparently calm conditions with little to no wind.
Over that stretch my average speed was calculated at about 74 mph due to rare and temporary mild congestion slowdowns. My average efficiency was 3.4 miles per kWh from the battery or about 300 Wh per mile. That's consistent with a range of around 190-200 miles with 58-59 kWh of available energy.
Very interesting. Thanks for the info.
I did a similar run twice recently in my 2013 Model S P85, with 267 and 287 Wh/mile, AC on, first time with no additional passengers, 2nd time with 3 passengers. My cruise control was set to 78-80 mph most of the trip, but also both hit congestion at the beginning, more so the first time. I wasn't trying to data collect, so there were speeds involved going with the fastest of traffic on I-95 that I won't admit to here. There was enough traffic and surface streets to have an average of 65 mph overall, but the Wh/mi didn't change much from when I looked at it just as I was getting off the highway.
I will try to make a run with an eye towards data collection, but I think the Model S is slightly more efficient at 75+ mph than the Bolt. However, 190+ miles of range with a ~75 mph speed is quite good. That means most drivers in good weather should be able to see 170-180 mile range, driving the way most people do on U.S. highways. That means Supercharging equivalent jumps of 120-140 miles should be comfortable in a variety of conditions. The cadence would be more acceptable if the charge rate was higher.
A Model S driver has to pay attention to avoiding excessive energy use for acceleration and drive in a manner to fully utilize a lower level of regenerative braking to get efficiency comparable to a Bolt off the highway. I think it is very easy to bleed of a lot of energy using the AC induction motor(s) in high torque situations, pushing the average consumption to 300-375 Wh/mile easily when driving surface streets with a lot of stop lights. A Bolt with its newer power electronics and permanent magnet motor does far better there. But on the highway, cruising at 75-80 mph, the Model S has far lower consumption, where I can easily achieve 275 Wh/mi in favorable conditions with AC on, calm weather, and flat elevation.
I do think this highlights why the EPA range calculations are not all that useful for US drivers. They are certainly better than NEDC or JP08... Europeans should look to the EPA results to match their typical driving patterns. For the US, the long distance range is the issue for 200+ mile large battery vehicles. Idaho National Labs AVT did run testing at steady state 70 mph, but with their budget cuts and low visibility, I am afraid we won't see much more good data from them.
