It's the i3s' turn out on the highway.

The BMW i3 gets the honors of being the latest EV to go through the paces of the InsideEVs 70mph highway range test. BMW of North America was kind enough to arrange for us to have a short term loan of a practically-new 2019 i3s. 

Even though the i3s was a 2019 model year, the vehicle had less than 600 miles on it. There weren't any 2020 i3 BEVs available, so we accepted the loan of the 2019 model. There aren't any changes in the battery or powertrain for the i3 between 2019 and 2020 models, therefore, we would expect the results to be the same if we did have a 2020 model.  

As always, we try to control the variables in the tests as much as possible. The tires are always set before the drive to the manufacturer's recommended pressure. In this case, BMW recommends 39psi for the front tires, and 44psi for the rear tires, which are wider. 

The temperature was 87 F (30 C) degrees at the start and a steamy 95 degrees F (35 C) when we finished up. The air conditioning was on and set to 70 degrees the entire drive, the fan speed was 1, which is the lowest setting. The wind was a mild, 4-5 mph and we drove in the default drive mode; Comfort.

BMW i3s range test
BMW i3s charging up before the range test

The EPA range rating for the 2019 and 2020 BEV i3s is 153 miles. It's interesting because in 2018, BMW listed the i3s as having less range than the regular i3. The 2018 BEV i3 had an EPA rated range of 114 miles and the i3s range rating was 7 miles shorter, at 107 miles.   

But then in 2019, when BMW introduced the new larger battery pack with 44.2 kWh, they reported the i3 BEV and the i3s BEV as having the same EPA-rated range of 153 miles. Since the i3s has wider tires and more power than the regular i3, we'd expect the range to be slightly less, as was the case in 2018. 

BMW i3s range test
BMW i3s range test yielded 139.5 miles with 1% SOC remaining

We were able to drive the i3s 139.5 miles and still had 1% state of charge when we finished the test. Therefore, we believe it's fair to add another 1.5 miles and call this one at 141 miles. The average efficiency was 3.6 mi/kWh (17.2 kWh/100 km) which adds up since the i3's usable battery capacity is about 39.2 kWh (39.2 x 3.6 = 141).

Having previously owned two i3's (a 2014 i3 REx and a 2018 i3s BEV), I was expecting to finish up with a little better consumption rate of 3.7 mi/kWh and get closer to 150 miles, but it wasn't to be. However, I never did a constant 70mph range test from 100% to 0 with my cars, and it's different doing that than driving 40 or 50 miles at a set speed.

You really have to go from 100% down to zero, or very close to zero to really get the full average consumption rating. I've noticed on many of my highway range tests that the vehicle has a lower consumption rating for the first half of the drive but then ticks up one or two tenths during the second half of the drive. 

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About our highway range tests:

We always like to mention that these range tests aren't perfect. There are variables out of our control like wind, traffic, topography, and weather. However, we do our best to control what we can. We do these 70mph range tests to provide another data point for potential customers that are looking for as much information on the driving range as they can get. Check out our previous 70mph highway range tests for the vehicles listed below:

Were the results about what you'd expect? We'd also like to know what the readers think of our 70mph range tests. Is there an EV you'd like to see us range test next? Let us know in the comment section below. 

Source: Tom Moloughney