First the BEV, now the REx

A couple of weeks ago, we were able to get a 2019 BMW i3s BEV from BMW to conduct our InsideEVs 70mph highway range test and the baby Bimmer finished up with 141 miles of range. Here, we have a brand-new 2020 BMW i3s with the range extender option and repeated the same highway range test.

We were able to secure the vehicle from my friend, Chris Neff, a 3-time i3 owner who had previously leased a 2014 i3 REx and a 2017 i3 REx. Now that he's leased a 2020 i3s REx, he's had an i3 with every battery option that BMW has offered on the vehicle. 

The 2014 through 2016 model year i3s had a 21.6 kWh battery. Then in 2017 BMW upgraded the battery to 33.2 kWh. Two years later in 2019, the i3 received another battery upgrade and now has a 44.2 kWh battery. Rumor has it that the i3 will get another, and final battery upgrade in 2022. If BMW sticks to the same incremental battery increases as they have in the past, the new battery should be roughly 56 kWh, and have an EPA range rating of just under 200 miles (322 km).

The 2020 i3s REx we drove in the range test has an EPA range rating of 126 miles (230 km) per charge. We find that a little odd because the BEV i3s is EPA rated at 153 miles (246 km). Since the REx turns on at just under 6.5% state of charge and is a few hundred pounds heavier than the BEV, we would expect the range to be less, but 27 miles (43 km) less seems a bit much. 

When I bought my 2014 i3 REx, the EPA range rating was 72 miles (116 km) per charge, and the BEV version was 81 miles (130 km). Therefore the BEV i3 had only 12% more rated range than the REx version. 

BMW i3s
Chris & I followed distancing guidelines during the testing and wore masks whenever we were closer than 6 feet from each other.

Then in 2018, I leased an i3s BEV which was EPA range rated at 107 miles (172 km) per charge and the REx version was rated at 97 miles (156 km). In that case, the BEV i3s had 10% more rated range than the i3 REx.

But then in 2019 when BMW increased the battery to 44.2 kWh, the difference in rated range for the two versions became much more pronounced. The BEV i3 now has 24% more rated range (153 mi) than the range-extended version (126 mi), and we're not sure why that is. 

Additionally, our 70mph highway range tests have demonstrated that the real driving range of the two vehicles is indeed closer than the EPA range would indicate, and more in line with the EPA-rated range relationship of previous year's versions. 

The i3s REx finished up with 126 miles (202 km) driven before the range extender turned on, exactly matching the EPA range rating. The BEV i3s we tested achieved a 141-mile (227 km) result giving it 12% more range than the REx i3s in our tests. We're really surprised the i3 REx isn't EPA range rated around 137 miles, (12% less than the BEV version) as it seems that would be more appropriate. 

In any event, the efficiency for the trip ended up at 3.5 miles per kWh (17.7 kWh/100km), slightly worse than the i3 BEV which achieved a 3.6 mi/kWh (17.1 kWh/100km) on the same course. During the video, I repeatedly state the i3 BEV we tested had a 3.4 mi/kWh rating on the highway range test which is incorrect. 

Perhaps early dementia is setting in, but that's what I remembered, and during this test, I was puzzled as to why the i3 REx was achieving a better efficiency rating than the BEV, but of course, it wasn't. It wasn't until I was back at home editing the video recordings that I realized I was incorrect. 

As always, we set the tires to the manufacturer's recommended pressure right before the drive. We drove in the default driving mode, which in the i3's case is "Comfort Mode". The air conditioning was set to 70 degrees and the fan setting was on the lowest setting. There was a very mild 3mph wind from the west and the temperature was in the low 90's (32-34C). 


Once the range extender is running, the i3 can go about 75 (120 km) more miles, but we didn't fully test that out. Our range tests are for the electric range, and usually, we only do pure electric vehicles. However, in the case of the i3 REx, it has such a good electric range it's really more of a BEV than it is a PHEV, and we also wanted to compare the two versions. 

The total EPA range rating for the i3s REx is 200 miles; 126 on battery and 74 more once the range extender turns on. The i3 REx has a 2.4-gallon fuel tank and averages 31 mpg. I recorded the video just above 5 years ago with my 2014 i3 REx, to demonstrate how quickly you can refuel it while on a long drive.

In less than 2 minutes, I pull off the highway, fill up the tank, and return back onto the highway. Granted, the conditions were perfect, but the point of the video was to show how refueling the REx wasn't very inconvenient on long trips when you might need multiple refueling stops. 

Range Test Chart
InsideEVs 70-mph Highway Range Test Chart

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