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December 25, 2021
Paul Gipe

Winter Range Loss (or Not) Chevy Bolt EV in Bakersfield California


Recently I fielded a query from friend seeking comment on a widely circulated article by Recurrent on winter range loss in EVs. The implication of the query was that this somehow implies that EVs are not suitable in the winter. Worse, that if you like to hike and explore the outdoors, you can’t use an EV because of winter range loss. In other words, keep driving that low-mileage Subaru or big SUV if you want to go skiing or hiking in the mountains during the winter.

My reply was curt: Hogwash.

We all make accommodations to what we and our vehicles are capable of. EVs and winter are no different than winter and gassers. We’re just accustomed to a gasser’s weakness in the cold, but not so EVs' range loss.

Few people would venture out into the mountains in winter with a gasser and an old starter battery. You’d be courting danger from a dead battery. I can’t count the number of times I’ve struggled to remember the proper sequence for jump-starting a car in winter or trying to start a gasser in the cold by pouring ethanol into the gas tank in hopes of thawing a frozen gas line. It was a rite of passage for poor students where I grew up.

Is winter range loss in EVs something new? No. We’ve known about this since the dawn of batteries more than a century ago. Anyone who has tried to start a gasoline-powered car in the dead of winter with a lead-acid battery knows this. EVs are no different except that the effect varies from manufacturer to manufacturer depending upon the chemistry used in the lithium-ion battery.

Recurrent is an up-and-coming firm that tracks EV data using crowd-sourced participation. (I give them access to my data.) They’re legit. If anyone bothered to read the article they’d find that Recurrent explains that the range loss is temporary and that drivers can easily compensate for the temporary range loss by more frequent charging and other cold-weather practices.

They provide a chart comparing the range loss for various brands. Teslas’ Model 3 and Model Y are the best in class—as expected—with a range loss of a whopping 1%. Yes, you read that right, 1%. There are more Teslas on the road than all other EVs—combined.  You could be justified in wondering what the fuss is all about.

We drive a Chevy Bolt. It has the most range loss of the dozen cars monitored by Recurrent: 32%. Then again the Bolt costs half that of a Tesla.

There are number of caveats to Recurrent’s analysis. First, they only looked at range loss from 70 °F--or the ideal temperature for a lithium-ion battery—to freezing (32 °F). There are many places in North America where it gets much colder; the upper Midwest for example, or Canada. The second is that Tesla “tightly controls the on-board range estimates the driver sees” and the actual range will be less once the car is driven.

Glen Estill confirms this. He lives 150 miles north of Toronto, Ontario and drives a Model 3 extended range. He’s seen about a 30% range loss when it gets down to 15 °F. However, he notes that the “perceived” range loss is greatest at the start of a trip while the Tesla is bringing the battery up to temperature. Then the range estimate stabilizes.

As Estill notes, this is the “perceived” range loss. Recurrent is only summarizing what the car is reporting as an “estimate” of the range. And range estimates are notoriously unreliable indicator of how far an EV will actually go. Those of us driving non-Tesla EVs call the range estimator a “GOM” for guess-o-meter, reflecting this uncertainty.

Estill’s more concerned about driving in ice and snow than range loss. This is a problem all drivers face in winter, even those in all-wheel-drive vehicles whether powered by gasoline or electricity.

As Recurrent explains, there are several measures to compensate for an EV's winter range loss. More frequent charging is only the most obvious. Leaving the car plugged in when you’re not driving is another. This keeps the battery warm and toasty so it’s ready to go when you need it. You can also reduce the battery consumption for keeping the cabin warm by using seat and steering wheel heaters. Some EVs, such as Teslas, use heat pumps for heating the cabin. Heat pumps are more efficient than resistance heating used in the least expensive cars—like our Bolt.

I've never really noticed any range loss. So I thought I’d pull out my data for the 2017 Bolt that we drove for three years to check.

This is very anecdotal. It’s just one vehicle. And it’s just one vehicle in Bakersfield, California where winters are mild. Our summers are brutal, but winters are very mild in comparison to the upper Midwest or Canada.

And, as noted, range estimates are notoriously unreliable. They greatly depend on the car’s performance during its most recent trip. If you drove all day uphill, your range estimate would be low. If you drove all day downhill, your range estimate would be terrific. Regardless, our driving is a mix of city and highway and we typically do a little better than the EPA rating for the Bolt of 3.9 miles/kWh so our driving may not be representative.

I compared the Bolt’s median range estimates for December, January, and February to those from July, August, and September for the three years we leased the car. I compared winter range to summer range and winter range to the EPA rated range for the 2017 Bolt of 238 miles.

The table explains why I never noticed any range degradation. There was hardly any. It varied from +5% to -6%. (I have no idea why range went up in the first winter we had the car. It’s a mystery.) Better yet, the Bolt’s winter range consistently beat EPA’s estimated range by 5% to 7% for our car in the mild Bakersfield climate. In case that’s not clear, our car repeatedly said we had more range than that advertised when we leased it even after three years and 30,000 miles.

If winter range loss was a serious drawback to EVs we would see resistance to them in cold climates. We haven’t. In October, 90% of new cars sold in Norway were electric.

The whole range loss flap reminds me of episodes back in the early days of wind energy when utilities and fossil fuel companies and their henchman would shout that wind turbines couldn’t work in the cold of Minnesota or North Dakota let alone in the Great White North of Canada so we shouldn’t use them--anywhere. My reply then was the same as today: Hogwash. There are now wind turbines all across the frigid upper Great Plains, in Canada, Antarctica, Sweden, Norway, Finland and elsewhere. We found that wind turbines actually generate more electricity in extreme cold than say in California because the air is so much denser at cold temperatures.

It will be the same with EVs. We’ll learn to accommodate to their idiosyncrasies and look back asking ourselves what the fuss was all about.


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