There’s a common refrain among EV skeptics that cold temperatures will wreck havoc on the car’s range. Engineering Explained’s Jason Fenske has taken his Tesla Model 3 on two 2,000 mile road trips to find out how much impact winter weather will have on it.
The answer is that it does make a difference, but not as much as you might think. Yes, batteries operate most efficiently within a specific temperature band, and heating the cabin (especially in older Teslas) takes a lot of energy. But the results are comparable to ICE-powered cars.
Fenske actually drove his Tesla 2,500 miles in the winter, but is primarily interested in the 2,000-mile section that he also drove in the summer. Whereas in warmer weather he averaged 285-watt hours per mile, in the cold he averaged 338-watt hours per mile.
That’s a difference of a little less than 20% and was reflected in his Tesla’s range estimates dropping from 250 miles to 212 miles. That’s much less than previous studies that have found results of around a 40% drop. Admittedly, this is a single test, but even during the coldest, least efficient part of this drive, Fenske’s Tesla only performed 20% worse than the least efficient part of his summer drive.
Crucially, this lines up pretty well with how much less efficient internal combustion cars are during the winter. According to fueeconomy.gov, gas-powered cars are about 15% less fuel-efficient at 20°F than they would be at 77°F.
Bearing in mind that Fenske was driving at temperatures as low as 0°F and that one of the major purported advantages of the gas engine’s inefficiency is its waste heat, that’s an impressive result.
There’s an interesting Technology Connections video about the dangers of “but sometimes” lines of argumentation that claims inefficient systems sometimes have accidental advantages, which I think applies here. Yes, electric cars sometimes have to provide heat in a way that’s less efficient than gas-powered cars, but only sometimes.
Moreover, even when that happens, they’re still much more efficient overall than internal combustion engined cars. According to Fenske, he used the equivalent of just 20 gallons of gas, averaging 100 MPGe.
For those who are more concerned about charging time than efficiency, Fenske spent the same amount of time charging during both summer and winter. That was, though, helped by his charging strategy. By charging more often, from lower battery levels, he was able to spend less time than he would have otherwise had.
As everyone who’s charged an electronic device, like a cellphone or a laptop, knows, that’s because the fuller a battery gets, the longer it takes to charge. That’s why you see automakers quoting short charging times to 80%, whereas topping them up takes considerably longer. So charging less more frequently actually cuts down on charging time, though it does add some distance while you get on and off the highway.