When you factor in the drop in temperature, the disconnection between the technical data and the real-life performance becomes even more obvious. Electric vehicles are especially affected, as the Li-Ion batteries are sensitive to cold. This is why most EVs have thermal management systems to keep the battery within an optimum temperature range. But this also takes its toll on the range, as there is no such thing as free energy.
To discover how much range EVs lose in winter, What Car? tested 10 popular models, four of them also being tested in the summer. The temperature during the test was around 37-47 F (3-7 C), so this was not freezing cold. The results were stunning: the four electric cars that were also tested during summer lost between 16% and 29% compared to the summer results. Even those were a far cry from the WLTP claimed range, so you get the picture.
The Porsche Taycan (WLTP rated at 287 miles) saw its real-world range drop from 281 miles in the summer to 224 miles, while the Skoda Enyaq iV (249 miles WLTP) fell from 207 miles to 174 miles. It turns out that having a small battery does not help, as the Fiat 500e (198 miles WLTP) dropped from 140 miles to just 118 miles. Ford Mustang Mach-E (379 miles WLTP) lost 18%, going from 302 miles in the summer to 247 miles in cold conditions.
Besides those four EVs that What Car? tested both in winter and in summer, there were other six models for which there was no summer reference. These were the Tesla Model 3 Long Range and Model Y Long Range, Kia EV6 GT-Line AWD, BMW iX3 M Sport, Audi Q4 e-tron 50 quattro, and MG 5 Long Range. All of them showed a range penalty and, based on the above findings, you can expect around 15-20% fewer miles from an EV in the winter than in summer.
What Car? test also shows how much difference a heat pump can make in the winter. EVs without a heat pump lost an average of 34% of range, while those with a heat pump fell only 25% shy of their claimed range. So maybe configuring your electric vehicle with a heat pump might not be such a bad idea, especially when you live in a region with very cold winters.