A chief concern about electric vehicles (EVs)—right up there with range anxiety and cost—is cold weather. We know the cold takes a toll on EV battery life, but why? Let’s look at what happens to an EV’s battery in cold weather, and the steps you can take to mitigate adverse effects.

How Does Cold Weather Impact EV Battery Life?
When the temperature gets low enough, the electrolyte fluid inside an EV’s lithium-ion battery pack becomes more viscous, which slows down the chemical reactions responsible for the transfer of electrons. That impacts not only the range an EV can get on a charge, but also how quickly it can recharge.

Anna Stefanopoulou, director of the University of Michigan’s Energy Institute says in an article for Wired that “batteries are like humans,” meaning they don’t operate well outside of a certain temperature range. For an EV’s battery, that range is between 40 and 115 degrees Fahrenheit. Anything above or below that will cause problems.

To help maintain a good operating temperature, modern EVs are built with battery heating and cooling systems. But those systems take energy to heat the battery since unlike a gas-powered engine an electric motor doesn’t generate its own heat. Heating the car’s cabin, running the defroster, and running the onboard computer systems also require power, sapping the battery more quickly than in warmer weather.

Lithium-ion batteries take longer to charge when they’re cold, and regenerative braking features don’t work as well either. Taken together, the adverse effect of cold weather can reduce EV battery capacity by as much as 41%.

Though all EVs lose some capacity in cold weather, not all of them handle winter the same way. Used EV battery report company Recurrent conducted a study in 2021 comparing cold weather charge loss in thousands of EVs and found some hold up better than others.

In the next few years, we could see EV lithium-ion batteries that have no liquid inside them, largely mitigating the charge losses that come with colder weather. Until that technology becomes widely available, though, EV drivers need to find workarounds.

How to Help Protect EV Batteries From the Cold
There are several ways to help an EV’s battery last longer in the cold, or at least to minimize the amount of charge lost. To start, don’t let the battery get below 20% charge, even if you’re near a charging station. The car’s systems have to warm up the battery before charging can begin, and the battery has to have enough power left for those systems to run. You’ll also need enough power to run the cabin heater, especially in extremely cold weather.

If you’re able, park the vehicle in a heated or enclosed garage to help keep it at a stable temperature. Parking the vehicle in the sun can also get you a little heat. If possible, park in a public garage with an outlet you can connect to while at work or otherwise away from home. Doing so will let the car draw power from the grid to run the battery warming systems instead of the battery itself.

Read more: How Does Cold Weather Affect Electric Car Battery Life?