- Charge times are slower in sub-zero temperatures
- In extreme cold, an EV battery might not charge without pre-heating
- The chemical reaction inside the battery is slowed down
- You can expect a 10-20% decrease in range in sub-zero temperatures depending on how you drive
Will an electric car work in the winter? Yes, although drivers face longer charging times and reduced range when temperatures drop.
Cold temperatures lead to a fall in conductivity, so cold temperatures affect both charging speeds and battery performance.
When you try to charge an electric car with a cold battery, charging speeds are restricted because the electrochemical reactions inside the battery cells are slowed down. In extreme cold, the reactions are nearly at a standstill.
You might get a “Limited Charging” charging message or something similar warning you that charging speeds are restricted due to cold temperatures. Annoyingly, however, some EVs offer no warning, leaving you tearing your hair out over why it won’t charge.
What happens to an electric car in winter?
In winter, three things happen to an electric car:
- Slower charge speeds: Cold temperatures slow down the chemical reactions inside the battery, which can restrict charging speeds. A cold battery won’t charge rapidly until it is up to temperature, which is why pre-heat mode is so important.
- Loss of range overnight: Cold temperatures sap power from the battery when parked. In sub-zero temperatures, a cold battery will lose around 4% charge parked overnight. This is because the ions inside the battery lose charge when the liquid electrolyte thickens in cold temperatures.
- Reduced range: Cold temperatures sap power from the battery in drive, reducing range by 10-20% in sub-zero temperatures. This is because the battery’s thermal system is powered by the battery, and it has to work overtime to manage the battery in cold temperatures. In other words, your car draws more power.
“Starting” a Tesla in -34C weather
Starting an EV in sub-zero temperatures is easy, so long as you can connect your electric car to a power outlet to enter pre-heat mode!
SaskTesla demonstrated this in his YouTube video, “Starting” a Tesla in -34C Cold Canadian Winter. In it, he pre-heats his Tesla with an outside temperature of -34C:
“It took a grand total of four minutes to warm it up,” says SaskTesla, “I’ve got the winter tyres on it, all-wheel drive – this thing is unstoppable in the winter.”
Watch his video below, or click here:
In another video, SaskTesla tests leaving his Tesla unplugged in winter overnight to see how much range it loses. He lost 5% charge overnight, and pre-heating uses another 1.5% (in milder conditions, pre-heating uses around 1.1%).
How cold is too cold for electric cars?
Electric cars can start and drive at temperatures as low as -45C. We know because Tesla tests its cars at a secure facility in Alaska. However, with temperatures this low, you can’t use the battery without heating it.
Why a cold battery won’t charge fast (or at all)
Ions travelling inside the battery travel through a liquid electrolyte. At lower temperatures, the liquid becomes thicker, and in sub-zero temperatures, it can go near-solid.
Because the ions move more slowly in cold temperatures, the electrochemical reaction that charges the ions is slower, resulting in slower charge times.
This process is also why batteries lose charge faster when it’s cold – EVs lose range in winter because the battery is less efficient in cold weather.
In sub-zero temperatures, some EV batteries won’t charge at all without being heated.
The problem of batteries not charging in sub-zero weather is well-known, which is why some electric cars have a pre-heat mode for the battery.
Pre-heating primes the battery for charging by heating the liquid electrolyte, so that the ions can move around freely.
What if I have a 0% battery in sub-zero temperatures?
If you have access to a wall charger, plug it into your electric car and select the pre-heat mode on the charger or your smartphone.
Your EV will draw power from the charger to heat the battery and cabin, and you should be able to start charging within 5 minutes.
You can also pre-heat your electric car using the energy stored in the battery, so you can safely leave your EV parked overnight without a charger.
If you don’t have access to a wall charger to pre-heat the battery, and your battery is at 0%, you can call a breakdown service that offers mobile charging.
Will an electric car work in the winter?
The UK has a relatively mild winter so the chances of your EV’s battery freezing to an unchargeable state is slim to none. At 0°C, your battery should charge fine but you might get a ‘limited charging’ warning on your touchscreen.
When parked in sub-zero weather, the battery will lose up to 2-4% charge overnight just from being parked, because cold saps power. Driving in sub-zero weather will also drain the battery faster, with a range reduction of around 20%.
