After the recent weeks of extreme cold weather across most of the US, you may have seen stories about EVs losing their charge out in the cold. Or worse, maybe you experienced this yourself! This might seem a little alarming, especially if you’re considering upgrading to an EV and live in a cold region. Thankfully, there are lots of strategies to help manage the effects of cold weather on your EV! Let’s talk about why EVs are affected by cold weather and what you can do to keep them charged up, no matter the temperature.
While hybrid vehicles have been around for a few decades, fully electric vehicles are still pretty new to the market. Recent tax incentives for purchasing EVs combined with a big surge in availability has meant that many of us are buying our first non-combustion car ever. It turns out that there’s a bit of a learning curve in how to use and care for EVs! A lot of common car knowledge and habits are based on combustion engines, and there are some major differences in how the two types of cars function day-to-day.
Before we get into the issues with EVs, it’s worth noting that cold weather negatively impacts all kinds of car engines and batteries. Gasoline fuel economy drops up to 33% in cold weather, and starting a diesel engine in sub-zero temperatures is five times harder than at summer temperatures. Standard lead-acid car batteries struggle with charge and capacity in cold temperatures, and even the common practice of warming your car up by idling in the winter has been shown to damage engines because of excessive friction in cold temperatures. Driving in cold temperatures can be a challenge, regardless of what kind of vehicle you’re in.
While combustion engines have plenty of their own cold-weather quirks, most of us probably don’t think too hard about them because we’re so much more accustomed to combustion engines. Also, for now, filling up the gas tank is still more accessible in a pinch than charging an EV, so reports of batteries draining quickly are more striking than gasoline fuel economy dropping.
There’s no denying it—cold weather causes problems with EV battery life and charging speed. While car companies are working on solutions to mitigate the issue, it’s a situation anyone with an EV should be aware of, especially in colder climates. So what’s going on with cold weather and EVs?
First, let’s talk about why cold weather affects EV batteries generally. Lithium-ion batteries, which for now are the standard battery option in EVs, use an electrochemical reaction to charge and discharge power. This process involves ions moving between the anode and cathode of the battery through an electrolyte fluid. Basically, cold conditions makes the movement of ions sluggish, which can greatly affect the battery life and charging speed. This is the same reason smartphones tend to die faster in cold temperatures!
This causes two main problems with cold weather and EVs. First, the amount of power you can discharge drops once temperatures go below about 40 degrees Fahrenheit. In practice, this means that driving range can quickly drop 10-15%, up to about 40% if using the cabin heater. If you’re not expecting this drop in driving range, this can be a big problem!
The second problem is with charging the battery. The slowed electrochemical reaction in the battery means that recharging takes a lot longer than it would in more temperate conditions. Also, fast charging in sub-zero temperatures can actually cause damage to the battery, so EV software often automatically slows the charge to prevent damage. Again, if you’re not expecting this slowed charging speed, you could find yourself stuck on the charger for much longer than usual, or even unable to charge your car at all.
These battery issues may make driving an EV seem intimidating, but thankfully, there are some strategies for managing the cold, just like there are with combustion engines. Here are a few tips for getting the most out of your battery in below-freezing temperatures!
1) Preheat your battery. A lot of EVs now have software to manage cold batteries by warming the battery up before you start driving or charging, but this uses power. Check into your vehicle’s cold weather settings to see how to preheat the battery while the car is still plugged in, before you drive off into the cold.
2) Don’t let the battery get below 20%. If the battery gets lower than 20% and you’re away from a charger, you may not have enough power to run the battery pre-heat cycle, which will make charging almost impossible. So do your best to keep your EV’s charge above 20% all winter!
3) Plan your charges (and with some cars, put them into the GPS!) In cold weather, it’s important to have a plan for charging to make sure you don’t get stranded. Also, some vehicles have software that will help you plan your battery heating and charging strategy based on your plans for the day. So, for example, if you enter that you’re headed to a supercharging station first thing, your car will know that it needs to preheat the battery (and also that it’s safe to use the energy to do so).
4) When possible, park indoors. Since the ambient temperature of the battery is the main issue with charging, you’ll have much better results if you can park in an area where the temperature stays above freezing.
5) Be mindful of using the cabin heater. Without the heater, you can expect a 10-12% drop in driving range in cold weather, but with the heater running, you may see a 40% decrease in range! Try to heat the cabin while still plugged in, or use the seat warmers instead of the cabin heater to save some precious battery life.
6) Check your tire pressure. Temperature fluctuations can lead to low tire pressure, and under inflated tires require more power to keep the car moving. So keep your tires filled properly to save battery life!
EV manufacturers and scientists are working on solutions to these cold weather problems, from better battery warming systems to new battery technology that doesn’t contain a liquid, temperature-sensitive component. But in the meantime, a little knowledge and attention can keep your EV charged up and on the road no matter the weather.