Lets set the stage. You just purchased a brand new electric vehicle, you shopped smart and did your research., you took advantage of the tax incentives, and now you are more than happy to zoom off in your brand new electric car. The torque of the electric motor system makes you feel like you’re driving a sports car, and you can’t believe how quiet it is. The best part of it all? You can drive without worrying about negatively impacting the environment. There is, however, a likely reality awaiting you and your new acquisition: cold weather charging.
If you live in places that experience long periods of low temperatures, such as winter in New York where the temperature can dip below 0°C, you have to be concerned about how cold weather will affect your battery.
Your lithium-ion battery effectively powers your car because of chemical reactions taking place within the battery system, whether it is discharging or charging. This works best within a certain ambient temperature range. Generally between 60 and 80 degrees Fahrenheit. As it gets colder and the temperature drops, the chemical reactions take place at a slower rate, making the process less efficient.
Studies and anecdotal evidence show that in colder climates, electric vehicles can lose up to half of their range, depending on how cold it gets. The charging times are also affected, and the type of charger used to recharge your vehicle plays a large role in this equation.
If it is any consolation, gas-powered vehicles also suffer during the winter. They get about 17% less efficient.
There are three different types of EV chargers. Level 1, which uses 120 volt power sources and can take an entire day to charge the battery fully. It is the least complicated of all charging options as it works with a standard home outlet. Level 2 chargers utilize 240 volt power sources and can charge the battery of an electric vehicle to 100% in about half the time a Level 1 charger can. Lastly, there are level 3 chargers. These utilize 480 volt power sources and can give electric vehicles with smaller sized battery packs (20-60 kWh) an 80% charge in less than 30 minutes.
DCFCs like CHAdeMo and Tesla’s proprietary Superchargers are classed as level 3. They typically can provide up to 150 kW of power to your car compared to the 1.4 kW a level 1 charger provides and the 7.2 kW a level 2 charger provides.
All of them are affected by cold weather, but to varying degrees. Simply put, colder weather decreases the efficiency of the system. Here is Brookes Shean, Central Canada’s general manager for the Flo public charging network, explaining the difference in charging levels:
“There are three levels for charging,” he explained. “There’s Level 1, which is your trickle-charge, standard wall outlet, which you’re using now and takes basically all weekend to charge. There’s Level 2, which is a 40-amp breaker, 7.2 kW per hour, and it’s giving that Chevy Bolt about 30 km of driving range per hour that it’s connected. And then there’s DC fast charging, the fast, fast thing, which is bypassing the brain of the battery and going right into the battery to deliver all of that charge.”
The author of the article tested Brookes’ claim, he plugged in a Chevy Bolt, in the middle of a polar vortex, on a level 1 charger for 24 hours and had only 50 km to show for the effort.
What advantage do levels 2 and 3 have over level 1? Apart from taking significantly lesser time to charge during winter, levels 2 and 3 have the ability to do what is called preconditioning. Since lithium-ion batteries work best when warm, you can actually make them more efficient by warming them up before using them. Tesla uses the same trick to make their cars charge faster at their Supercharger stations. The car detects when you approach the station and starts to warm up the battery, using power from the same battery.
Preconditioning also works in the reverse. If you start your trip on a warmed battery, you can get 10-15% more range. Some models allow you to start it through a mobile app. Preconditioning however is best done without taking power from the battery so that you can leave home on a full charge, which means it should take place in tandem with the battery getting a charge.
This is where level 1 falls short. It simply can’t supply enough power to charge and precondition the battery at the same time. You are better served by a level 2 or 3 charger because they can keep your battery charging and still warm it up.
If you have to drive around during the winter, you should certainly install a level 2 charger in your home, or at least make a mental note of where you can make use of level 2 and level 3 chargers in public for quick and more efficient charging.