top of page

Midwest Freeze: Unease over EV Battery Capacity and Charge Time

A recent stretch of extremely cold weather in the Midwest unnerved many electric vehicle (EV) owners when they discovered that charging their batteries took much longer than expected. EV owners already have concerns about charging cost and time at commercial charging stations; new concerns over charging during an extreme cold snap only makes matters worse.


This article maps out the impact of cold weather on EV battery capacity and charge time. It also looks at the loss of revenue that commercial EV charging station owners are likely to experience when extreme cold weather hits. The solution to both issues is simple: increase the number of Level 3 fast chargers across the country, especially in areas prone to cold snaps. Let’s dive in and find out more.


Batteries in Cold Weather


It’s well known that temperature significantly impacts both the performance and the charging time of batteries. Lead acid batteries found in traditional gasoline powered automobiles are impacted by the cold, as consumers who live in cold climates know well.


Consumers have recently become aware of temperature impacts on lithium-ion batteries used to power electric vehicles. Last week, EV owners in Chicago faced lengthy wait times to charge their batteries in bitter cold temperatures. Low temperatures at Chicago O’Hare International Airport reached -10°F on January 14 and 15, 2024. Chicago Rockford International Airport recorded a high of -3°F on January 14, 2024, setting the record for the coldest high temperature on that day.


Charging EV batteries during this weather took hours longer than usual, while more EV owners waited in lines for access to a charger. Some car batteries were reduced to 0% charge before they could reach a charger and had to be towed. The fiasco had some EV owners questioning the feasibility of electric vehicles in cold climates. The fact that not nearly enough commercial EV charging is available in Chicago, or around the US in general, exacerbated the cold weather charging issue.


Vehicle Battery Capacity & Temperature


The impacts on EV batteries during extreme temperatures are related to chemical reactions that occur in the batteries, and the materials used in batteries. The relationship between the rate of chemical reactions and battery temperature is affected by the conductivities of electrodes and electrolytes that are affected by temperature. Electrodes and electrolytes become sluggish as temperature drops.


Figure 1 shows battery capacity for lead acid batteries found in gas powered vehicles and lithium ion batteries found in EVs as a function of battery temperature. Both types of batteries are rated for performance around 77°F. Once the temperature drops, battery performance decreases, and continues to decrease as temperature drops into the teens and below.


The line graph in figure 1 shows the battery capacity for lead acid batteries and lithium ion  batteries as a function of battery temperature.

Figure 1 shows the battery capacity for lead acid batteries and lithium ion batteries as a function of battery temperature.


If an EV with a 100 KWH battery and a 300 mile range is operated when the outside temperature is 0°F, the range is reduced to 225 miles. Range is not only decreased due to the cold weather, but also because EV drivers are often operating their heaters during extreme cold weather. With the cabin heaters in use, the range of the same EV with a 100 KWH battery will be further reduced to 200 miles.


Vehicle Battery Charge Time & Temperature


Figure 2 shows battery charging times for lead acid batteries and lithium ion batteries as a function of temperature when using a Level 3 fast charger. The optimal temperature for both types of batteries to fully recharge with a one hour charger is 77°F. Of course, actual charging time varies with the type of charger and the model of the charger; not all chargers have the same capability.


The line graph in figure 2 shows battery charging times for lead acid batteries and lithium ion batteries  recharged using a Level 3 charger as a function of temperature.

Figure 2 shows battery charging times for lead acid batteries and lithium ion batteries recharged using a Level 3 charger as a function of temperature.


As you can see in Figure 2, when the outside temperature is 0°F, the time to charge an EV battery to capacity is increased to 84 minutes when using a Level 3, one hour charger. Level 2 EV chargers will recharge EV batteries at a slower rate than shown in the figure during ideal temperatures, and a far slower rate during extreme cold weather.


Increased Charge Time Decreases Commercial Charging Station Revenue


When temperature extremes cause reduced battery range and increased charging times to coincide, EV charging station owners will see a decrease in their revenue. This is due to longer charge times, meaning more time spent at the charger for the same amount of kilowatt hours delivered, and fewer customers being able to access the chargers because of the longer charge times.  


At the ideal charging temperature of 77°F, a 100 KWH, 60 minute charger would deliver 1200 KWH over a 12 hour period by charging one EV per hour. With a billing rate of $0.40 per KWH, the station owner would receive $480. At 0°F, this charger would transfer 850 KWH over a 12 hour period by charging one EV per hour. With a billing rate of $0.40 per KWH, the station owner would receive only $340. This is a $140 decrease in revenue.


This issue is of particular importance in cold climates, like Chicago and across the Midwest. Plus, extreme cold and hot temperatures are likely to continue to occur as climate change progresses. More areas could be seeing extreme temperatures in the coming decade, and must prepare for EV charging even during weather extremes.


Address Temperature Concerns with More Fast Chargers


As electric vehicles continue to be incentivized, with more drivers considering an EV for their next vehicle purchase, charging issues during temperature extremes must be addressed. The key solution is a significant increase in the number of Level 3 charging stations commercially available across the country. This will increase the availability of fast charging stations during peak demand periods, such as during bouts of extreme cold. It will also increase the general availability of fast charging stations.


When the number of commercial fast charging stations across the country has grown exponentially, potential EV owners will be more confident in purchasing an electric vehicle. They will know that charging stations are available at multiple convenient locations, similar to the availability of gas stations. This will boost confidence in EVs as reliable vehicles for everything from the daily commute to road trips, regardless of the weather.


To learn more about how to smoothly integrate Level 3 fast chargers into the existing power grid, check out our EV blog collection. If you are an electric utility that’s interested in assessing your system’s preparedness for widespread EV usage, contact us for a free consultation today.


This article was written in collaboration with Prescient's Lead Editor Alyssa Sleva-Horine.

6 views0 comments
bottom of page