Tesla EVs at Supercharger stations in the winter. New Recurrent study shows cold weather has minimal ... [+] effect on charging times if the battery is at the proper temperature.
Don’t blame electric vehicles, including Teslas. That’s the admonition from EV research site Recurrent after it decided to conduct what it called a quick analysis of charging data from 4,296 Tesla Model 3 vehicles this week in freezing temperatures. Recurrent looked into issues after some Tesla owners in Chicago complained they were stuck in long lines at charging stations in this week’s frigid weather because it took longer than usual to charge cars, while others reported their EVs weren’t holding charges. 3.6 Kw Car Charger
The culprit appeared to be an unfortunate combination of bum chargers, cold batteries and even colder temperatures, according to Andrew Garberson, head of marketing at Recurrent.
Andrew Garberson, head of marketing at Recurrent.
“Failure to preheat the batteries, called preconditioning, certainly played a role in Chicago's sub-zero charging delays,” wrote Garberson in an interview conducted by email. “In an ideal scenario, each driver would arrive with a warm battery so the car could immediately begin fast charging, instead of using the charger to heat the battery for up to 30 minutes. However, it sounds like it was a perfect storm in Chicago, where several chargers were out of order, people arrived from the airport with extremely cold batteries, and a traffic jam formed quickly.”
Recurrent said it based its analysis on Tesla Model 3s because that’s the most common vehicle on Recurrent’s platform, with over 4,000 actively connected. Studying a variety of EV makes and models “can lead to data bias based on vehicle sample size, charging speeds and battery configurations,” the company said in its report.
Recurrent chart showing effect of cold weather on EV fast charging time.
In an earlier, more comprehensive study on how cold temperatures affect an EV’s charging time, Recurrent analyzed more than 200,000 fast charging sessions. It found that charging at zero degrees Fahrenheit adds just nine minutes on average compared to charging in “ideal summer temperatures.”
However, that doesn’t account for preconditioning, a vital function for making sure an EV’s battery is operating at an optimal temperature.
“While most drivers set the charging station as the destination so the vehicle preconditions on the way, some people may forget, or not drive a vehicle that has preconditioning functions,” Garberson said. “All Tesla models do, but some older EV models do not, or do not allow preconditioning while driving.”
Preconditioning is important at both temperature extremes, making sure the battery is cool enough in the summer and warm enough in the winter—especially in the winter.
That’s because chemical and physical reactions in the battery occur more slowly in cold temperatures because low temperatures inhibit chemical reactions and act as resistance that slows down the physical processes, Garberson pointed out, adding, “This reduces the EVs available power. Preheating the battery or keeping it warm while driving would typically alleviate that.”
With that in mind, Recurrent’s quick analysis came to two key conclusions:
• An EV can certainly charge in cold weather.
• Electric cars do not typically charge at a noticeably slower rate in cold conditions, as long as the battery is warmed and ready.
If the battery is not warmed and ready, time at the charging station may actually be wasted.
“If a driver does not (or cannot) precondition the EV battery prior to a charging session, the first 30-45 minutes of your charging session may not add any charge, but instead will be spent increasing the battery’s temperature to prepare for the actual charging,” Recurrent’s study warned.
Quick Charge Electric Car The lesson being for EV drivers: warm your battery or risk spending extra time out in the cold waiting for the battery to recharge.