“The reality is we really don’t have fast charging infrastructure today,” said David Slutzky, chairman and founder of Fermata Energy, a startup that builds vehicle-to-grid charging systems. “They almost all step down the charge pretty quickly.”
There are many good reasons why even the slickest public chargers rarely run at maximum capacity. The chemical wizardry of battery power is more complex than pouring liquid into a tank, and both internal and external factors take their toll on charging speed.
For starters, an EV itself can only absorb electrons so quickly. 55 Electric Models Now Available in the UShalf charge above 200 kW and only five can charge at 350 kW. These speeds are further compromised in very hot or very cold conditions. Extreme temperatures can damage a lithium-ion batteryThat’s why car manufacturers program their cars to slow down charging at certain temperatures.
Even trickier, EV charging naturally slows down as the car’s battery nears full capacity, to keep it from overheating. (Smartphones and laptops do the same.) The details of this charging curve, however, are unique to every car. brands are careful about sharing that specific data, even with the people who buy their products. Tesla For example, vehicles have relatively steep charging curves, meaning the ‘fast’ part of the charging process doesn’t take long.
Finally, charging networks themselves limit the flow of electrons. On a hot day, the local grid can be overwhelmed by thirsty air conditioners, or the cords at the plugs can nearly overheat. Many stations distribute power to cars, allowing them to install more cords of the same electricity. In other words, a 200 kW charger becomes a 100 kW charger when someone uses their second cord. (The U.S. Department of Energy classifies plugs rated at 50 kW and above as “fast.”)
“There’s kind of a complicated connection between the vehicle and the charger, so I think there’s definitely an education gap,” said Sara Rafalson, executive director of policy at EVgo.
That gap threatens to hurt electric vehicle adoption in the U.S., where charging speed has become a marketing metric. Automakers like to trumpet how quickly their cars can go from 10% or 20% full to 80%, while public charging stations display the maximum charge speed — not an average or expected — right on the machines. About 17% of public chargers in the U.S. are rated at 100 kW-plus, compared with 10% in the U.K. and 2% in the Netherlands, according to BloombergNEF.
“We still see a lot of disconnect between what the customer expects and what they see on site,” said Anthony Lambkin, vice president of operations at Electrify America, which nearly 1,000 US stations“The good news is we have a lot of new drivers and this is just one of those learning curve things.”
Consumers are slightly less optimistic. A snapshot of 103,000 Tesla charging sessions found average charging speeds of 90 kW — less than half the maximum, according to Recurrent Auto, a startup that tracks battery health. And in a recent JD Power SurveyEV owners scored public charging speeds near the bottom of the 10 categories studied. Brent Gruber, executive director of J.D. Power’s EV practice, said consumers develop false expectations “when you put those (kilowatt) numbers on the charger itself.”
Tax agency executives acknowledge they could do more to inform consumers, especially those new to the market. electric cars. “That’s still a challenge,” Lambkin says. “But there’s a real technical aspect to it that seems to attract people. People get really, really excited when they see that they’re hitting their maximum charging speed.”
The inherent complexity of charging means the speed gap will never close completely, but it should start to narrow in the near future. Charging networks are being built faster and larger stations in the U.S., which will alleviate the need for power dilution across plugs. As of late 2022, each station built by Electrify America is capable of delivering 350 kW, and some of its locations now have 20 charging spots.
Automakers have also recognized that maximum charging speed is a deciding factor for car buyers and are increasing it in future models. “There will be a technology catch-up that will have to compensate for the learning curve,” Lambkin says.
But for now, the best way to deal with the unpredictability is to prepare for it—sometimes stubbornly. Before Jacob Espinoza sets off on a road trip from his home in New Mexico, he runs through a three-part checklist: Enter his destination into a route-planning app; check charging network apps; and check Plugsharea platform for crowdsourced charger reviews.
“If you do those three things, it’s really not that hard to do long trips in an electric car,” says Espinoza, describing his battery-powered road trips on YouTube.
Back in Rock Springs, I paid the price for skipping Espinoza’s steps two and three. After about 15 minutes of 50 kW charging, we cut our losses and drove another 100 miles north to Pinedale, Wyoming, where two cords were spinning in a dusty lot behind Stockman’s Saloon and Steakhouse. The “Border The Days festival was in town, so we walked over to catch a folk concert.
With a maximum charge rate of 120 kW, the Pinedale plug should have been much slower than our 350 kW machine in Rock Springs. But we only had to drive 90 miles and it did it in a few minutes. These were Frontier days indeed.