General Motors is warning some owners of the 2017 Chevrolet Bolt EV that their electric car may suddenly lose power because of faulty battery cells—the first known battery glitch for the automaker’s well-received all-electric car.

“Due to a battery low-voltage condition, the car may incorrectly report remaining range at low states of charge and lose propulsion before the customer expects,” Chris Bonelli, coordinator of global advanced technology communications for GM, said Friday morning.

Bonelli added, “Of the more than 10,000 Bolt EVs sold to date, less than 1 percent have experienced this issue so far.” But a few hundred have shown signs that the battery is at risk, and GM is contacting the owners of these vehicles, he said. 

What Bolt Owners Should Do

Owners contacted by GM should take their Bolt into their dealer. A mechanic will inspect and repair the battery, or change it out. For replacements, owners will get a new, already tested battery that GM knows is operating correctly, Bonelli said.

“We don’t want all owners to think they’re going to have an issue,” he said. “This happens with a very low state of charge. If someone is affected, we’ll contact them soon and get it addressed as soon as possible.”

GM is not aware of any injury or damage reports because of this issue, he said.

If you haven’t received a notice but still have concerns, Consumer Reports recommends paying more attention to the remaining expected range gauge on their cars.  

“Keep your state of battery charge high, even if that means topping it before you normally would,” says Jennifer Stockburger, director at CR’s Auto Test Center.

CR also recently tested the Bolt's range in a head-to-head comparison with Tesla's Model S 75D, under normal driving conditions. The Bolt traveled 250 miles before running out of juice on one full charge. The Model S made it 235 miles in the CR test.

Bonelli said the automaker became aware of the problem from data sent through GM’s OnStar telematics system, which sends vehicle performance information from the car to the automaker.

Consumer Reports owns a 2017 Bolt EV (shown above), and we’ve run just over 4,000 miles on it without a battery incident, according to CR chief mechanic John Ibbotson. And CR has not been notified to date by GM, he adds.

The 2017 Bolt EV is a CR-recommended vehicle in the electric car/hybrid category.

One Driver's Experience

The effect of the sudden power was dramatic for Brad Berman. His Bolt stopped suddenly on a North Berkeley, Calif., road even though readouts indicated that it had dozens of miles of range available.

He said the failure came with little warning. Berman, 54, spoke with Consumer Reports on Friday. He first noted his incident on PluginCars.com.

“There was some kind of warning, a mild beep of some kind, that would indicate that you had a door ajar, but there wasn’t even enough time to figure that out on the dashboard before the steering wheel shuddered,” he said. “It was a dramatic and immediate halting of the car’s movement.”

Berman was on his way home from work as a journalist and video producer, and was less than a mile from his home when the Bolt stopped around 5 p.m. Aug. 8.

“From every indication, the car had juice,” he said. “The only thing is, when I would try to shift—in the middle of a busy road where people whip around very fast—into Drive or Reverse, there was a message saying that it couldn’t be done.

“I tried to reboot the car: power down, power back up, and try again. I did that two to three times, until I realized ‘I’m not moving.’ It’s basically like a panic situation, because you don’t know what’s happening.

“After about 2 minutes, I just put it into Neutral. I let it roll back to where I could basically parallel park. It stopped blocking someone’s driveway, but to move it any more would have placed it into a curve in the road,” Berman said. He gave up and walked home, where he waited 2 hours for a tow truck to pick up his car.

Berman said he remains impressed with the Bolt’s range capability and said he’s a little frustrated by the 13 days it took to get his car back, and what he considered a lack of information from GM about the situation. Still, he said he understands that “it’s premature, because we don’t know what the deal is. The dealer said that they had not experienced this event before.”

It’s rare, but not unheard of, for new electric cars to have issues around battery strength readouts. Nissan issued two service bulletins for its Leaf electric car, for the 2011 and 2012 model years. One bulletin instructed dealers on how to improve the accuracy of the battery capacity level gauge, and the other instructed them on how to help owners whose Leaf wouldn’t start under certain conditions.