We have been closely following the Bolt battery issues since the initial recall announcement on November 17, 2020. It impacts thousands of Bolt drivers in the Recurrent community so we will continue to follow this and provide updates. 

August 24 Update:

Following news of a fire in a 2020 Bolt, GM announced a full, voluntary recall of all Bolt EV and EUVs from 2017 to today. This includes vehicles made in the US that were previously exempt from recall announcements. 

The newest recall advises that drivers limit charge above 90% using Hilltop Reserve or Target Charge Level settings, charge more frequently to avoid remaining range dropping below 70 miles, and cautions drivers against parking indoors or unattended vehicle charging. All defective lithium ion modules will be replaced with new ones, and Bolt batteries with replaced modules will essentially reset the clock on their warranties, too. The new modules will have a new 8 year, 100,000 mile warranty. 

The chart below shows how many of Recurrent’s Bolt EV and EUV drivers are charging outside of the recommended charge states over time. Model year 2020 to 2022 Bolt drivers had previously not been covered under the recall, so many had been using the full range of battery capacity. However, after the May 5, 2021 software fix, the percentage of drivers charging above 90% or below 70 remaining miles dropped across model years. 

Overview of Chevy Bolt charging behavior

“This is something that owners of newer Bolts need to start considering as they plug in,” said Scott Case, Recurrent CEO. “Looking at historical data from owners of other model years, we're talking about a lot of people -- potentially 30% of these owners -- who have to change their behavior for a while.”

It is worth noting that we don't know what proportion of people are ignoring the guidelines out of necessity. The Bolt is a popular commuter and some people might actually require more range than the new guidelines allow, especially in these warm summer months. 

August 18 Update:

Now that the news of the July 23 recall has had time to circulate amongst Bolt drivers, we are seeing some significant behavioral changes around charging. The plot below shows the likelihood that drivers in our fleet are charging to various charge percents.

Bolt owners and EV enthusiasts alike have been closely following the Bolt battery issues since the initial recall announcement on November 17, 2020. Impacted batteries are in 2017, 2018, and some 2019 Bolts made in LG Chem’s Ochang, Korea facility.

Bolt charging recall update

The purple shade, representing data from the first recall announcement, shows drivers limiting their max charge via “hilltop reserve” to around 90%, while the pink shows a return to full capacity charging after the software update in May and June. The green shade indicates charging since August 1, showing a clear shift in max charge rate. Drivers in August seem to be keeping their vehicles at a lower maximum charge than they were after the first recall, indicating that they are being extra cautious with their batteries. 

Original Article: August 4, 2021

Since GM has given guidance on where to set vehicle state of charge to minimize risk of fire, we decided to look at the charge levels from 1000 Chevy Bolt drivers subscribed to Recurrent’s battery monitoring to see how this group of highly engaged and attentive owners responded with their charge levels to guidance from GM. 

Chevy Bolt battery charge data from recall notices

This chart shows state of charge observations for Recurrent’s 2017 and 2018 Bolt drivers from October 2020 through today. Vertical lines correspond to recall dates as described below. See below for a detailed view of the recent time period.

Timeline of announcements and response:

  1. November 13 - first recall - In early November, 2020, Chevrolet announced its first Bolt recall. The instructions were to set hilltop reserve, limiting charging capacity to around 90%, and to bring 2017-2019 Bolts to a dealer for diagnostics and possible battery module replacement. In the charging data, you can see a 16% drop off in drivers charging to 100%, as drivers clearly respond to the safety guidance. 
  2. In late April 2021, GM published a product safety recall bulletin, advising drivers to take their Bolts to an EV-certified dealer to get a software update on or after May 5. After this software update is installed at a dealership and the battery diagnostics are run, drivers are advised they can safely go back to charging to 100%. It is assumed that most drivers have this software update by June, but our observations are that only a few return to charging fully.
  3. July 14 - NHTSA issues consumer alert about ongoing battery fires in cars that have had the software fix installed. Owners are asked to park outside until further notice, charging is again restricted to 90% via hilltop reserve or target charge level settings, and drivers are asked to charge their Bolt after every use to prevent charge dropping below 70 remaining miles. On July 23, NHTSA reiterates that all affected Bolts drivers should adjust charging behaviors, and that dealers will replace modules on all 2017, 2018, 2019 Bolts with batteries made in LG Chem’s Ochang, Korea facility.

The data since July 23 doesn’t show much behavior difference in charge levels yet, but there wasn’t an immediate difference in November 2020 either. Slightly fewer observations (5.85% after July 23 vs. 6.45% prior) are above 93%, but we still observe that nearly 19% of Bolts have at least some observations at 100% state of charge since July 23.

The late July guidance was the first time that GM recommended a minimum charge level (70 miles or roughly 30%). Our observations indicate no noticeable behavioral change as a result of this: just 3% of our observations are below 30% state of charge, which is about the same as what we saw before the latest guidance.

“The Bolt owners that we’re seeing data from are probably the most engaged and responsive group out there. They are thinking about their battery health all the time. It’s a little concerning to see nearly 20% of these cars still charging to 100% at times, but it’s understandable given the changing guidance over time,” said Scott Case, Recurrent CEO. 

Used Bolt Sales: Impact on 2017-2019 model year sales

The resale market for used 2017-2019 Chevy Bolts has reacted in some immediate ways in the last week. Used inventory for these model years has increased by 75% in the last 30 days, compared to an overall used EV inventory increase of just 28% over the same period. Meanwhile, the average price for used Chevy Bolts has increased by 2.8% over the last 30 days, which is in line with the overall used EV market figures -- up 2.3% over the same period. 

“It looks like used Bolts are piling up on dealer lots over the last week as buyer uncertainty over the latest recalls is causing people to hesitate. But long-term, a usedChevy Bolt that gets a brand new battery in 2021 is an amazing deal. It’s like the odometer is being reset to zero. ” said Scott Case.