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Discussion Starter · #1 · (Edited)
Based on information from Everything we know about the Chevy Bolt EV fires and other sources.

Recalls at Time of Fire key:
  • 1 = first fire recall of November 13, 2020 (applies to 2017-2018 and 2019 with Korea-made battery)
    • 1(I) = first fire recall interim remedy software (94% charging limit) installed on car
    • 1(F) = first fire recall final remedy software (additional diagnostics, remove 94% charging limit) installed on car
  • 2 = second fire recall of July 23, 2021 (applies to first fire recall cars; all 2019 cars added August 20, 2021)
  • 2E = extended second fire recall of August 20, 2021 (applies to model year 2020-2022)

Blank cells mean unknown (to the public).

FIre DateLocationModel YearBattery
Origin
Build DateTime to FireMileage to FireRecalls at Time of FireState-of-Charge at Time of FireDeep Discharge HistoryNotes
March 17, 2019Belmont, MA2018KRFebruary 201813 months~5,500None[1][2]GM confirmed. Was charging for about 1:15.
September 20, 2019Kiev, Ukraine2017KROctober 31, 201633 months>99,155None~99%Was first sold in the US and exported some time after reaching 99,155 miles by February 11, 2019. Fully charged, then 10 minute drive home.
June 29, 2020Miami, FL2019KRNovember 7, 201820 months20,972None100%GM confirmed.
July 4, 2020Vienna, VA2019KROctober 2, 201822 months15,095None~95%GM confirmed. Fully charged, driven 12 miles, and parked.
July 25, 2020Maplecrest, NY (?)2017KR34-45 months~25,000None100%
July 30, 2020Temecula, CA2017KRSeptember 201735 months~60,000None100%GM confirmed. Customer noticed substantially reduced range and was told that there was no problem in two dealer visits before the fire.
August 5, 2020Tracy, CA2019KR11-22 monthsNoneGM investigated, inconclusive.
August 25, 2020None[1]GM confirmed as mentioned in recall report, but there is no publicly known information other than the date.
October 6, 2020Port St. Lucie, FL2019KROctober 201824 months~17,000None[2]
October 16, 2020Jacksonville, FL2019KROctober 12, 201824 months~30,000None100%1.5 hours after full charging.
October 21, 2020Monroe, NJ2019KR13-24 monthsNone[2]
November 1, 2020Langenfeld, Germany2017 or 2018KRBefore February 28, 2018 (purchase date)33-49 months~32,000None100%Opel Ampera-e. About 8 hours after being plugged into charging station. Presumably full before the fire.
Before November 18, 2020Delta or Bessemer, AL2019KROctober 2018<=25 monthsNone or 1Date is when registration history indicates that it was reported as an insurance total loss. The only information publicly available is from registration history and salvage auction information.
May 1, 2021Ashburn, VA2019KRNovember 13, 201819 months~18,0001(I)~70%YesCharged from ~15% but unplugged before full. Had interim recall software (94% limit) installed.
July 1, 2021Thetford, VT2019KROctober 29, 201822 months~40,0001(F)100%Yes (~50% of the time)GM confirmed. Charged from ~10% to full. Had final first recall software on June 9, 2021.
July 2, 2021Bound Brook, NJ2019KRFebruary 5, 201929 months1(F)100%YesCharged from ~30 miles (~13%) to full. Had final first recall software on April 29, 2021.
July 25, 2021Chandler, AZ2019KR22-33 months~27,0001(F)[2]Horn honking was heard, a feature of the first fire recall final remedy software.
July 25, 2021Glen Ellyn, IL2019US22-33 monthsNoneGM confirmed. Occurred while driving. Had US-made battery not subject to first fire recall.
August 16, 2021Los Angeles County, CA2020USNovember 19, 20209 months~6,000None100%Commonly discharged to ~30%.14 hours after full charging. Not subject to first fire recall (all model year 2020 had US-made batteries).
August 30, 2021Sacramento, CA2017KR46-57 months~36,0001(F), 234 miles remaining, probably ~14%YesWas parked and not charging at the time. Typically discharged low, charged to about 85%. "After getting recalls done" -- presumably final first recall software.
September 13, 2021Cherokee County, GA201924-35 months2 (unknown whether 1)

[1] Four of the first five GM confirmed fires were known by GM to have occurred at high states-of-charge. Three others of these five were known to be at ~95% to 100% state-of-charge, so at least one of these two cars was known to be at high state-of-charge.
[2] Was charging at the time, not stated whether completed.
 

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Looks like the Bolt is fairly safe during Winter time.

The first fire was on March 17 and was only in Winter 3 days before Spring started. No fires in December and one fire in November (November 1).
 

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Discussion Starter · #3 ·
Looks like the Bolt is fairly safe during Winter time.

The first fire was on March 17 and was only in Winter 3 days before Spring started. No fires in December and one fire in November (November 1).
November 2020 to April / May 2021 was the time period of the interim remedy for the first fire recall (software to limit charging to 94%, or use hilltop reserve or target charge to <= 90%). This probably reduced (but did not eliminate) the fire risk.
 

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I've discharged my car twice to under 20 miles and quite a few times to 30%. Does it mean I have a deep discharge history? I have limited the top charge level to about 75% and try to not go under 40%, but it's hard.
I have to charge overnight and park indoors, otherwise i can't drive it at all.
What to do, what to do?

2020 ~ 20k
 

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I saw another version of this chart and also noticed that no fires were occurring in the deep winter months, even before there was any recall "fix" applied. Since the battery fires seem to be related to thermal runaway, in a simplistic terms it makes sense that warmer summer temperatures could be a factor.

For those of us in cold climates where winter range is an issue, it makes me a little bit more comfortable in pushing a bit pastthe GM recommendations. I really want to make this second Bolt work as there is nothing else currently at the price point that works so well.
 

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Since the battery fires seem to be related to thermal runaway, in a simplistic terms it makes sense that warmer summer temperatures could be a factor.
So would a simple (but temporary) fix to the Bolt fire issue be to apply a software change to the BMS that would chill the battery to cooler temperatures in spring, summer, and fall?
 

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Seems so simplistically but I wonder if it can chill that much. In the winter, my garage temps run about 38 degrees, and my driving temps run about 20 degrees. I dont think the current cooling system could manage that!
 

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So would a simple (but temporary) fix to the Bolt fire issue be to apply a software change to the BMS that would chill the battery to cooler temperatures in spring, summer, and fall?
That would be like putting a pack of matches in the refrigerator and expecting them not to light when you strike them.
 

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So would a simple (but temporary) fix to the Bolt fire issue be to apply a software change to the BMS that would chill the battery to cooler temperatures in spring, summer, and fall?
I was starting to wonder if maybe part of the problem could the contactors in the main Powerlink plug on top of the battery that is directly under the back seat cushions. Probably just me being paranoid but I wonder who manufactured that part of the unit.
 

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I was starting to wonder if maybe part of the problem could the contactors in the main Powerlink plug on top of the battery that is directly under the back seat cushions. Probably just me being paranoid but I wonder who manufactured that part of the unit.
The connector for the fuse under the seat is just like the connector at the front of the pack, and at the front and back of the HPDM, and on the side of the inverter to the motor.

The fuses themselves have failed, and required a recall. But as far as anybody knows, they have never caused a fire. GM wishes the problem was that simple.
 

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So would a simple (but temporary) fix to the Bolt fire issue be to apply a software change to the BMS that would chill the battery to cooler temperatures in spring, summer, and fall?
I think that could help but the effectiveness is a question. I would not doubt that GM has a lot of data on that sort of thing. Lower temperatures should make thermal runaway less likely.
 

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So would a simple (but temporary) fix to the Bolt fire issue be to apply a software change to the BMS that would chill the battery to cooler temperatures in spring, summer, and fall?
The last software update has the battery cooling more aggressively, after charging. This was unnecessary in Bolts with packs which were not defective. Horses, and barn doors come to mind.
 

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I've discharged my car twice to under 20 miles and quite a few times to 30%. Does it mean I have a deep discharge history?
I have no technical expertise to give an opinion, but that's not gonna stop me... 😜

I'd base it more on the percent of charge cycles that went below 30% SOC than the absolute number of them.
 

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I saw another version of this chart and also noticed that no fires were occurring in the deep winter months, even before there was any recall "fix" applied. Since the battery fires seem to be related to thermal runaway, in a simplistic terms it makes sense that warmer summer temperatures could be a factor...
Even though it's called "thermal runaway," it's not really a function of ambient temperature. If this were true, we would expect to see lots of fires in Southern California, Arizona, Florida, etc. Instead, they seem to be concentrated on the East coast.

A more likely explanation is:
1. GM announced the original recall in November 2020, advising owners to limit charge. That might have reduced the incidence of fires that winter.
2. Battery capacity is naturally reduced in very cold temperatures, so that might impact the charging dynamics (ie charging to 100% in the dead of winter may not do the same thing as charging to 100% in other seasons)

I don't see GM trying to actively cool the battery to "dead of winter" temperatures as a solution.

...I'd base it more on the percent of charge cycles that went below 30% SOC than the absolute number of them.
We don't know either way. For @vicenac , it's not about what's been done in the past, it's about what will be done in the future. Try to limit charge between 30-90% moving forward to reduce your risk.
 

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Even though it's called "thermal runaway," it's not really a function of ambient temperature. If this were true, we would expect to see lots of fires in Southern California, Arizona, Florida, etc. Instead, they seem to be concentrated on the East coast.

A more likely explanation is:
1. GM announced the original recall in November 2020, advising owners to limit charge. That might have reduced the incidence of fires that winter.
2. Battery capacity is naturally reduced in very cold temperatures, so that might impact the charging dynamics (ie charging to 100% in the dead of winter may not do the same thing as charging to 100% in other seasons)

I don't see GM trying to actively cool the battery to "dead of winter" temperatures as a solution.


We don't know either way. For @vicenac , it's not about what's been done in the past, it's about what will be done in the future. Try to limit charge between 30-90% moving forward to reduce your risk.

Certainly those must be factors.

Warmer temperatures were my first reaction to the initial surge in fires from June 2020 to November 2020. The return of a surge in the spring of 2021 seemed to support that guess.

With active cooling running, it might not be so much a comparison to the ambient temperature as to what the initial temperature of the cell and case structure was if an event were to occur. A lot of little "fires" can occur without much of an incident. It's common for a little "spark" to flash and just go out. This can also be self healing since the fuel in the immediate area is consumed and will not flash again. For a real fire, the cell needs to get above some high limit long enough to really get going.

I was a bit confused about geographic location too but I think the preponderance of October/November 2018 manufacturing dates may have lead to that. For a long time I thought it was basically a MY 2019 east coast problem.

At any rate, I was thinking that maybe GM/LG had some data on fire likely hood vs charge level vs cell temperature. My thinking has lead to a belief that this may be more of a threshold problem than might be appreciated. In other words, it's more like lighting damp paper than a match. fwiw
 

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At any rate, I was thinking that maybe GM/LG had some data on fire likely hood vs charge level vs cell temperature.
Just last night I charged (in my airconditioned shop) using a departure time for the first time. I literally opened the car door at the exact moment it reached the hill top reserve and the dash light went solid green. I use the OEM EVSE on 240V. Usually my battery is around 77-78F in the morning. I overlaid the temps I saw with the drawing @GJETSON had made. I was surprised that the battery was nearly 90F where the BMS resides. Maybe why there's so many fires that appear to start under the rear seat??? I've seen others speculate as much.
Rectangle Font Parallel Slope Diagram
 

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Just last night I charged (in my airconditioned shop) using a departure time for the first time. I literally opened the car door at the exact moment it reached the hill top reserve and the dash light went solid green. I use the OEM EVSE on 240V. Usually my battery is around 77-78F in the morning. I overlaid the temps I saw with the drawing @GJETSON had made. I was surprised that the battery was nearly 90F where the BMS resides. Maybe why there's so many fires that appear to start under the rear seat??? I've seen others speculate as much.
90 degrees F is barely high enough to trigger the battery conditioning (cooling), and that's not even certain (depends if it's just that one sensor or the pack as a whole).

The fires may be concentrated in the back seat because the main service disconnect (fuse) is located under the back seat, so that is the location where a fire has the easiest physical access to the interior of the vehicle.
 
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