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I was surprised that the battery was nearly 90F where the BMS resides.

Yup. That is always the case when charging. Module 6 is the hottest, followed by module 5. They are up under the seat with the BMS, and the fuse. However, I don't think it has anything to do with the smoke usually coming from under the seat. That is the only opening in the battery cover into the car. It is at the highest point, and certainly the plastic fuse holder melts pretty quickly. If you were going to make a chimney into the cabin, this is how you would design it.
 

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90 degrees F is barely high enough to trigger the battery conditioning (cooling)
I've noticed that the temperature cooling is determined from the average temperature. The average temperature PID was 27C (80.6F). But if I manually average the six transducers, it is 82.1F (27.8C). So definitely the battery cooling wouldn't be triggered by the one reading 89.6F. Wonder if the behavior has been modified with the recall software?
 

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The average temperature PID was 27C (80.6F). But if I manually average the six transducers, it is 82.1F (27.8C).

Yup. I checked that average PID against averaging the others many times, and decided it didn't make any sense. I dumped it since it doesn't tell me anything real.
 

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Yup. I checked that average PID against averaging the others many times, and decided it didn't make any sense. I dumped it since it doesn't tell me anything real.
I've kept the average battery temperature PID because it appears to be what the car uses to control the battery conditioning. Watch the PID and one can see the conditioning turn on or off depending on the value and the preprogrammed setpoints.
 

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I've seen others speculate as much.
I could speculate that leaving a pack of matches in my garage, that gets up to 125 F, could cause the pack of matches to spontaneously combust. Speculating on nonsense is... nonsense. High temperatures is not the cause of electrical/chemical reactions within a cell, leading to a chemical fire. That is not speculation.
 

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To be statistically correct. The cars that did catch fire could be all that can ever catch fire. Until the modules are broken down and tested there will be no way to know the correct. Hopefully the answer will not be secret. Would be nice to know that only 20 or so failures in the bunch. Would stink if they find ever car had an issue.

Never good etiquette to have a bolt fire after November.
 

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It is strange to me that all of these fires have occurred seemingly all at once, spanning model years, despite some of the cars being very new and others being over 2-3 years old. Is there something environmental that is increasing the risk? Maybe the current Bolt owners are less careful about babying their batteries than the earlier adopters? Maybe "just drive, charge, and don't worry" isn't the best advice?

It just strikes me, and I'm throwing out a hypothesis.
 

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It is strange to me that all of these fires have occurred seemingly all at once, spanning model years, despite some of the cars being very new and others being over 2-3 years old. Is there something environmental that is increasing the risk? Maybe the current Bolt owners are less careful about babying their batteries than the earlier adopters? Maybe "just drive, charge, and don't worry" isn't the best advice?

It just strikes me, and I'm throwing out a hypothesis.
The fires have been spread out over a 30 months span, so I am not sure calling it "all at once" is fair. Based on the limited information we have right now, it seems like the early production 2019s are the highest risk, and by far. However, the newer vehicles could have higher risk, and we wouldn't know yet because there hasn't been enough time for the defects to create a fire.

I guess the bottom line is that we don't have enough information to make any real educated conclusion on that. Even the most well connected, knowledgeable among us (which does NOT describe me) are speculating.
 

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It is strange to me that all of these fires have occurred seemingly all at once, spanning model years, despite some of the cars being very new and others being over 2-3 years old. Is there something environmental that is increasing the risk? Maybe the current Bolt owners are less careful about babying their batteries than the earlier adopters? Maybe "just drive, charge, and don't worry" isn't the best advice?

It just strikes me, and I'm throwing out a hypothesis.
My hypothesis is that the incidence of defects is very rare, except for a particular production run (2019 models with batteries made in Korea).

If we exclude all model year 2019 battery fires, the incidence of fires seems to be sporadic:
March 2019
September 2019
July 2020 (2)
November 2020
August 2021 (2)

That doesn't seem to show much of a pattern.

Now, looking at just model year 2019 battery fires:
June 2020
July 2020
August 2020
October 2020 (3)
November 2020
May 2021
July 2021 (4)
September 2021

There seems to be a run on fires in the summer / fall of 2020, then GM announced the recall in November 2020 and advised owners to limit their target charge level. Then the software-based "final remedy" was implemented in April 2021 and the target charge level was restored to 100%, and we started seeing fires again. GM announced the second recall in July and once again advised limiting target charge level.

So I think it's the model year 2019 Bolts that are driving most of the fires (60% of known fires for less than 10% of all Bolts), and the perception of a rash of fires over the past year.

Absent those model year 2019 fires, we would still have a problem and be legitimately concerned, but I think the perception of the issue would be very different.
 

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My hypothesis is that the incidence of defects is very rare, except for a particular production run (2019 models with batteries made in Korea).

If we exclude all model year 2019 battery fires, the incidence of fires seems to be sporadic:
March 2019
September 2019
July 2020 (2)
November 2020
August 2021 (2)

That doesn't seem to show much of a pattern.

Now, looking at just model year 2019 battery fires:
June 2020
July 2020
August 2020
October 2020 (3)
November 2020
May 2021
July 2021 (4)
September 2021

There seems to be a run on fires in the summer / fall of 2020, then GM announced the recall in November 2020 and advised owners to limit their target charge level. Then the software-based "final remedy" was implemented in April 2021 and the target charge level was restored to 100%, and we started seeing fires again. GM announced the second recall in July and once again advised limiting target charge level.

So I think it's the model year 2019 Bolts that are driving most of the fires (60% of known fires for less than 10% of all Bolts), and the perception of a rash of fires over the past year.

Absent those model year 2019 fires, we would still have a problem and be legitimately concerned, but I think the perception of the issue would be very different.
Yes, and if the 2019 fires are mostly from October and November 2018 production, I think it is much less than 10% of the total.

I wish I knew what was different about those. I'm still a bit leery that my August 2018 build is not actually part of this group. But, I did not get the "critical battery swap letter" so I will assume they are correct. I really hope they are doing something to get those high failure dates off the road quickly now that battery swaps don't seem to be an option right now.
 

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I wish I knew what was different about those.
My bet, is they were changing the chemistry to increase the nickel content. Guessing the rate of flaws hadn't increased, but the chemistry change made those batteries more sensitive to the flaws.
 

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You mean decrease nickel??

Hopefully we will start to get some information from LG and GM soon.

Guess we could put some Edison batteries in, They last 100 years.
 

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Just curious but we purchased our 2020 Bolt one month before the pandemic. As we are working from home since March 2020, the car has been driven about 3,000 miles. The table seems to indicate that the vehicle (at least so far) has had to have several charging cycles before the battery runaway excursion. Wondering if there is some connection between the fires and number of charges. One of the issues is that the data set is very limited so drawing any logical conclusions is not really possible. Also recently saw that the Moss Landing electric battery storage site had a runaway with their LG batteries - connection with Bolt fires?

Regardless we are extremely disappointed with GM - if the Bolts are so bad that you are requested to park them 50 feet from your home then GM should take all of them back and refund the purchase price or provide the opportunity to buy another GM ev for their cost price as a good will gesture for the pain and inconvenience. When I do return to my office, there is a sign in the parking garage next to my office building that Bolts are not allowed to enter. So I’ll have to park about two city blocks away. This entire debacle pulls a humongous vacuum!
 

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My driving habits just changed to where I will be charging at DC fast chargers again. I notice that the table in this post does not indicate what type of charger was in use. Yet all the fire photos I've seen are of home fires. So L1 or L2. Have any fires occurred during or after fast charging??
 

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I don't think so, but remember that fast charging is a very small percentage of overall charging. There's no way of knowing if it really matters or not.
Not sure if you mean a small percent of the fast charging session, since the charge tapers off as the battery gets full... of if you mean fast charging as a percent of all charging sessions of the car, which presumably is at home. I assume you mean the latter. Still, that must be some kind of clue if no fires have broken out for cars that must be fast charged fairly often. Fast charging, just because of the much greater current flowing and heat created, would have you thinking that it would greatly exacerbate an underlining condition that is causing thermal runaway. It must mean something that it does not seem to.

Unrelated, I was pondering why running the car low on charge does seem to exacerbate the condition. Although a differing chemistry, I was thinking about the LFP cells on my solar system. With such a system you need to either TOP BALANCE or BOTTOM BALANCE the pack, to keep cell voltages equal. I suspect it is the same with most all Lithium ion chemistries. If you top balance, when cell voltages get low you get significant divergence in voltage from cell to cell. If the BMS does not balance those cells properly before full charge is reached then you can have some cells greatly exceeding their safe max voltage, while pack voltage will appear near normal. This condition can cause a fire. I have no where to really go with this notion, except I wonder if anyone has captured cell telemetry from a Bolt pack before it ignites. You would need a more granular reading than the 10ths of a volt reading that the Torque PIDs throw, because voltage is a poor indicator of SOC. To even have a chance of reading SOC via voltage you need to display two or three digits to the right of the decimal point. But again, this is my LFP knowledge talking.
 
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