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An exclusive in-depth account of the most recent Chevy Bolt EV fire, plus what you can do to stay safe

40978 Views 233 Replies 58 Participants Last post by  EV Engineering
The recent Chevy Bolt fire on May 1, 2021 occurred just days after the “final fix” for the fire issue was announced. We sat down with the owner to discuss what happened, tell the inside story, and try to find some answers…

Join me with an exclusive that walks you through the morning of that fateful fire, and a brief analysis on the situation, plus things that you can do to keep yourself safe.

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This sounds like there was no neglagence on the part of the owner.
Well, it's unlikely that an owner is going to admit to any negligent behavior in an interview.

The real issue is that the temporary recall was applied. That's something that can be independently verified, and if true, undermines GM's identified root cause and planned solution.
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Thanks for posting, @Telek . This is really why I have zero faith in "software" fixes, that are essentially just smoke and mirrors (pun intended). How does software get ahead of something like this in this situation??
A discussion in another thread mentioned an incident with a Tesla where the software told the driver to stop the vehicle, at 3 different levels of warnings, before the vehicle caught fire. That indicates it's at least possible in some situations for software to detect and protect against fire hazard, but we don't know how effective GM's software will be.

Edit: missing word
We also didn't get the first fire patch. These numbers are typical of our 12/16 build Bolt at 39K miles, sitting a half hour after charging. I would be amazed if GM says there is anything wrong with this pack.

View attachment 34863
When you calculate your battery capacity by charging, noting SoC, driving / discharging, and noting the difference in SoC - do you use Batt % DIC (new PIDs I think it's SoC Disp) or SoC Raw?
I use the DIC SoC. We never get to use the Raw Ah so what would be the point?
I've noticed the DIC SoC is "sticky" - it can sometimes go a couple of minutes of driving before changing values. I was just wondering whether there might be a smoothing algorithm in the DIC SoC, and whether the SoC Raw might be more accurate. I'm not sure, so I'm trying it with both. It doesn't help that we haven't had a consistently warm week up here yet (frost advisory for tomorrow).

...In my opinion, they are rigging the battery test to give themselves the fewest cell replacements possible. The cell voltage delta is lowest between ~30% and ~50%, AND they are changing the delta to pass much worse cells. They are afraid, with testing every Bolt, they would get a tsunami of battery replacements all at once, if they used the original standard. This way they will replace the lowest number possible at first, and only replace the others as they approach failure. Not a noble strategy in my book.
Possible. The counterargument is if they replace too few batteries, then there could be a fire on a vehicle that had the final fix recall applied. If that happens even once, their final fix is out the window and they're forced to replace ALL battery packs, like Hyundai.
That would certainly help but I'm not holding my breath for that to occur. They seemed to think the temp fix was enough to prevent fires while they worked on the perma-fix so saying they know with 100% certainty that the perma-fix would have prevented this latest fire is also a sort of admission that they (at least by now) know that the temp fix was inadequate and could still result in fires. And the other side of the coin, if they were not aware the temp fix wasn't good enough, is an admission that there are still things they don't understand about these fires. It's a lose-lose for them either way.

One of the new recall docs is the dealer service bulletin:

On page 6, after a defect has been diagnosed, there's a warning that makes me wonder if the temporary fix would really prevent a fire:
While waiting for a replacement battery cell module row to arrive, do not charge the vehicle or drive more than a half mile.
Bad news: If having the defect means it's unsafe to drive half a mile or charge at all, then limiting the charge to 90% wouldn't be sufficient to guarantee safety, unless charging to 100% actually causes the defect to manifest in some way.

"Good" news: This could explain the latest fire even if the temporary recall had been installed, and also means it's at least possible that GM's final fix would still be effective. Unlike the temporary fix, the final procedure includes a process to diagnose the defect, replace affected battery modules, and install new diagnostic software that could prevent the car from being driven or charged at all, just like the warning in the service bulletin.

Edit: Part of me feels like GM is having a Pinto moment here. If limiting charge makes it more safe, but doesn't guarantee that a fire can't happen, then it feels like someone has done the risk calculation of the number of fire lawsuits they'd have to pay for vs the cost of taking all affected Bolts off the road immediately (buy back, loaners, whatever).
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Newbie here (our 2021 is only 2 weeks old)....
Apologies if digressing here to something probably covered elsewhere in the forum :
Not to minimize the seriousness , but is my understanding that this risk is eliminated complely as far as anyone knows for Bolts of the 2020 model year and newer correct?

Inasmuch as risk cannot be completely eliminated (ICE vehicles can also catch fire, after all), the Bolts affected by the recall only apply to model years 2017, 2018, and some of 2019 where batteries were manufactured in Nanjing, China Ochang, South Korea. The remainder of 2019 and 2020-21 Bolts have batteries manufactured in Ochang, South Korea the Unitted States.

Look for posts by @cwerdna - he's linked a lot of official information about the recall, including your specific question:

Edit: I confused the Hyundai (China) vs 2017-19 Bolt (S. Korea) manufacturing locations for the 2017-19 Bolt (S. Korea) vs 2019-21 (US) Bolt manufacturing locations. [email protected] for the correction!
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whoa whoa whoa, I was under the impression that the recalled Bolts had batteries from Ochang and subsequent ones unaffected by the recall were made Stateside?
My mistake - I confused the Hyundai (China) vs 2017-19 Bolt (S. Korea) manufacturing locations for the 2017-19 Bolt (S. Korea) vs 2019-21 (US) Bolt manufacturing locations. I've corrected the post. Sorry for the confusion!
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I will admit this news has me much more concerned than I had been....
I posted this comparison in one of the other threads, but given 7 fires in 59,000 recalled vehicles, the risk is somewhere between getting 13 or 14 heads in a row when flipping a coin.

If there are 8 more fires (total of 15), it would be like getting 12 heads in a row.
I'm sure the 7 people whose cars caught fire feel much better knowing that.
And they probably have never even flipped a coin to heads 13 times in a row!!!
I had a stats teacher who said you flip a coin 49 times and it is heads every time, what are the odds that for the 50th?
The class said "50/50."
He said "No way, you better believe there is something wrong with that coin!!!
The point is there is a difference between how policy-makers need to assess risk, and how individuals need to assess risk. You asked a specific question about how worried you should be. The answer is, not much at all. That's not the same thing as saying NHTSA or GM should not be worried - they absolutely should be worried. The difference is that NHTSA and GM are dealing with large numbers (flipping 59,000 coins), while you are dealing with a very small number (flipping 1 coin).

Put another way, if 59,000 people flip a coin 13 times, roughly 7 of them will get all heads. If you flip a coin 13 times, you will almost certainly NOT get all heads. So NHTSA and GM need to act because there are 59,000 affected Bolts out there, and there have been 7 fires. How you choose to act should be based on your personal assessment of the likelihood of getting 13 heads in a row yourself, as an individual.

As I mentioned earlier, people have a difficult time assessing very small probabilities of very large outcomes. The large outcome - either good or bad - distorts our perception of risk. Trying to place the risk in the context of other activities with similar probabilities, like flipping a coin, can help.

And all that being said, I'm still planning to buy a MegaMillions ticket before Tuesday. ;)
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But that isn't how statistics actually works and you aren't counting unknown variables.
If it has happened 7 times so far out of 59,000 vehicles, that doesn't mean the odds are 7 out of 59,000.
I'll freely admit I'm not a statistician. I am planning to buy a lottery ticket, after all. ;)

That being said, I'm looking at this like epidemiology - 7 cases out of 59,000 possible cases. The advantage of epidemiology is that you don't have to define all the pathways and causes - you look at the overall outcome. Having said that, with such a low number of cases, you are correct in that we can't say that the probability is exactly 7 out of 59,000 with a high degree of confidence. When something occurs rarely (like a rare cancer), the confidence interval will be large. However, it's still a rare cancer.

And that isn't the end either. What if it turns out that it is also tied to how people have charged? Then, if your charging pattern matches the triggers, then your odds will be much higher.
I think that's a fair concern, but I don't think your odds will be much higher, because it's still actually dependent on you having the defect combined with having a rare charging behavior.

In the NHTSA recall documents, GM / LG have estimated about 1% of the vehicles have the battery defect. That's roughly 590 Bolts. So right there, you have to assume you got one of the unlucky 590 out of 59,000 Bolts. But we haven't seen 590 fires - we've only seen 7. Let's pretend that a particular charging behavior, in combination with the defect, caused the 7 fires. That means those 7 owners did something that the other 583 owners did not - their charging behavior is something only 1 out of 84 owners do.

So if you want to reduce your risk, charge the way most Bolt owners charge. Don't do weird things that only 1 out of 84 Bolt owners do.

If your charging behavior is rare - like 1 out of 84 rare, AND you have the rare defect, like 1 out of 100 rare, then you may get a fire. But your overall risk - the combination of those factors - is still low, like a rare cancer.

Odds of winning jackpot is tiny and so is odds of fire. I guess one should go buy a lotto ticket. If one were lucky, one would win both. Car fire would be covered by insurance. Lotto win is yours to keep. :)
To be fair, the probability of a Bolt fire is much, much higher than the probability of winning the lottery. If the risk was literally like winning the lottery, there wouldn't be a recall at all.

This is a serious problem that NHTSA and GM absolutely should address, just like the medical community absolutely should address rare cancers. It's just that as an individual, we shouldn't go crazy worrying about our personal risk of a Bolt fire, just like we shouldn't worry about getting a rare cancer. Take some common sense measures - like those recommended by GM and your doctor - and let yourself go to sleep at night.
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If the risk is going below 10% charge, I would like to know that sooner rather than later. I do plan on going on a road trip this summer where my arrival SOC to a DCFC station could be 10% or less.
I would be surprised if that was a pattern among the 6 earlier fires. If it was, GM would have included it in their recommendation and their temporary fix.

One case (the most recent fire) does not make a pattern. However, I'm open to the possibility that GM will update their recommendations as more information comes out about the latest case.

Someone else posted that Electrek indicated there is a pattern among 5 of the fires, of deep cycling followed by lengthy recharging. So you might be on to something.
Kia recall affecting 440,000 vehicles, recommends parking outside due to risk of fire:
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