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I've tried contacting GM. It's pointless at this time. As you stated above, the lines are overwhelmed and GM is not responding to my attempts to contact them. Neither is the dealer.
Well, each person has their own level of what's worthwhile and what's not. Depending on how valuable it is to you, it may be worth persisting. GM has apparently established a partnership with Hertz for a national rental program for this recall, so you might try asking for a rental instead of a loaner. Again, the EV Concierge number appears to be the way to work the process, rather than individual dealers.
 

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I would just point out that in the May 2021 example, the owner didn't say that he discharged once or a few times to 15%. Rather, it was "typically charged when it got down to 30 miles of range" (roughly equivalent to 12-13% - source). In fact, it was Electrek's investigation (Sean Graham) of this particular fire that led to the tidbit from GM that many of the known fires had a pattern of deep discharge, full recharge, or both.

That's the thing about patterns. It's not a hard and fast rule - it's a pattern that seems to reveal something about the underlying risk. It's also fair to say that the pattern only matters in the presence of the defects. An owner might regularly discharge deeply and recharge to full and never experience a fire - because that Bolt doesn't have a defective battery.
This article touches on swelling that occurs in Li-Ion batteries: Why Do Lithium-Ion Batteries Swell?

So, BMS updates might be in order. When SOC is low, limit it to a lower current (trickle charge) until SOC reaches 30-40%, then ramp it up till SOC approaches 85-90% and start ramping it down. For those who ask, is it better to use L1, this sure seems to be true, at least when SOC is deeply depleted. It might also be true that aggressive regen at low SOC may be a problem, so BMS updates to reduce regen at low SOC, like at high SOC might be in order.

The point is, in the presence of cells with defects, deep discharges are stressful, as is topping it off. Over time, regularly deep cycling the pack may contribute to failures caused by manufacturing defects. In other words, you are exposing the defects to a greater frequency of stressful conditions. That is not to say never go into the extreme zones, but minimize doing so. Theoretically, the risk is lower if there are no defects in the cells, but the defect rate is still uncertain, so it seems wise to follow the spirit of the advice.

So the advice is not to never charge to 100%, or run the pack below 30%, but to limit these extremes "out of an abundance of caution". Further, moving the car from your garage has no effect on the fire risk, only on the severity of the event in terms of other property that might be damaged by conflagration.
 

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How many people to date have NEVER taken their Bolt below 30%? And how many have NEVER charged to 100%? If those charges increase the likelihood of a fire, then everyone with a Bolt has already done it. I have 98K miles on mine and have charged to 100% many times, and have been down to 3% a couple of times as well. In fact I went to 3% back in January on a trip, because my car would not charge past 90% due to the interim recall software.
I do think those few people would be the major exception for a number of reasons:

If you never went below 30 or above 90 you have likely never once taken a long trip in the Bolt. Or even a medium trip I guess.

If you have never went above 90 you are likely a "battery" person who tries to protect the battery or a hill top parking person. Either way, GM never told people not to charge to 100% till after the fires started occurring, so many people would charge to 100 routinely, seemingly with Chevy's blessing.

Similarly, until recently Chevy/GM never told people not to charge below a certain point. Some would, some wouldn't, but it wasn't recommended. And for many the Bolt is their first EV. They likely treated it like an ICE. Fill it up, run to empty, fill up again.

added note: I am a battery person and always charged to 90% from day one. But there were a couple of trips I took where I changed the charge to 100% I would also routinely run down to 30% or a bit below before charging. I always worried about over charging, never about undercharging (though I only hit a low battery warning once or twice (again on a longer trip). We were never told till recently to "baby" the battery, so I would think the number of people would always and forever kept the battery between 30-90 is very very low. I mean we bought our Bolts for the range, right? Otherwise I would just run a 2016 Nissan Leaf :)
 

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I do think those few people would be the major exception for a number of reasons:

If you never went below 30 or above 90 you have likely never once taken a long trip in the Bolt. Or even a medium trip I guess.

If you have never went above 90 you are likely a "battery" person who tries to protect the battery or a hill top parking person. Either way, GM never told people not to charge to 100% till after the fires started occurring, so many people would charge to 100 routinely, seemingly with Chevy's blessing.

Similarly, until recently Chevy/GM never told people not to charge below a certain point. Some would, some wouldn't, but it wasn't recommended. And for many the Bolt is their first EV. They likely treated it like an ICE. Fill it up, run to empty, fill up again.

added note: I am a battery person and always charged to 90% from day one. But there were a couple of trips I took where I changed the charge to 100% I would also routinely run down to 30% or a bit below before charging. I always worried about over charging, never about undercharging (though I only hit a low battery warning once or twice (again on a longer trip). We were never told till recently to "baby" the battery, so I would think the number of people would always and forever kept the battery between 30-90 is very very low. I mean we bought our Bolts for the range, right? Otherwise I would just run a 2016 Nissan Leaf :)
I agree that never is probably rare, but infrequent might be, well, more frequent (especially for deep discharge)? It depends on when the person purchased the Bolt and the individual use case. For example, anyone who purchased a Bolt since March 2020 did so in the midst of a pandemic, when commuting and car trips might be significantly reduced.

I think it's also more likely that people charged more often to 100% than discharged below 30%. Range anxiety is a thing, and it will tend to result in people buying more range than they need (ie Bolt vs Leaf) and having a higher average state of charge than they need (ie not waiting until 30% to recharge).
 

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This article touches on swelling that occurs in Li-Ion batteries: Why Do Lithium-Ion Batteries Swell?

So, BMS updates might be in order. When SOC is low, limit it to a lower current (trickle charge) until SOC reaches 30-40%, then ramp it up till SOC approaches 85-90% and start ramping it down. For those who ask, is it better to use L1, this sure seems to be true, at least when SOC is deeply depleted. It might also be true that aggressive regen at low SOC may be a problem, so BMS updates to reduce regen at low SOC, like at high SOC might be in order.

The point is, in the presence of cells with defects, deep discharges are stressful, as is topping it off. Over time, regularly deep cycling the pack may contribute to failures caused by manufacturing defects. In other words, you are exposing the defects to a greater frequency of stressful conditions. That is not to say never go into the extreme zones, but minimize doing so. Theoretically, the risk is lower if there are no defects in the cells, but the defect rate is still uncertain, so it seems wise to follow the spirit of the advice.

So the advice is not to never charge to 100%, or run the pack below 30%, but to limit these extremes "out of an abundance of caution". Further, moving the car from your garage has no effect on the fire risk, only on the severity of the event in terms of other property that might be damaged by conflagration.
Thanks. Now I KNOW I’m a loser.

Because I already read this article….



Sent from my iPhone using Tapatalk Pro
 

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in which thread are we all discussing the latest fire in Georgia?

 
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