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Has it been announced that it will shut down in the case of fault detection? Seems like another way to do it would be to limit the charge level to a safe level (and passively bleed off excess charge if it is above that level when the fault is detected) so that the car can be driven to the dealer for repair (of course, a warning message would also have to be displayed telling the owner to take it in for repair). After all, if 95% is safe now, bring back the 95% limit if a fault is detected would still be safe, right?
The "shut down in the case of fault detection" was a suggestion on my part. I suppose the action taken at detection would depend on the level at which a warning/action would be given/taken? If a fault occurs it would be too late to "limit the charge level" don't you think? How would the "bleed off excess charge" be implemented? If it could be done I think that would be a wise choice.
 

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I imagine that if the condition arises, it will cause the CEL light to come on and a message to be displayed. I don't imagine that they expect an immediate peril to be present. Then again, there might be various warning levels that escalate up to "run like **** and call 911"

I would think that GM has to be pretty convinced that this condition will not escalate into a fire super fast!
I can't speculate on the level at which action should or might be taken. I also have no idea how fast or dangerous the reaction might be. I think shutting the car down might be the safest choice? I would imagen once that occurs the car would be vacated thus reducing the chance of personal injury's.
 

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How would the "bleed off excess charge" be implemented? If it could be done I think that would be a wise choice.
Could be done similar to the way that it wastes charge from stronger cells when trying to balance them. Or it could just run the cabin heater. Of course, if the car is being driven at the time, it may not have to do anything special if the driving uses up enough to bring it down below 95% by the time it is parked.
 

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I can't speculate on the level at which action should or might be taken. I also have no idea how fast or dangerous the reaction might be. I think shutting the car down might be the safest choice? I would imagen once that occurs the car would be vacated thus reducing the chance of personal injury's.
Unless a battery fire is actually occurring, shutting down while driving may not actually be the safest way to handle the fault. Indeed, continuing driving may help reduce the charge level to below the >95% danger zone. Also a shutdown in the middle of a high speed freeway may be dangerous for other reasons.
 

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Someone on a Facebook Bolt group is claiming they received the update and now the charging curve matches the 2020. No step downs. Has this been confirmed? Interestingly, the same thread points to a new "supposed" Bolt fire as reported in a Tesla FB group but I suppose that's a topic for another thread. Whatever the cause, the attached photo of a burning house/garage is a little troubling. That would be spectacularly bad timing if it is a Bolt.
 

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Since the problem occurs at/near full charge, I would bet that if a fault is detected it will be during charging, not driving. It will probably stop charging and give an error code. At that point it would probably either A: Refuse to start and have to be towed to dealer, or B: Allow start with a notice to service immediately and may refuse to charge again until serviced. I would guess A.

However, I'm still of the opinion that it's not going to be possible to detect an actual fault with software any more than you can update the software in your cell phone so you can use the camera to take pictures of planets around distant stars. There's physical limitations involved that software can't fix. Although it's impossible to know for sure without knowing the root cause. If it's dendrite growth or improper packaging of cell modules, allowing too much cell expansion, you can't detect that with software until it's too late.
 

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Seems like another way to do it would be to limit the charge level to a safe level (and passively bleed off excess charge if it is above that level when the fault is detected)
Bleed it off to where?

Since fires are from massive current flowing with I2R heat across separators from dendrites or folded tabs, etc., the only other path the electrons can flow thru is anode to cathode. You would have to switch in a new power load, and a high robust load, to get the bleeding done. That new load could be an air-cooled nichrome wire coil or ceramic encased (heavy) resistor, maybe using the steel body as a heatsink (heat transfer), something to turn electricity into heat elsewhere, just to avoid internal shorts thru the separator. Similar in concept to the pressure relief valve on a home water heater.

Even if you just wanted to dump a small amount of current overboard, you would still need a switch to a new load.

Has it been announced that it will shut down in the case of fault detection?
The only thing that can be done is to stop charging if battery voltages behave strangely. The algorithm must be able to detect the onset, the initial hints, of future massive runaway internal shorts.

If they run a pattern recognition algorithm (simple heuristics or neural networks or vector dot products, etc.) to correlate charge or discharge anomalies with future fire events, this could be the solution they have implemented in this recall "fix".

Since preventing fires is in the interest of the public, trying to keep from burning adjacent cars, people, buildings, insurance losses, etc., & trying to build confidence in EVs amongst drivers, passengers, fleet managers, and government legislators in EVs going forward, these algorithms should be analyzed in research papers by NREL, Argonne, ORNL, INL, & others, not kept secret.
 

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Bleed it off to where?

Since fires are from massive current flowing with I2R heat across separators from dendrites or folded tabs, etc., the only other path the electrons can flow thru is anode to cathode. You would have to switch in a new power load, and a high robust load, to get the bleeding done...
How fast would the car need to bleed power? Would just running the cabin heater and AC help? That would be about 9 kW.
 

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Unless a battery fire is actually occurring, shutting down while driving may not actually be the safest way to handle the fault. Indeed, continuing driving may help reduce the charge level to below the >95% danger zone. Also a shutdown in the middle of a high speed freeway may be dangerous for other reasons.
I agree. I think the probability of whatever the indicator might be occurring while using the battery is unlikely. I was thinking that whatever the trigger would be it would be more likely when the car was being charged or shortly thereafter, but your point is well taken. Safety first.
 

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Had my recall work performed today. Dropped my car off at 8:30 (scheduled) and picked up the car at just after 4:00. I received two OnStar Notification emails concerning problems with the car (I assume when the updates were taking place - one about Engine and Transmission System the other electric drive unit) at 3:08. So be prepared for that in your inbox.

When I dropped off the car I mentioned to the service desk that I was aware of the work that needed to be done and the various measurements which were going to be taken to determine the health of the battery system. I requested a copy of all of that information which they gladly provided. What I got was the entire N202311731: Safety Recall - High Voltage Battery May Melt or Burn - (Apr 29, 2021) document (carries Document ID: 5823035). which runs a full 12 pages.

On Page 5 are the values they measured:
"Hybrid / EV battery Voltage Sensors Average (Value A) 3.56
Minimum Hybrid / EV Battery Module Voltage (Value B) 3.54
Value A - Value B = 0.02

If the voltage difference is less than or equal to 0.08V, proceed directly to Procedure 3 (they underlined this and went to that point to finish - this starts on Page 6).

I also received copies of the Programming Receipt for both the Body Control Module and Hybrid/EV Powertrain Control Module 2
Those are timestamped shortly after the OnStar notification at 3:17 PM and 3:37 PM

As always I'm happy with this dealership, the information they provide, the calls and willingness to answer questions. Hope everyone else has a great experience on their end.
 

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On Page 5 are the values they measured:
"Hybrid / EV battery Voltage Sensors Average (Value A) 3.56
Minimum Hybrid / EV Battery Module Voltage (Value B) 3.54
Value A - Value B = 0.02
Our 2017 Bolt LT with 37K miles has an average cell to lowest cell delta of under 0.01 volts. I guess we won't be getting a new battery. :(

back at 12.18 pm.jpg
 

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Our 2017 Bolt LT with 37K miles has an average cell to lowest cell delta of under 0.01 volts. I guess we won't be getting a new battery. :(

View attachment 34778
Well, I guess that cements my decision to keep my 2017 Bolt forever. I was inclined to do that anyway.
If its going to be worth diddly-squat as a sale or trade. I'll just drive it into the ground. That'll be long long time from now as I've just turned over 24,000 km (about 15,000 miles). And I still get a real kick out of it. Anyone tried to add a front end stabilizer bar to the stock setup ? Might decide eventually to do some rallying! :cool:
 

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Just dropped off the car. I asked if they could also update the firmware on the entertainment system but the guy told me that would be $145. I don't understand why these dealerships try so hard to drive customers away.
 

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Just dropped off the car. I asked if they could also update the firmware on the entertainment system but the guy told me that would be $145. I don't understand why these dealerships try so hard to drive customers away.
Sorry off topic, but what firmware update to the entertainment system are you referring to?
 

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Sorry off topic, but what firmware update to the entertainment system are you referring to?
Right. One Infotainment update in 3 years, and it was customer installable. Dealer is right to charge for doing the update for you, their time is money and the warranty would not cover this.
 

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Right. One Infotainment update in 3 years, and it was customer installable. Dealer is right to charge for doing the update for you, their time is money and the warranty would not cover this.
Ha...okay. So much time wasted plugging in a USB cable and pressing a button. Especially when it may fix actual PROBLEMS I've been experiencing.

After I dropped off the car, someone from the dealership texted and I responded with my concerns. She said the entertainment system glitches should be covered under the three year warranty and she would pass on the info.

For the other poster, the update is covered by tech bulletin: #20-NA-119 (bringing the 2019 to version 34.9.2).
 

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Our 2017 Bolt LT with 37K miles has an average cell to lowest cell delta of under 0.01 volts. I guess we won't be getting a new battery. :(

View attachment 34778
Mine is a 2019 and I'm just over 35k miles at the recall fix date, and that's after not driving hardly at all for the last year.

Also, I've never got Torque to work with my Bolt... perhaps I should go try it out again as I use it for my ICE vehicles without issue. The custom PID table never seemed to load properly for use with my Bolt.
 

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Well, I guess that cements my decision to keep my 2017 Bolt forever. I was inclined to do that anyway.
If its going to be worth diddly-squat as a sale or trade. I'll just drive it into the ground. That'll be long long time from now as I've just turned over 24,000 km (about 15,000 miles). And I still get a real kick out of it. Anyone tried to add a front end stabilizer bar to the stock setup ? Might decide eventually to do some rallying! :cool:
I put the Eibach Pro-Kit on my 2019 Bolt, and the new springs are great. I can't believe GM didn't put something similar on the Bolt as stock.

I also replaced the oem tires with Michelin mxm4...the crossclimate 2 weren't out yet or I would have used those. Much better overall car now.
 

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As I posted in another thread, Vehicle Detail Search | NHTSA suddenly has a drop of 7 new documents for campaign 20V701000. It was at 19 for ages, then a 20th got added recently (submitted April 29th) and now there's 27. It was only 20 last night.
 
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