Chevy Bolt EV Forum banner

1 - 15 of 15 Posts

·
Registered
Joined
·
21 Posts
Discussion Starter #1
I understand that there's been a significant change, or upgrade, to the main battery pack on the Bolts.

The VIN breaking point, supposedly, is VIN 1G1FX6S06H4163254

Our 2017 Bolt VIN is 1G1FX6S06H4141748,

What are details surrounding this, and is Chevrolet doing anything that involves a Service Bulletin and main battery pack replacement?

Oldskybolt
 

·
Registered
Joined
·
2,570 Posts
Main change in battery from Weber video was the cooling port. But indicated that the newer batteries have fixed some earlier issue. Don't know if they just had a bad batch, a QC problem, or a battery management controller modified. Don't recall see anything official as to what they did.

As far as notification, GM monitors all the Bolts and will send you a love note if the low cell voltage anomaly is detected. One forum member recently had a sudden loss of power without being notified. Others have noted getting the notification before anything happened.
 

·
Registered
Joined
·
574 Posts
My VIN is 1G1FW6S01H4188081, and was built in November 2017. Does this mean I have a battery pack from before the upgrade?

Can Chevy continue to monitor my vehicle? I didn't fork over the money to continue my OnStar coverage.
 

·
Registered
Joined
·
3,753 Posts
My VIN is 1G1FW6S01H4188081, and was built in November 2017. Does this mean I have a battery pack from before the upgrade?
No, you have a newer battery, as indicated by the last several digits of the VIN. The stuff up to the last alphabetic character is metadata that indicates the manufacturer, the factory, the vehicle type, etc. and is not indicative of the build sequence. It's only the trailing digits that are sequential (but not necessarily consecutive).
 

·
Registered
Joined
·
121 Posts
The principle change was for battery maintenance purposes. To keep the technician from accidentally reconnecting the battery coolant lines backwards, GM made the hose ends one male and one female, instead of having two female connectors. Other stuff was relatively minor, in the world of ever-changing battery technology.
 

·
Registered
Joined
·
3,740 Posts
As others have said, there was a change to the coolant line couplers, going to one male, and one female coupler, on the battery, to prevent inadvertently switching them.

The problem with the early battery packs was stated as some cell or cells with low capacity showing up in some packs. This would be a QC, or production problem at LG. GM says the problem has been identified, and rectified going forward. They have been able to catch some of these low capacity cells from readings from the BMS (battery management system). I am sure they were hoping this would catch any failures without requiring an actual recall. There have been a few people caught out, with their cars stalling in awkward or unsafe situations.

I assume one of two things will happen. Either they will skate through with a few people being inconvenienced, and eventually all the low cell packs will be replaced as they fail, or there will be serious situation which will result in an injury or death, and GM will be in a world of sh_t again. I don't expect an actual recall of all the packs produced before the problem was caught. That would be expensive, and would not be good for GM's stock price for a few days. Instead they will do what all large corporations, and most individuals do, when faced with an unpleasant situation. They will hope it goes away. For everybody's sake, I hope that works.
 

·
Registered
Joined
·
574 Posts
It sounds like the battery cells 'fail open' (high resistance and loss of current), which is a safe failure mode where power is lost. It sounds like they do NOT 'fail short' (short circuit), which is an unsafe failure mode where high currents could develop, resulting in heat buildup. An inconvenience, not a hazard.

Given the small percentage of sales that are Bolts, it's unlikely even a total recall of all Bolts would affect the stock price of GM.
 

·
Registered
Joined
·
3,740 Posts
It sounds like the battery cells 'fail open' (high resistance and loss of current), which is a safe failure mode where power is lost. It sounds like they do NOT 'fail short' (short circuit), which is an unsafe failure mode where high currents could develop, resulting in heat buildup. An inconvenience, not a hazard.

Given the small percentage of sales that are Bolts, it's unlikely even a total recall of all Bolts would affect the stock price of GM.
This description does not support you theory:

"We are aware of a small number of early Bolt EV customers who have experienced loss of propulsion. Due to a battery low voltage condition, the car may incorrectly report remaining range at low states of charge and lose propulsion before the customer expects."

More likely, a single cell has a lower capacity from a defective/reduced coating of the active ingredient onto the foil of one of the electrodes, or a problem with the electrolyte. This situation should be caught during the formation charge or subsequent cycling at LG. If there is a low capacity cell, it will suffer accelerated deteriorate over time because of the greater stress from charging/discharging a lower capacity cell in a pack of higher capacity cells. The only way for the electronics to detect a low capacity cell is near the bottom of its discharge, as its voltage will drop off faster than higher capacity cells. The rapid drop off only occurs near the very end of charge on a lithium ion battery. As the cell's capacity deteriorates, this will show up at a higher, and higher pack SOC. I have this exact condition on my 2011 built, electric assist bicycle. After 5 years of use, one of the parallel cell groups, or a single cell in that group suffered from decreased capacity. Under heavy load, the voltage on all cells sags, and it sags more as the cell approaches a low SOC. The BMS will trigger a low voltage cutoff when this occurs. With the failing cell/cells this started happening at 24 kWh used, instead of 30 kWh used. It progressed to 22 kWh used, and now happens at 20 kWh used. I can turn of the bike off, and turn it back on to reset the BMS. If I baby the throttle to reduce voltage sag, I can ease off enough to get home. This stoppage is not an open circuit failure of a cell, but a normal functioning of the BMS. On something as sophisticated as a car they have the option of sending a warning, and reducing throttle function until you can get off the road.

As for stock price, I think that traders are watching car company stocks very closely these days. It isn't enough to build millions of reliable vehicles now. Cars have gone from a commodity to part of the tech bubble. If you are not seen as working on the latest tech revolution your stock suffers.
 

·
Registered
Joined
·
24 Posts
I don't know if anyone has ever posted a breakdown of the Bolt's VIN. Here it is:

My Bolt VIN - 1G1FX6S01H4179555

1G1 = American General Motors
F = Model (Bolt EV)
X = Trim Level (X=Premier W=LT)
6 = 4 Door Hatchback
S = Restraint Type (Presumably Seat Belt)
0 = Engine Type (None)
1 = Check Sum (add up all the alphanumeric characters and divide by 11 - this # is the remainder)
H = Model Year (2017)
4 = Factory ID (Orion)
179555 = VIN of Vehicle

The Bolt's VIN is not sequential as the Ampera-e and Sonic are also produced at the plant. And up until the end of the 2017 model year, the Buick Verano was also manufactured there.

Hope this helps!

Jim I - Very Happy 2012 Volt & 2017 Bolt Owner
 

·
Registered
Joined
·
3,740 Posts
Someone had asked why there would be a problem continuing to discharge a pack with a low capacity cell. Running out a cell and continuing to discharge the pack causes the low cell to suffer permanent damage. Somewhere there are a couple of very good descriptions of what happens. This is not the big problem.

The dangerous problem occurs when you try to recharge a pack with one of these damaged cells. Jack Rickard has actually done this twice in his shop...once with a relatively safe, small LiFePO4 battery on an oak work bench, and once with a 24 kWh Nissan/Renault pack. He new this could happen, but he went ahead and did it twice just the same. Humans Are fallible, as has been demonstrated at least twice in atomic power plant accidents.

http://evtv.me/2015/11/a-dark-and-sunny-sunday/
 

·
Registered
Joined
·
3,753 Posts
I don't know if anyone has ever posted a breakdown of the Bolt's VIN. ...The Bolt's VIN is not sequential as the Ampera-e and Sonic are also produced at the plant. And up until the end of the 2017 model year, the Buick Verano was also manufactured there.
The number at the end of the VIN is sequential in the sense that a higher number means that the vehicle was built later. But it's not consecutive - there can be gaps in the sequence numbers due to some of the VINs being assigned to a different car model.
 

·
Registered
Joined
·
473 Posts
I see that the "recalls' were done, but was the " Get a NEW battery pack" recall done?
I have not had an issue yet but my pack was on order 3 months ago. No call yet but I want to keep my car ;)


Any news ?


Which dealer is it at? I am in MA and bought at Quirk, but live near Mirak in Arlington
 
1 - 15 of 15 Posts
Top