Thanks! I had a dealer do the official battery pack test last year before the battery warranty expired, which was 10 months back, they came back with 23% capacity loss, after using it for driving this winter it looks to be the end. With the pack crapping out with 2 bars over half and 39 miles on the gom, even if it can be un-bricked, that means this car is only capable 20 miles of range, it's 17 miles to work, add in heat or ac and the fact that charging there is impossible and this is the end for Sparky, it's too expensive to maintain tags and insurance for it to only be able to go around the neighborhood.
The BMS is very unfriendly to drivers when it manages weak cells. It forces you to have dealer interactions which have tended towards buyback (usually under warranty) or whole battery replacements for an extremely unsustainable price point. Replacing 1 out of the 6 modules isn't a supported procedure for the dealer (3rd party only) and GMs part catalog has no module level searchable part numbers because that's not how they envisioned these cars would be supported...
I don't know if you have much experience pulling power out of with weak lithium cells, but it's often overlooked that in addition to the capacity loss, the ability to extract power quickly drops as well, which Randy pointed out drivers find out usually up hills and at or below 20-25%.
There are certain rules we've come up with to deal with the BMS's watchdog, which is what is killing off Sparks. That is the HPCM2 which the BMS reports this very specific event, and the HPCM2 maintains a hard to clear "do not resuscitate" error code. Did cells go through some irreversible damage? No. Is it dangerous to use again? No. Is it meant to be a nuisance? Absolutely.
A guide to avoid bricking your car due to weak cell freakout:
After losing your 3rd bar, as a driver, maintain a power limit on your cells. If you have 77% capacity remaining on 18.2kWh new packs, 1C (1x capacity) is about 14kW on the dash. This ensures maximum energy efficiency so slow chemistries can keep up and deliver power at their highest cell voltage, and at low states of charge (25% and lower). Throttling power ensures the individual cells are working above the watchdog's 2.5V freakout zone.
Outside of this range, it's safe to use more power, but be wary of how long you do it for because the chemistry will become tired and the voltage will sag, and usable energy will reduce for that discharge cycle.
Does that make sense? High efficiency is below 1-2C. Higher for the Spark EVs high discharge pouch type cells it should be 3-4C but weaker cells have lost the ability to discharge without dipping into low voltages that scare the sensitive watchdog computers. The degraded capacity can be fully extracted if drivers respect their limits.
You don't need to avoid driving under 20% but you should keep advanced scan tools on you and you should take care to work with these electrochemical cells. I'm sure the Bolt experiences this too, but they have 50-60kWh of capacity, so low power discharges are rather trivial.
