wraithnot
Model 3 VIN #2942 Model S VIN #5785
Sounds like a failure of something like the DC-DC converter that converts pack voltage to 12vdc for the car's electrical system. If it quit working the car's electronics would drain the 12V battery...
Is this converter in the pack? I know they do not let the service centers open the pack so it all gets replaced...
Or it might just be a fuse in the pack on a circuit that sends pack voltage to an external DC-DC converter. Again they do not let the service centers open the pack so it would all get replaced even for something as simple as a fuse...
When I had my HV battery replaced due to failing to charge the 12V battery, the paperwork said "Replaced 12v battery for low voltage after high voltage interlock loop failure". I'm guessing that the "high voltage interlock loop" that failed is located within the battery pack and must be working properly for the DC-DC convertor to charge the 12v battery. But that is speculation on my part.
I have VIN 5785 and had a "B" battery pack. The replacement battery has a different part number (although it still ends in B) and can supercharge at 120 kW. The replacement battery range charges to a few miles less than the battery it replaced (257 for the replacement battery and 262 for the original a few days before it was replaced) so I wish I'd known at the time that they allowed sranger to get his original pack back after the repair. But it's not enough range loss for me to get too bent out of shape.