Got my model 3 in July, 2018, and just yesterday got the messages about 12v battery unavailable and deteriorated, car shutting down unnecessary functions, etc. Of course I didn't know what this all meant as I was driving, but owners manual stated car could shut down unexpectedly. Just to share my experience, I booked a mobile visit to change the battery, that was a week away, then tried the local service center in Burbank CA. They had me bring the car in at 8:45 pm last night (same day as the warning messages), tech said the car could be ready at end of next business day, but couldn't promise, then I got a text at 11:20 pm that the car was done. Went in at 8 am this morning, picked it up and on my way. Just big kuddos to Burbank service center, they got me in right away, fixed the problem while I slept and got me on my way to be on time for work. all for $121.00...and this was the original 12Volt, got about 4 years out of it, so that is a win in my book too.
