Woke up to the '12 volt battery needs servicing' warning this morning. 23 months old, 23k miles. Had the LTE upgrade installed 10 days ago then the car sat in the garage for the last week while I was on the East Coast for Thanksgiving. Don't know if either are related. Car runs fine, Tesla looked at the logs remotely, said the battery was at 14 volts and I wasn't at risk of a non-starting car in the near future but that I should replace the battery in the next few weeks.