The car sat in the garage for three days without being driven or turned on. The battery was completely drained after the third day. The multimeter measured about 8V. The battery voltage should be over 12V. After jumping the battery and running the engine at idle for a while, the battery voltage came back up.

Dealer could not recreate the problem even after letting it sit overnight. We do not know what cause the battery to drain. Nothing in the car seemed to be on (no interior lights were on). Could it be that the infotainment system's Bluetooth stayed paired to my phone the entire weekend since it was close by and drained the car battery? Not sure. I tried many things to try to recreate what I did before the battery drained but nothing seems to be on long enough to cause a battery to drain after shutting down the engine. After about a month later, I have not had the issue again. But I am afraid that my wife will be stuck somewhere because the battery dies again at an inopportune time.