When disconnected, my battery will sit at around 12.8 volts. I tested the current draw by disconnecting negative terminal and then using the multimeter in series. It read -1.8 amps, which is a ton. I also tested the voltage after immediately turning off the car. The voltage drops quickly from 14 volts to 10.5 volts within 30 seconds, you can watch the numbers fall.
What could cause a draw this large?
Sounds like you have a bad battery. I’d test that first. A 1.8 amp draw might be normal for your car right away, some cars take 30-45 minutes to get the modules to sleep before you can accurately test for a draw.