FYI i only have one battery and it's a Kinetik HC1800.
Tonight I drove about 6 hours in the car on and off; i'd say 90% of the time, the car was on.
At the end of the night, the car idled at 13.0v, made it up to 13.8v at 2krpm, and rested at 12.45v when the car was turned off. (lights were on)...