For a number of reasons I often do not charge overnight when I park my Model S 90D in my garage. Tesla recommends to have the car "always plugged in when not in use". But does it mean *plugged in AND charging*? Is it ok to cancel charging after plugging in overnight? I know if you plug in and cancel charging, there is still the vampire drain, as I loose 1-2% of battery charge overnight. So, what's happening when the car is plugged in, but charging is cancelled? Is the onboard electronics maintained by the battery or the external power?