I'm in the Sierras at our time share and it was 17F this morning at around 5:00 AM. The car is plugged in but only to a 115 volt outlet. It was charging all night long and the charge went from 50% around midnight to 65% this morning when I went out to check it. Will the car use the battery heater to keep the battery from getting too cold when it's only plugged into a 1.2KW shore power? Is it bad for the battery in any way to sit overnight in this temperature? Does the answer change if it's not plugged in?