The most common reason people give for wanting to idle all night is to run the heater or air conditioner.

In the long term it is more practical to heat with a propane heater before bed, and a contact heater and appropriately-rated sleeping bag for sleeping. People in very cold climate may want to install a vented heater for overnight heating.

In addition to the problems listed above, idling to charge is hard on the alternator. The alternator depends on sufficient RPM to spin its cooling blades, and airflow from the forward motion of the vehicle. Neither cooling method is available while idling.