How much time systems remain operational with the car parked and switched off?

[Fly4ever]

In later years most - if not all - cars allow only a little time for the systems to remain on after the car has been switched off.Mostly will depend on the battery health, letting you hear to the radio for example or playing with the moving map or whatever,only for a while before the car shut everything down as a protecting measure for the battery.What's the deal with the Macan?How much time "lets" you listen to a tune for example on the radio or a USB device while parked,if letting you at all...!!?
Also,is it possible to hear wireless streamed music from a device to the car audio system or it must be connected to the USB port through a cable?