The car I just bought has a USB connection and the sound system is compatible with an ipod.  The music sounds great, I can select songs, albums, or playlists on a touch screen, it even displays album covers.

At first I was just leaving the ipod plugged into the USB port but if I leave it that way overnight, the battery in the ipod goes dead.

I'm wondering where the power drain is.

Right now, I'm taking it with me when I'm parking overnight but unplugging it changes all of the settings on the sound system back to default.  The same happens if the battery goes dead.  I'd like to be able to just leave it alone.

Has anyone else had this sort of problem?