Hi again Claus,
yes one night should suffice. Usually the loading time is around 5 hours or so.
The display will not show fully charged afaik. But you can check the battery status in the setup menu (press Stand-by + "go" Button).
Try to move the Beo5 a little on the charger to the left and right. If this does not work, change the USB cable.
Do you by any chance use a USB hub? If so, try to connect the Beo5 directly.
I am sure your dealer will allow you to test a different table charger to see if that is the problem.