I currently have mine at 50%. As in, only 50% of the screen works at 100% brightness.
This is all the time because there is something else wrong with the power detct function and it thinks it's always on mains power.
grr.
I blame harry potter. the last thing I was listening to was his audiobook and next time I got in the car, wham.
I am incontact with Hugo about all this.