My N900 has multiple problems, one of which is charging. After fully charging it and unplugging the usb cable it says that it's still charging. It'll keep doing that until it runs flat!
If I have to turn it off for any reason I can't reboot it unless I have a charger plugged in (it just goes into a boot loop). That is a problem also since sometimes it won't recognise that a charger is plugged in (either the wall charger or the 2 car chargers)

I'm about ready to throw it at a wall!