What I did was plug up my ipad to my computer, pressed the home button twice to get siri and then held down the home and sleep buttons at the same time for about 7 seconds. My ipad then showed the apple logo for about a minute and came back on. Prior to this, my mini would not power down or show that it was charging. Once it rebooted it showed the correct amount of battery power and worked fine. Not sure if this will always work, but hopefully this forced reboot will make things easier in the future.