I had this problem about a few weeks ago. I let it switch off completely first then put it on charge. It kept charging for hours but now there's no problem. I think there's been some battery trouble with pr1.2 if that has to do with anything. In fact my device had been on charge and i was browsing the internet on it when it just beeped low battery and switched off. Leave it alone for some hours to charge fully and then see if it happens again