I can only add a similar answer to the one I just answered for another guy/gal a bit further up the page with similar issues,,,
Make sure you actually plug that charger in - PROPERLY. I have had numerous similar experiences with my tablets. I usually charge both my tablets on my bed from an extension lead with a double adaptor and for some unknown reason I am forever either walking over that extension lead and slightly pulling it out, or not plugging the lead in properly into the wall socket,, and each time I notice the tablet(s) don't appear to be actually charging, but are actually draining even more power real fast. I then look straight at the wall plug and always notice that there's a gap between the plug and the socket indication it's not plugged in properly. One push and all seems to be ok.. I am always doing the same thing...
Al