I've had my tab s 10.5 for almost a year now. This past month my battery has been draining fast going from 100% to 0 in a little over an hour. When I first bought it I would get good battery life would be able to watch 2 movies and still have about 50%. Just sent it in since it was still under warranty just received a email that they replaced the charge port. Not sure how the charge port has anything to do with the battery life but hopefully when I get it back I don't have the drain issues.
Let me know if it helps. I have a fast drain issue as well asa charge issue were unless I power off my tab it wolnt charge and keep discharging. I tried numerous cables and plugs.