I've been having some problems with the WiFi drain issue that some others have posted on here, but yesterday I had a new problem with my battery which may be related but may be entirely different. My battery was around 50% when the phone suddenly switched off (first time this has ever happened). When I switched it back on, battery was at 1%. I tried to quickly finish what I was doing (Uber app) expecting the phone to turn off again, but it didn't. I looked at the battery and it had gone up to 5%. About 15 mins later it was up to 20% and climbing, as if it was on charge. Today around the same time it happened again, but I wasn't using Uber. I can't see how to post screenshots, sorry all new to this forum!