Was out flying a GS mission over the water today and had that horrible sinking feeling that my Phantom was also on it's way to doing some sinking as well. I had 100% battery before the flight but have had a few problems with this battery lately. I noticed previously the percentage started dropping really quickly when it hit about 50%. It was only a 3 minute mission so I thought it would be ok. It was about 400m out over the ocean and on it's way back home when the battery power just plummeted and it started to auto land. ****..... At this moment all I could think about was how much I would miss flying until I could afford another quad and was instantly heartbroken. I noticed on the FPV that the bird was on its way down and seemed to be moving further away. I switched down to RTH and it obviously thought it didn't have the power to get home so still kept descending. I went to Atti mode and punched the altitude and hit full speed back to land while guiding it back through FPV. Litchi was telling me there was 7% left as It screamed back into sight and I left it to auto land. I checked the battery just then on the assistant though and said it had a 65% charge. I don't get it. This battery has only had 45 cycles, has 85% life left, has been fully discharged to reset twice, no bloating and all three cell levels are almost the same(middle one out about 20). My other battery has been cycled more than this one and is way more stable. What is going on guys?