Fast battery drain
Hi, my iPhone 6s has been acting weird lately. I got this 6s brand new in 2015, since then I’m on my 2nd replacement battery from apple store and it’s still 89% remaining life. 2 days ago, the battery would frequently showing less than 10% battery even though it was fully charged 1 hr ago. Upon restarting the phone, it would again show 90%+ battery, but the battery would still drain very fast.
last night I had the phone charged to 100% before going to bed. I woke up this morning about 8 hrs later with the battery at 1%. What’s wrong with my phone? What should I do?
iPhone 6s, iOS 15