Yep thats what happened with mine.
i sent it back to Apple and had the battery replaced. I tried to make an appointment at the apple store but it said it wasn't available, maybe they don't have the parts for them in store.
Truly a night and day difference. When I leave for the day I don't have to think about bringing my charger (although I still do sometimes in case of an emergency)
I'm on a three year old iPhone SE that I recently had the battery replaced in (An incredible use of $50 if anyone is fining their phone dying all the time)
I am really tempted to get this. I love the small form factor of my SE but I have large hands and the bigger screen might be a bit nice, and I really wish the camera was bit nicer on my current SE
Truly a night and day difference. When I leave for the day I don't have to think about bringing my charger (although I still do sometimes in case of an emergency)