Read these below. When I got my new phones, pictures took a couple days to sink back up from iCloud. As such the wi-if was running constantly. I wouldn't test battery life until the 20 minute standby test showed little to no drop. This test is mentioned in the articles, so I won't bother explaining. At the point the standby test shows back ground updates and loads are completed is when a real test for normal battery life can be tried.
You most likely have an app that is hung up. A software problem. This is mentioned in the articles below. Again read them for yourself. It is highly unlikely you have a hardware issue, as most battery problems are caused by software that is hung up and running your radios trying to update.
If you don't want to believe me or what others have said, then don't. I don't really have to prove myself as I don't care if you believe me or not. I'm just trying to help. By the way, spending 20 seconds in Google search found these articles. Probably quicker than all your replys asking for proof and back up from people trying to help you.
http://www.imore.com/battery-life-problems-iphone-se-heres-fix
https://discussions.apple.com/thread/7252649?tstart=0
http://www.redmondpie.com/tips-to-fix-ios-9-battery-life-issues-on-iphone-and-ipad/
Go down to "Toggle iCloud Keychain"
http://www.payetteforward.com/why-does-my-iphone-battery-die-so-fast-heres-the-real-fix/