Xperia Z5 :: Battery Drain So Fast Even With Stamina Mode On

I received my phone week ago i notice that every thing works fine but battery drain so fast. Even with the stamina mode on and brightness is very low and i also set the auto brightness. I also updated my phone to new version but it still same I also clear the stamina mode app settings and when i checked that which app using more battery there no app there. I install same apps which is install in my z3 but z3 give atleast 1 day or like 20hrs battery the why i use it normally the way I use it .