Sony Xperia E4 battery life?

[Jonathanprt]

Hi.  I have just bought a Sony Xperia E4 phone and am querying the Sony claimed standby time.  The number of hours they claim is about 27 days of the phone being on continuous standby.  However when I charge the phone from empty and then turn it on again it says battery is 100% ( as it should be) but when I go to Power Management it says that the phone has 15 days 23 hours left on standby and 19 days 4 hours left on standby if I use the Ultra Stamina mode.  Is this normal?  I think personally that it must be as this is the second Xperia E4 I have had and the same concern with the first one too.

Thanks for answers.

[Uliwooly]

@Jonathanprt

There's nothing wrong with your phone, the more you use it the better the phone can predict battery life, also, there are myriad things that affect battery life. 

[Rickard]

This sounds normal. As uliwooly says, the estimated battery time displayed in the phone is based on how the phone has been used previously. So if you use the phone more, it will estimate a shorter battery time the next time you charge it.

Network reception, enabled features, installed apps and running services will also affect battery life even when it's on standby.