Share your experience!
You would need to either return your device to the place of purchase or contact Xperia care as we are unable to give official answers, We would be speculating on matters pertaining to warranty http://www.sonymobile.com/global-en/support/contact-us/
Hi guys, how do you check your battery health? Is it normal if your Z2 sometimes drains faster in Standby Mode? This happens at least once a day, where the battery suddenly drains fast in standby mode, but is back to normal suddenly.. And nope it's not a third party app. Thank u 
The best way to check if a 3rd Party App is affecting the running of your phone is to run your phone in Safe Mode for a while & see if the same happens......ive added the link for you :smileysmileywink:
http://talk.sonymobile.com/t5/FAQ/How-to-boot-your-phone-into-safe-mode/m-p/348008
Hi dandy63 :), thank u for your responce, but it's not a third party app, cause I had the same problem when I booted into safe mode 