The way android task management works is that it is designed to have some apps running all the time, in order to have them ready to go the next time you open the,, without having to wait for them to open. With what you are describing, it sounds like your phone could be automatically reopening those apps after you close them, causing your phone to stay awake after you turn the screen off, and draining your battery

 

Well, you don't need to close all your apps and clear out your memory. At this point (android 4.1 for your phone I believe) android is good enough at managing it's own memory and works better when the RAM is close to full.

 

Yeah killing apps is pointless and will make the phone use more battery in most cases. Not sure if thats the full reason for your problem but its definately part of it :thumbup: