Hi guys, I got a new S4 yesterday, as I fancied a change and will be giving my iPhone 5 to my father. Initially, I am very pleased with the phone, it will take some getting used to. However, this morning I now have 40% battery left, with 2hours 20mins usage on the battery, 74% of this is from the screen. I've only been using it for browsing on chrome and texting on WhatsApp... Surely this isn't normal? Any advice would be great. Thanks.