My iPhone keeps dying at 30-40%?

It this a battery malfunctioning? I sent in a diagnostic test to Apple online and they said my battery passed the test and it's working fine. Any fix? I already reset this with the power and home button but no use! Should I trade in for a new one?

Li-ion batteries fail all the time

  • I have an iphone 4, battery keeps dying? How do i stop my battery from dying even though i aint even using it. I keep my cel in my pocket while i'm working, but when i go take my break its already at 50% but it was 100% when i started working just 2 hours before
  • My iPhones sound keeps Turing keeps turning off? Well for a while now my music will randomly turn off and I go to the app and there's so sound bar what so ever… And then I restart my phone and my music or keyboard sound still won't turn on… What do I do now?
  • My iphone battery keeps dying and I'm not using it? It is connected to the Wi-Fi in my house, so not 3G. It will be 100% before I go to bed, then by the time I wake up in the morning the battery has died. The battery is draining when I'm not using it? Today I charged it to 95%, was home for a couple of hours, didn't use it and now it is at 4%?! What is wrong with it? I don't have any new apps or anything, it's never done this before!
  • Iphone keeps dying when I take it off charge? Charges normally and as soon as I take it off charge it switches off instantly. Any fixes or do I have to take it to the Apple store?