This is literally what my battery life is like.
I charge it for a while (until it's 100%) and then I go use my phone to do something like play a simple game and bam. It turns off on me and when I turn it back on it's 2% and it was only a minute. It was fine when I first got it... Was it because I downloaded too many apps? I deleted almost all of them so shouldn't it be fine now? I've had this phone since mid-May. Yes I put the screen brightness on auto.