Ive noticed something with my wifi since I started getting poor battery performance. My battery hasn't given me any trouble till about two weeks ago. Many problems already addressed here but I didn't see this problem mentioned anywhere. When I am at home I have my wifi on, and when I leave the house I turn it off. It's a habit I got with my iPhone (made the battery last longer). When the wifi is on and I am connected to my network I see the connected symbol at the top of my screen. When I lock my phone and then wake and unlock it, it has to reconnect to the network. It doesn't matter if it's been a few seconds, minutes or hours. With it constantly connecting and disconnecting that has to be draining the battery and it also makes me think that when the phone is locked that it isn't connected to wifi which means it's using data (for email pushes, background tasks etc.) I'm just trying to narrow down what is pulling battery power when I'm not actively using my phone. Twitter was a big culprit so that got uninstalled as well as App Social.