Been having this problem since ios 6, now im on 7. Tried hard resetting, deleting and adding mail accounts, i set up my phone as a new one when updating to ios 7. Deleted all apps one by one, the problem is still here. Now i have facebook and youtube only. I dont have push or fetch, icloud account used only for backup nothing else. Messages phone and facebook in notification center. Location services off all the time. No apps running, i close them when i stop using them. Always closing safari tabs. Anyone got some other solution?