I have terrible battery life on my iPhone 5 (iOS 8.1.3). Maybe I found who's guilty: not using the phone that much, I found mail to take up to 56% of my battery in background. I don't have push mails on, it's on a 15 minutes refresh. What can I do? I have 5 addresses. Thanks a lot. PS: low signal is not a stable condition. Just this time.