Ok, so this has been happening 2 or 3 times a week ever since I updated the software to IOS 7. Whenever I enter an area with sub-par cell phone service, like the gym or my basement, my iphone will sometimes shut off on its own. Whenever I try to turn it back on there's an icon with a lightning bolt and phone cord, which I assume means that the battery is close to death. However, it will die whenever my phone says it has a battery of 20, 30, or sometimes 40%. When I get home and plug it in, the phone will come to life, displaying the partially full battery that it had before it died, as opposed to showing 0 or 1%. I'm not really doing anything that drains the battery, like surfing the web or streaming video. I usually am just listening to music. My best guess is that my phone is draining battery trying to find service, however, I don't think that would explain why it shuts off so sson, instead of fully draining the battery.
Is there anything I can do to stop this? Has this been happening to anyone else? Any feedback would be appreciated, thanks