If you did the update to IOS 7, and/or 7.0.2 OTA (Over The Air) and are now expreiencing poor battery life, try this: Settings, General, Reset All Settings and Data, it fixed my Battery Life Problem after updating to 7.0.2 OTA.
Sorry to hear about that. This possible fix was something that I previously read about on an Internet Article somewhere and it did work for me but I guess it does not work for everyone.