IPhone 5 :: IOS 7.1 / Battery Drain Random Shut Down

I have an iPhone 5 running iOS 7.1. Today I left the house at 8:30 am with 100% battery. I had a breakfast meeting and put my phone on the table while we ate and did not use it. By 10:00 my battery was down to 3%. On other occasions, the phone shuts itself down while there's still 30% power, and I have to plug the phone into a charger to get it to restart. When it restarts, it shows >30% battery. I've been struggling with both issues for months (as have numerous friends with iPhone 4, 5 and 5s). I do not believe it is a hardware issue, but rather, an issue with iOS 7, which is when the problems began for me. My old iPhone 4 running iOS 6 would go an entire day of heavy use on a single charge (and usually had juice to spare). There is a serious power management problem with iOS 7 and I'm deeply disappointed that Apple hasn't addressed it. Â

You can conserve battery life by switching off cellular data, closing apps every time you finish using them, and other tricks mentioned by users here, but then the phone doesn't function as advertised and is no longer a smart phone. It is unreliable and essentially useless as a business device. iPhone is advertised has having 10 hours talk time and 10 hours cellular data. It doesn't even come close. I encourage everyone to contact Apple directly to address this problem. Something tells me Steve Jobs never would have let this happen.Â