I've seen this happen a few times when I've done a fresh installation of iOS7. Last night I deleted the blob on my pc and downloaded a fresh copy of 7.1 through iTunes. Once completed I was getting decent battery life. However, as has happened before, when I switched my phone off at bedtime and restarted it this morning, it was draining MUCH quicker than it was yesterday evening. It seems that switching my phone on and off has caused 'something' to happen. Any ideas what this may be?