When I first bought my 4s I was losing 2% overnight on standby.((At normal factory settings with cloud enabled!). There was a little bug causing my phone to miscalculate at 1% resulting in prolonged usage. The third day I had my phone I decided to drop some settings to prolong usage and things went downhill from there. My phone started draining 30% overnight in standby and about 1% per minute during light use. after dropping ALL settings- (location services, cloud, wifi, itunes ping, push notifications, etc.etc.etc) things have not gotten any better. I dont care what idea you can come up with- (Wifi search,diagnoistics, compass calibration, auto time set, stock ticker,iAds ) NOTHING made it normal again. The phone would get warm during standby as if something was running while the phone was off. What I beleive happens is something is getting stuck in a repeating error cycle causing the phone to drain the battery. Im 100% sure it is a software issue (I'm sure there ARE bad batteries out there too but for the most part you can probably fix your phone for the time being yourself.) Test it yourself Download a fresh install of IOS5 off of itunes. Then do a full restore ie factory reset of your phone. Set the phone up as new and do not allow apple diagnostics, skip cloud setup, allow siri, and allow location services. Do not change any other settings except battery %. Do not download any apps. Do not set up any email. Do not add contacts. With my phone in this state I have fixed the draining. As of right now Im at 21.5 hours standby 1 hour usage with 68% battery left. Prior to this fix I was getting 6 hours standby 1 hour usage for a full drain. Test it out for a day and see the difference. Then slowly start adding features until you notice the drain again. As for me im going to leave my phone as is to save my phone from excessive charge cycles until a fix is out. TL;DR Do a full restore from a fresh install of ios5 on itunes. Skip setting up cloud and dont mess with any settings. Test the phone out for a day without setting up email or downloading apps. Just test the standby and you'll notice its fine.