I went through this with my s3 a few weeks ago, even with Wifi and mobile data turned off I was losing 40% battery at night. Do you have chrome installed? There is a bug in that which drains battery, you can fix it by going to chrome settings/developer options and turning off tilt to scroll. I also used better battery stats and found out that a lot of my Wakelocks in standby were to do with mobile data, something to do with a system that Vodafone doesn't support so the phone is constantly requesting something from the network. Try turning off mobile data and see if that's the problem. Once I fixed chrome and turn off mobile data when the screen is off then I get 3% drain overnight!