I have a Galaxy Note and updated to ICS about a month ago.... Like many of you I also experienced fast battery drain, around 10% or more per hour, without usage. even more when I use it. 5 hours with moderate usage. I am on unlimited data plan so 4G is always on. I also tried fully charging the phone before going to bed at 11pm, woke up at 6am and battery already at 20+%, that's when I was sleeping, no use at all. For a month, I have been charging my phone 2x a day! I was very frustrated and wanted to go back to GB. I was researching for weeks for the solution (also, checking for ICS updates almost everyday, waiting to see if Android had found a solution already), no one seemed to have a concrete solution, some suggest resetting, formatting etc. These were so complicated for me I didn't even dream of doing them. 3 days ago, I accidentally switched off my 4G connection. I didn't realize that the connection was off.. I was happy to see my battery charge was still at 98% after an hour, after 2 hours, light usage 95%. "What's happening?" Then I saw that my 4G was off. Now, I was thinking 4G connection was the culprit... but I wanted to explore more and see if there was an app that could be causing this.... I checked my apps that used data and nothing was on, then I checked my sync settings, This is where I found out that I had so many accounts that had SYNC ON! Twitter, facebook, gmail, samsung e-mail etc. So, I tried an experiment.... I stopped SYNCING everything. It worked! For one day, maybe 12hrs. (light usage with 4G connection on, just light usage, I checked my gmail by using the refresh button) 75% left on the battery!!! Wow!! Then I thought "come on...gmail and android? Same owner/company right? I'm going to try to turn ON the GMAIL SYNC, I'm sure there won't be a problem" I was right!!! Now on my second day with 4G connection ON, Sync Gmail ON, medium usage, maybe 20-30min of phone calls, 30 or more texts, email and around 10 minutes of internet surfing. 9 hours unplugged and battery only at 70%!!! I am very happy! Oh, last night, I think only about 8-10% of battery was used (6 or 7 hours of sleep only 8-10% used....) nice! For those who have not tried it yet... please try it... I hope it also works for you. I just wanted to share my experience and hopefully help others that are, i'm sure, also already so frustrated with ICS. I apologize for the long post. Cheers!