[Galaxy Note II Q&A, Help & Troubleshooting] terzisc:
Alright folks, I think I have finally managed to solve the battery drain problem after the 4.3 update, thank God!

The bad news is that it cannot be done without your phone being rooted. So root the phone in the following manner: 1) Install "Kingo Android Root" to you PC. It will not root your phone without following the other steps.

2) Install "System App Remover" (the one by Jumobile) from play store. The app will be installed as a different name, as "Uninstall". I tried "All-in-One Toolbox" too but it coudn't find all the files listed below (namely KLMS Agent). So I had to install this one and try again.

2.1) Install "Root Checker Basic" from play store.

3) Go to Menu>Settings>More>App Manager>All and force stop the apps:

com.sec.enterprise.knox.attestation

com.sec.knox.eventsmanager

Security policy updates

KNOX

KNOX -- (Yes we have two of them! One is to install Knox interface other one is the one that is already running without installing the other one.)

Knox Notification Manager

KNOX Store

KLMS Agent

In total we have 8 files (or actually apps) to close. You may have 7 of them if you don't have Security Principle Update.

Some of these will not gonna allow you to force stop, never mind, just close the ones that you can.

4) (Now you have to be quick because somehow these apps restart themselves.) Connect your phone to your PC and run Kingo and click root then follow the instructions on your pc screen. Your note 2 will restart and will be rooted.

5) Disconnect your phone.

6) Run "Root Checker Basic" and click "verify root access" and see if you are rooted now. (You should be rooted.)

7) Install "SuperSU" from play store.

8) Run "uninstall" (which we obtain by installing "System App Remover" (the one by Jumobile)). SuperSU will ask for root permission for uninstall, approve it. Uninstall will provide you a list, choose all the apps listed above and uninstall them. KLMS Agent will not be in the list and you should use the search option of the app. If for any reason you don't see any other app in the list search and uninstall! YOU SHOULD DELETE ALL 8 FILES!

9) Restart your phone.

After you remove all the Knox bloatware and anything else you don't like, install Lucky Patcher.

This is usually used to remove licenses from pirated apps, But it also does something else which we will need to use:

It removes Google ads! And these are that keep our phones awake.

In the faulty 4.3 Samsung update apps with Google Ads always try to connect and sync thus keeping the phone awake.

In Lucky Patcher go into each app individually and choose "Remove Google ads".

Then choose "Patch to remove Google ads" and press "Apply". Rarely will you have 100% success but it doesn't matter.

Then repeat the process and this time press "Disable Ads Activities" and press each activity that is used for advertising (They are usually in orange colour).

One more useful step is to use Greenify to hibernate almost all processes except the ones that need to sync eg Dropbox.

My phone used to have 65-85 % wake time after the update. Now it's only 3% wakelock instead of the 65-85% that was before and the battery only went down to 98% from 100% in 2.5 hours! Battery life is even better than on 4.1.2.

If for some reason after a few days (or even hours) the problem returns, then it could well be an app that causes it, or a combination of apps. In my case it was Automatic Call Recorder by App.liqato (Appstar Solutions). an app that was working fine on 4.1.2 but not on 4.3. It was the last app to be installed, that's why I knew. I uninstalled it and batery life is back to normal after it had gone mad for a couple of hours. Notice that no wakelock app showed it as the culprit. I only knew because after I had done a factory reset I installed all my apps one by one and not from a backup and I forgot this one. I remembered a few days later and when I installed it the drain started.