Guys, if you experience battery drain on you Lumias report it to Microsoft by posting Battery Saver screenshots using this thread
Battery draining faster after windowsphone 8.1 update
Here is a response from the Windows Phone Tech regarding the battery drain issue in WP 8.1
"Hello Everyone,
The first day after updating your device you can expect some battery consumption due to the reinstallation of all applications and normal restoration that may occur post update.
We ask that you watch your battery consumption on day 2 and 3 and do so through the Battery Saver application. If you can please open the Top 2-3 items in the battery saver application and look at each application you will see if the battery consumption is based on background task or if the application was active on the screen being used by you. If you see a large amount of consumption in the background compared to your own personal use as the application it would be helpful to watch those.
In addition, if you can please also go to Settings -> Email + Accounts and see if any accounts are stuck in sync mode. There could be an account sync issue that is occurring. You can stop the sync and re-add the account to see if it resolves your issue or if the primary account simply restart the phone.
If you continue to see the issue, please provide some screenshots of your battery saver application, and the second screen for the top 2-3 items so we can see consumption.
Thank you,
Eli A.
Windows Phone Support - Tech Lead"