I read a Forum Discussion stated that Android OS' is killing the battery of the Nexus 7. This is a common issue with the Latest Android Os Version , the KitKat. Most of the discussions i have heard are people who had upgrade their OS system which is consuming a lot of power.
Fix Android 4.4.2 KitKat battery drain
I'll show you 3 Solution to "Battery drains faster after Android 4.4.update."
1 Stop Automatic Syncing(KitKat 4.4.2)
Navigate to menu>settings>accounts
2 Disable Google Auto-Voice Detection(KitKat 4.4.2)
3 Battery Saver Apps to solve battery drain KikKat
Download One of these apps. These are the best and the most voted Battery Saver app to extend your battery life. Most effective with the Moto X, Nexus,4,5,7 and Samsung Galaxy's
These are all Special Tips to Preserve you battery life with the new Andriod Kikkat 4.4.2