Facebook has announced that the battery issue is a big and an update will be provided -
"Hi folks, a number of you have commented on seeing a battery drain on your device since installing the new Facebook for Android app. We have identified the bug that is causing this battery drain and are working on a fix now. As soon as the patch is ready, we will push out an update. Thanks for the quick feedback and for your patience as we get this fixed!"
Taken from their facebook page -
http://www.facebook.com/#!/apps/appl...id=74769995908