A couple of mornings ago, I woke up to find I only had 6 percent battery life remaining (down from 66% when I went to bed). I went to settings to check battery usage.
Normally, screen usage counts for 98 percent of my battery use. That morning, facebook was using 40 percent of my battery power. I force closed facebook, but it continued to use 40 percent of my battery power.
The Facebook power drain was so intense, my nexus 7 was losing its battery power even while plugged in. Finally, I discovered an underlying sub program called katana which was using my resources. Katana polls location resources (GPS) constantly, and turned out to be the resource hog.
Once I closed facebook and katana,, and shut off location resources, facebook had still toggled something in the Android OS that was consuming 30 percent of my battery power. I uninstalled and reinstalled facebook and played around with different location resource settings until i got the android OS usage back to normal, and now the problem is solved,