I updated to Lolipop now I can watch the battery percentage drop. I have tried factory resetting twice and same issue...well typing this message the battery has dropped 5 percent. Needs addressed as soon as possible. Phone is now unreliable. Seems slightly better in safe mode. Issue only happens with screen on on idle or sleep its fine....android battery section says it's the android kernel using all the power. This sucks. Want 4.4.4 back at least it was usable.
There are sites on line that tell you how to restore to kit. Kat 4.4.4
Here is one i found for the nexus.
How to Downgrade Android 5.0 to Android 4.4
Written by Josh Smith
Hope it helps.
I fact reset again and then disabled about 60 apps to see if it would help.
It's better but still worse than 4.4.4. Trying to kill the phone now and
recharge to test to see if it helped.
I did allow my battery to drain until the orange indicator showed at the bottom of the battery meter. It did not seem to change the performance. Just sitting on top of my cubicle at work today, the battery went from 94% to 68% in 8 hours. that is just standby drain.
I stabilized my phone's battery problem by turning off GPS. With this on, the notification panel shows 'Searching using GPS..." on an interval of each 3 to 4 seconds. That looked a little suspicious and gave me the idea to try turning GPS off as an experiment.
I don't know if battery life is back to normal or not but it is much better. of course, now the phone has lost the feature of GPS. Obviously this is not a long-term solution.