It is no secret the battery life on the Nexus is pretty awful. Even with the extended battery we can only hope to get a good 5 hours or so at a time. That being said I've got an interesting story to share that happened over the last few days... My battery life had always been awful, even the extended battery only helped marginally. I am rooted of course with a nice undervolted kernel as well. The other day my USB port started acting temperamental and wouldn't always charge the phone without some fiddling. The next day it failed altogether. Frustrated, I took the phone apart to assess the damage, and found the port had melted into itself. No biggie easy repair, I'll buy a spare battery and wall charge till the internal flex port replacement arrives ( only $8.95 BTW). In the meantime I removed the melted port. Funny thing is, since then my battery life has been great. I think the way it had melted had kept it in a state of always thinking it was plugged in. So if your nexus battery life has degraded substantially over time do yourself a favor and check the USB port. The USB on these phones are flimsy as it and lots of repair stories exist, but it may just be the reason your phone is losing battery at a horrifying rate. I know this may be a niche problem, but I hope this helps someone in the long run.