I'm sure many of you on here have done this, but this quick fix can greatly help anyone who already doesn't know. My battery life was great before Jelly Bean, but lately it seems with little use it was dying in less than a day, overnight, etc. Upon checking battery stats, my Wi-Fi was solid blue. Apparently, the default setting for Wi-Fi is to stay on even when the tablet is sleeping. This makes no sense to me as I (and I assume most other users) have phones to handle everything when not using the Nexus tablet. I don't even have notification sounds active on my 7 because its redundant when I'll get them from my RAZR Maxx. So, unless you want your Nexus 7 to have constant Wi-Fi, you should go into Settings>Wi-Fi>Advanced and turn OFF Keep Wi-Fi On During Sleep. I've noticed no lag connecting to Wi-Fi when waking my tablet up and my battery life has tripled. Hope this helps someone not ecstatic with their battery life!