When I first bought my phone, it had absolutely stellar battery life. I was able to get over 4 hours of screen time with %20 still remaining. Last Friday (4/18), I took the Verizon OTA update and everything seemed to go perfectly fine.
I am bone stock, s-on, no root...haven't even attempted the s-off.....yet.
Over the weekend I noticed horrible battery life. I was only able to achieve around 2 hours of screen time and even idle seemed to sap it much more quickly than before. I went through several reboots without a difference.
So, Monday night, I thought...hmmm...well fastboot still keeps some things hanging around in order to boot more quickly. So I went into the Power settings, unchecked the fastboot box, performed a power down, let it sit for 30 seconds, powered on and charged it over night.
Lo and behold, my original battery performance is back.
Best of luck.