When we ran a poll about battery life post the NoDo update about 15% of users complained of worse battery life.
While this may just be a psychological effect, WindowsPhoneMe may have just the cure, whether the effect is real or not.
They suggest a simple re-calibration of the built-in battery sensors by running the battery fully down, to automatic shut down, and then recharging from the mains (not the computer via USB) for 6 hours.
WPM suggests either running your phone down just using your normal routine and charging overnight, or using WP Bench, which has a battery run-down test built-in.
Read more at WPM here.