if you're getting less than 10 hours on the OEM battery, you have a bad battery and contact LG about it.
BUT at the same time, look at the power saver options, apply those permanently and disable power saver mode.
in easier terms, Turn off Auto Sync, Lower screen brightness to 10%, turn off GPS...etc etc etc. and then if you're getting less than 10 hours then contact LG about having a bad battery...
Battery Calibration Debunked (By Actual Google Android Dev)
http://forum.xda-developers.com/showthread.php?t=1443108