For some reason the battery life on my Note 2 seems to be much worse than what I remember.
I am struggling for 24 hours of life.
there are wakelock issues that have cropped up in the newest android build, it happened to me too - the wakelocks just suddenly start happening and the only way to kill the them are to power down, and pull the battery - but the problem eventually comes back.
The culprit is "mdm_hsic_pm0". It seems to be related to how strong your cellular signal is, the weaker it is the more this process will keep your phone awake. Some think its related to fast dormancy, which can be disabled (but you prob dont want to do that if your network supports it).
install a program like Better Battery Stats to see which processes are consuming the most energy. On a good day, i'll have around 2.8% consumption per hour with normal usage. On a bad day, it will be in the 6% - 7% range.
The problem is affecting me today too with that process having used 18.7% of my battery in about 2 hours of total awake time. There's a lot of chatter about it on various android forums, but no fix that I have been able to find.