I just flashed the CM 12.1 Nightly and the AK Kernel. And after that I found a STRANGE SITUATION.
Usually, before sleep, I would turn my phone into Airplane Mode and just sleep. But I found the battery will reduce from approx. 100% to 92% in 5hrs.
How ever, during daytime with LTE signal, the battery seems not to drop.

Here's the battery history.
ww1.sinaimg.cn/large/49977c5dgw1es9g4ztzh8j20u01hcq7j.jpg
(Sorry I don't have the permission to put a direct link.)