After some testing i have found that one of the principal causes of batery draining and slowing down your phone performance is due a process called ksoftirqd (usually PID: 3), but why this process sometimes begins to eat your CPU resources? all tests i've made are pointing to wlan driver, and i'm very convinced that this is the problem with this process. If you turn on/off wifi several times probably will appear this problem, if you let your wifi turned on conected to a wireless router through the night, or for long periods of time will appear this problem too.
This issue does not happen with frozenlake kernel v3, maybe because it has Wifi modules from Lukiqq
The kernels i have detect this issue (surely) are:
Voku's 1.7A (MT2.4 & Qbanin)
There are others kernels that will have this issue, test them on your own!