Here is an app that is recommended by a lot of users including myself. It is designed to enable you to adjust, modify, or just playing with your kernal to find the best battery life, speed, etc.
This App can be found in Play Store HERE
Below is the settings and options for different screens that I currently have on my device. I haven't done much but play with the min - max and the governor. With these settings I can run 15 or so hours without having to hit the charger.
You can also purchase the donation app that gives you a bit more flexibility with the free version.
Info.png Tool.png General.png Specific.png
You really can't hurt anything when using this app that I have been able to find anyway. Just play with it and see what it does would be my suggestion.