There's no such thing. The two biggest factors which determine battery life are phone setup & usage. If you're not on top of those two things, makes no difference what kernel or rom you run (rom has almost nothing to do with it).
The only way to get great battery life is to tweak, test & experiment. There are 'shortcuts'; there is a multitude of threads on here with suggestions you can try & see how they work for you.
But there's no magic way to achieve great battery life.
If it's important enough to cause you grief if it's lost, back it up. No excuses
Trolling for thanks is lame
Does Samsung's auto-brightness implementation crap drive you to self-harm ? A solution !
Failure to search is the leading cause of male impotence on XDA
If you don't know how to recover if things go wrong, what are you doing flashing custom roms ?