[Q] Battery life on stock roms? topic

So bought this phone brand new a week ago for £300, and i like it a hell of a lot, i've been eyeing it up for ages but didn't have the money to get it. It came with KitKat and i updated automatically to Lollipop, i've tried a custom stock rom and everythings fine but my battery life is not that good, i've seen people saying that KitKat was a lot better battery wise anybody experience this as i didn't really stay for my kitkat experience lol. Many thanks