Why is my iphone 5 loosing so much battery?

So I have already had to get a new iphone 5 through my warranty for a broken battery and now this one is doing the same… I could leave the phone locked for 10 minutes and have all apps closed and I'll get back and atleast 10% battery would be gone when I use it again
How can I stop this from happening?

Added (1). No the phone has never even been anywhere near water not even near a drink

Did you wetted it somehow?
like left in the toilet while you are having a bath?

Too much tire tread

Sounds like your battery just went bad or you got a bad one, etc. Take it to an apple store to have them look at it, or they can also put a new one in.