My iphone 5 battery is draining fast?

My iphone battery is draining really fast i have every setting possible that could drain battery off i have my brightness on the absolute lowest possible and i have auto brightness off and it drains 1 percent every 2 mintutes and 1 percent every 8 to 10 minutes on standby whats going on?

Added (1). Oh i forgot to add that i only charge it when it is dead or at like 5 percent battery

You probably charged it too often. It's not good to charge your iphone before its 'red' too often. Why don't you try letting it die down all the way and without turning it on, charge it to 100% without touching it? If this works, make sure you do this at least once a month:)

hope i helped!

Maybe your charging it too much or something else is running and don't know it. Try doing some more things like turning off notifications or any apps that might be running. If nothing then go by the apple store and ask for help they might get you a new one depending if the waranty still exsist

Background apps running? It shouldn't drain at all once it goes dormant and not being used.