Iphone 5 battery acting weird. what to do?

[bhigh8]

So i have a replacement Iphone 5 thats is still under warranty and didnt know what to do. its been perfect for a month or two and this morning the battery drops to 86% after 3 minutes of use. so turned it off and back on. it drops two more percent. so i reboot it ( hold down home and sleep button). it starts dropping more. so i plugged it back in. its charging rather fast also. I dont know what to do.

Do i just use and run it down to 0%? do i reset it? do i plug into itunes?

also, is this a sign of a bad battery. i could get replaced or is it just a glitch and will go back to normal. I was getting between 7-9 hrs depending on what i was doing before.

Just really lost on what i should do.

 

[thenewone]

Try recalibrating your battery: Use your phone until it completely dies, then charge uninterrupted (and without using it at all if possible) until it is fully charged. Use your phone as normal and see if problem fixed.

If not, do a clean restore through iTunes, setting phone up as new. Repeat battery recalibration.

If still not fixed, take advantage of your warranty and get it replaced.