iphone 5 battery draining too quickly
The battery in my iPhone 5 is draining way too quickly, even though the battery was supposed to have been replaced just yesterday. Since yesterday, the power is down to 73% from 98%. The phone is on airplane mode, screen very low brightness, no sim card. I have't used it at all, since I have an iPhone 6 now.
What could be wrong with my phone?
MacBook Pro, OS X Mavericks (10.9.1)