second day of iphone 5 and it's at 49% after it been off charge for 3 and half hours. normal? or no?

kay so I got an iphone 5 two days ago and the battery isnt going to well, battery brightness is turned all the way down , i close my apps when i'm finished and i lock my phone when im not playing on it. But I finished charging my phone at about 530. it's 9 now and at 49%. My friend said he had the same problem when he first got his iPhone 5 and it "adapts" to you in a bit and the battery gets stronger . But , is this normal? and how do I make my battery last longer ? because I've heard it supposed to be more lasting