Anyway, as for all the smartphones in commerce, the battery suffers the multitasking and it needs to be frequently recharged. When you close an application on the iPhone using the home button the application still runs in background even if you don't need to use it. As a result your iPhone battery gets low very fast and you should to to recharge it frequently.
There is a simple tip that will help you to save your battery and use your iphone in a more efficient way. Press twice the home button. A pop up will show the applications running in background. If you keep pressing on one of them you will be able to kill the applications running in background.
With the help of this simple tip you will save lot of battery charge and will enjoy your iPhone without the stress to recharge it so frequently!