Hi, my name is***** can help you.
Samsung S4 batteries are known for going bad, however, there are things you can do to extend the life of the battery.
These type of batteries have a charge memory, so you need to maximize there charge level. This can be achieved by proper charge cycling.
There are even apps to help guide you to proper charging cycles.
I strongly suggest download Juice Defender from the Google app store. Here is the link:
Also, many people tend to keep their phone plug in and charging much of the day. This is bad! If you charge the battery too much, you are causing the battery memory problem I spoke of. The best way to keep your battery healthy is to charge it to 100%, then use it until it is completely drained. Charge it again and completely drain it again. Do this regularly and the batteries memory will be at close to zero, allowing it to hold a charge longer, and charge to 100% from zero.
The original talk time for this model was tested at 13 hours talk time for a new, fully charged battery.