If the new battery is also not lasting long I would first look at the charger and make sure it is actually putting out the right amount of charge. Next I would look at what you have running. Are there always apps running in the background? They will use up battery life even if you aren't actively using them. As long as they have not be closed they use battery. If you are watching movies, videos, or playing games that will also use up a battery quickly. Also every phone conversation uses a lot of battery.
Now that particular phone should have a good battery life. But if the battery you replaced it with is a cheaper aftermarket one, then that would not be as good.
Should all this not help, then you may want to have the device looked at.