My iPhone 6s battery its lasting very long my 5c lasts longer than this one. I got it on 25th September from o2.

WWhy is my iphone 5c lasting longer on battery than my iPhone 6s. This shouldn't be the case. It gets very warm on charger as well. And also when your using it on Facebook. On the apple show it said that the iPhone 6s would last a lot longer than the older ones. Well it's not. And there's a lot of battery difference. My 5c lasts a lot longer than my 6s. This shouldn't be right. I got it from o2 on 25th September. I don't know what to do. I'm very disappointed.