The battery is draining fast due to many reasons. First, you have to disable all the background apps. Then clear all the junk files and cache on phone memory. Then check the battery status again and manage the apps that you are using. customized devices have draining much power than the regular one. So resetting all the settings into normal would be good. but after all this kind of activities you still suffering the same problem the new battery you have bought not be a quiet genuine one. Replace it with a genuine one is the best solution.