Battery draining fast problem

HEllo folks, I did buyed iPhone on 26dec last year, so means mine phone is old about month and half. My phone is draining battery so fast. I plug out from charger in morning and after 7h 15 min stand by and 1h usage i got 80% battery. In that 7h of stand by I have 3h with no network coverage no signal at all. I did call the apple they said me to restart mobile and test it 2-3 days without backup. Restarted it and its same. For example atm I have 52% with 10h 30min stand by and 3h usage. I will say again phone is restared only facebook and messanger. No emails no newspaper apps no anything. My brother got iphone about 6months and hims phone is giving better results than mine almost new phone. Is it normal? am looking on internet that peoples are using thems iphones for x2 days with 7-9 usage time but mine doesnt give that result