Why does my iPhone 6 battery drain so fast?

I

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Cellphone issue

My iphone 6 battery drains so fast , I done everything with it like recovery, limiting setting (location etc) then i also replaced the battery with new one . But same problem occurs. Sometimes my cellphone hangs while using multiple apps but it happens rarely.
I almost tried everything but battery remain about 10 to 12 hours only ...
Need help !