how to check what drains my 810?

[810newp]

My son gave me his Lumia 810 last month. I discovered it is not original battery but a 3rd party called mpj when I removed the back door yesterday. In spite of its good battery life (3-4 days easily), I still want to know what drains my phone most. Anyone tell me how to check what stuff drains my battery? Thank you.

 

[stmav]

The following thread has a lot of discussion and information on battery drain. You should be able to find what you are looking for there. Good luck.

http://forums.windowscentral.com/windows-phone-8/238706-do-you-have-random-battery-drain.html