Can i keep track of how much backround apps use battery life?

[UserMango]

I have Android 7.1. Do i need any third party app to do this or can i do this from the system?

 

[B. Diddy]

The system settings Battery menu ought to show you a breakdown of how much battery apps are using, regardless of whether they're in the foreground or background. The system menu usually doesn't show much detail, though -- for that, try a 3rd party app like GSam Battery Monitor.