Battery suddenly draining a lot with El Capitan

[TechGod]

I changed literally no settings on my late 2013 rMBP and the battery is draining so fast all of a sudden.

 

[simonsi]

Well you could look in the activity monitor and actually see, either CPU or Energy tab should show you what is going on. Just sayin...

 

[Max(IT)]

I don't really have comparison available, since I immediately clean installed El Capitan over Yosemite in my brand new MBP 13", but I can say the battery life is amazing.
I can easily pass the 10 hrs limit with light usage (web browsing and mail).
I can't see how it could be better

 

[3568358]

I changed literally no settings on my late 2013 rMBP and the battery is draining so fast all of a sudden.

Check activity monitor. Make sure nothing is using more than a gig under 'memory' when you have no other apps open or running. Check the battery page as well and see the energy usage on apps.