Battery Issue.
I have a 3 week year old macbook pro, and sometimes it says I have 7 hours left of battery life at maximum battery but sometimes it says I have 2 hours left all of a sudden. I have checked activity monitor multiple times and nothing appeared to be taking too much energy, and have also have attempted to wipe my computer. Can anyone help?
MacBook Pro with Retina display, OS X El Capitan (10.11)