MBA battery life after installing OS X El Capitan

After downloading and installing OS X El Capitan (10.11.2) on my 2013 MBA battery life went from 10-12 hours on a full charge to 5 hours at most. Yesterday I restarted my computer and everything was back to normal and i was so happy. Then i saw another update for OS X El Capitan (10.11.3), downloaded it expecting good results and my battery life flew back down to 5-6 hours on a fulI charge. I dont know why but it obviously has something to do with the system update. I even fixed specific things so CPU usage on activity monitor is low for everything and it still doesn't make sense to me, any sugggestions?