Here are some Tips to get the most out of the battery in your Macbook. First things first, screen brightness. If you don't use your screen, why have it on, right? You can decrease screen brightness on your Macbook by pressing FN F1 and increase by pressing FN F2. Note: you might not need to use the FN key depending on if you have "Use all F1, F2, etc. keys as standard function keys" checked or unchecked in system preferences/keyboard which is found under the keyboard tab. Turning the screen brightness all the way down to 0% completely turns off the display. Keep in mind, sighted people won't be able to see anything on the screen. When you restart your Mac, Screen brightness will default back to 100% if screen brightness was set to 0% before shutdown. Make sure to lower it again upon restart.
Another thing we can do to squeeze a few more precious minutes out of our Macbook batteries is to fiddle with keyboard illumination. First, go into system Preferences/ Keyboard, and select the keyboard tab. Now, uncheck Adjust keyboard brightness in low light. After that, press FN+ F5 to lower keyboard illumination. Press FN F6 to increase.
Another thing you can do is turn off the infra red receiver on your Macbook for remote controls if you don't use it. To disable this, open system Preferences and go to Security & Privacy, and select the general tab. You will need to navigate to the lock, Press control option spacebar, and type in your password to gain access to the settings. Now, press the advanced button. In this window, navigate to Disable remote control infrared receiver and check it and press enter. Your all set.
There are a few other things you can turn off like bluetooth for example if you don't plan on using it. Hopefully, some of these tips will help you squeeze a little more battery life out of your Macbook.