Turn off Wireless Connections
Here’s another simple option that can help your battery survive in an emergency. Remember that having your Wi-Fi, Bluetooth, or your cellular data on when you’re not using them is a waste of battery life you can easily avoid.
If you’re not using a Wi-Fi connection, turn off your connection and vice-versa. The same goes for AirDrop and Bluetooth when you’re not using them.
If you really need to save battery, you can turn on Airplane mode. For MacBooks, it’s a bit trickier though, since they don’t have Airplane mode, so you’ll have to turn off all connections for yourself.