1. Turn On the Battery Saver Mode
Every laptop is equipped with a battery saver mode or economy mode which puts the machine in a low power consumption state. The processor, memory, hard disk, etc. all start consuming less power by reducing their performance. This allows you to lengthen the time before the battery dies.
2. Reduce the Screen Brightness
As with any electronic device including your mobile phone, you should lower the brightness of your laptop’s screen. In fact, if the battery is about to die, lower it to the lowest setting. Most modern laptop screens consist of LEDs to provide the backlighting and hence, they do take up power.
3. Switch Off Unused Devices
Unless you are using them, turn off the Wi-Fi and Bluetooth because these are radio devices which consume quite a bit of battery power. Additionally, you can also turn off unused peripherals like a high performance graphic card (you obviously won’t need it to make a presentation), one or more USB ports (most laptops contain two to three ports, so you can turn off one),