For laptop users who want to get better battery life, besides using a lightweight desktop environment, you can use power management tool called TLP.
TLP brings you the benefits of advanced power management for Linux without the need to understand every technical detail. TLP comes with a default configuration already optimized for battery life, so you may just install and forget it. Nevertheless TLP is highly customizable to fulfil your specific requirements.
How to Install TLP in Ubuntu:
1. TLP is available in Ubuntu universe repository. Simply open terminal (Ctrl+Alt+T) from application launcher.
2. Then run command to install the tool:
sudo apt install tlp
Type user password (no asterisks feedback) when it prompts and hit Enter.
For lazy men, you’re done as the tool comes with a default configuration already optimized for battery life.
Install graphical UI for TLP:
To fulfil your specific requirements, there’s a GTK user interface called TLPUI which makes it easy to change the configuration.
1. To install the tool, open terminal (Ctrl+Alt+T) and run command to add PPA:
sudo add-apt-repository ppa:linuxuprising/apps
Type user password (no visual feedback) when it asks and hit Enter to continue.
2. Then install TLPUI via command:
sudo apt install tlpui
3. (OPTIONAL) To remove the tool, run command:
sudo apt remove --autoremove tlpui
And go to Software & Updates -> Other Software to remove the PPA: