Ubuntu 18.04 battery life

This is how I get the best battery life with my Dell XPS 15 9570 (nvidia graphics) on any Ubuntu 18.04+ based system (Elementary OS, Mint, etc.)

Install packages:

sudo apt-get install tlp powertop

Enable tlp:

sudo tlp start

Check that it's running:

sudo tlp-stat -s

Check battery drain watts with AC disconnected and most apps and browser tabs closed (give it a few moments to stabilise):

sudo powertop

Press ESC to exit (it takes a few seconds).

---

Important for nvidia graphics

Using your onboard intel graphics when you're on battery should make a big difference. However tlp will not power down the nvidia card by default when using your onboard intel because it expects another service such as bumblebee to do so. Bumblebee doesn't work in Ubuntu 18.04+ so tlp is the best option.

sudo nano /etc/default/tlp

Uncomment this line and set value to empty:

RUNTIME_PM_DRIVER_BLACKLIST=""

Switch to your intel graphics, restart and check power usage:

sudo prime-select intel
sudo reboot
sudo powertop

Note in future switching to intel or nvidia only requires a logout depending on your setup.

---

Optional further steps (applicable to all machines)

Check if --auto-tune reduces your power significantly:

sudo powertop --auto-tune
sudo powertop

If --auto-tune made a big difference then go to the powertop tunables by pressing TAB a few times. Anything you adjust here is temporary. Test which ones make a difference in your power usage without causing any annoying behaviour such as sleeping external USB devices too quickly. Now make them permanent by editing tlp config. This requires some experimentation.

To edit tlp config and restart it afterwards:

sudo nano /etc/default/tlp
sudo systemctl restart tlp

Refresh powertop tunables page by pressing r.

There are multiple power managers, and for a laptop, you may want to use laptop-mode-tools:

sudo apt install laptop-mode-tools

Per linrunner, author of TLP:

"Conflicts: laptop-mode-tools" --> salsa.debian.org/MoonSweep-guest/tlp/blob/master/debian/control 

So installing laptop-mode-tools will remove tlp and vice versa. I would not recommend using apt purge because users will loose their edits to /etc/default/tlp (in case they want to reinstall tlp).

You can monitor/diagnose your power consumption with powertop:

sudo apt install powertop 

I'm willing to bet that your problem has to do with your nvidia graphics card running all the time, despite switching to intel graphics. That seems to be the problem for everyone running 18.04 Ubuntu and they still hasnt't fixed it...

More info:

• https://github.com/timrichardson/Prime-Ubuntu-18.04
• https://bugs.launchpad.net/ubuntu/+source/nvidia-prime/+bug/1765363