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How to drastically reduce your notebook energy consumption

 

One of the experiments I’ve done lately was to improve the battery duration of
my Dell XPS 15, since it was lasting only 3 hours.

Measuring it right

There are several apps to monitor how much energy your system is consuming, but
I ended up with powertop (more on that below).
Additionally, it’s nice to have a htop to see how your RAM/CPU/Process list is behaving
and find any processes that are memory hogging or that could be stopped at that moment.

Close/pause background services you aren’t using

I had a lot of background services that I wasn’t using all day long and
that were really fast to turn on again in case they were required.
Some examples:

Bluetooth:
I never use this so I completely disabled it on boot
Add rfkill block bluetooth to your /etc/rc.local.

Docker containers
You can kill all the containers you aren’t using, since you can always docker start later.
To kill all the currently running containers, try some bash-fu:
docker rm $(docker ps -q)

Virtualbox

I have a Windows SQL Server 2008 VM, which was using massive amounts of RAM, even more than
the limit I imposed to it!.

Fortunately, there’s a way to suspend and resume the VM, consuming virtually zero resources.
Right click over the VM, then Close -> Save State.
Next time you open the VM, it will come back exactly from where it was.

Chrome loves your RAM

With just 5 tabs opened and only 2 extensions loaded, Chrome was using an aberrating
1850 mB.
The same goes for any Chrome-based app (Unfortunately, Slack Linux App counts too)
so If I’m not using it (such as when coding), I normally try to close it.
Note that it also continues to run in the background so try a killall google-chrome
or kill it via htop.
Alternatively one could use firefox or any other replacement browser.. or open fewer
tabs.

Powertop optimizations

You can also open the powertop Tunables screen and activate/deactivate any tunable
entries and see how that impacts in your performance/battery life.
Once you find the right combination remember to save it and execute it on boot
following this article.

100% NERD mode

In this mode, the computer uses as few resources as it can. Some ideas:

  • Turn off all radio devices (WiFi/Bluetooth)
  • Lower monitor brightness
  • Set monitor sleep time to 10 seconds
  • Disable your graphic cards (Review Bumblebee on how to do this)
  • Boot in text-mode only (remember to configure it properly before!)

Remove powerclamp driver

This was making the notebook turn on the fans earlier than what it needed, thus making
a lot of noise. It also seemed that i had all the core processors at 50% even when doing
nothing.
To remove it I’ve added a new file /etc/modprobe.d/custom.conf with contents:
blacklist intel_powerclamp

Now

With WiFi: 5 hours 45 minutes @ 13.1 W
In NERD mode: ~7 hours