Howto: Battery thresholds on Thinkpads (TLP)

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Howto: Battery thresholds on Thinkpads (TLP)

Postby Hallvor » 2019-02-21 10:59

What is a battery threshold?

A battery threshold will stop the computer from charging the battery once it reaches a certain level and increase the lifespan of your battery.


Disclaimer


The following will/should only work on most IBM/Lenovo Thinkpads. If you have any other IBM or Lenovo laptops, this will not work.

OK, let’s do this

In this howto, we’ll use TLP. It will give you optimized power saving out of the box. If you already have laptop-mode-tools installed, you must uninstall it:
Code: Select all
# apt remove laptop-mode-tools


Then we’ll install TLP and the required firmware. Most Thinkpads will only need one module. Newer Thinkpads will generally only need the acpi-call package, while older models will need tp-smapi-dkms. We’ll install both of them and then find the correct kernel module later.

Code: Select all
# apt install tlp tlp-rdw tp-smapi-dkms acpi-call-dkms


Reboot.

Now we’ll look for the correct kernel module.

Code: Select all
# tlp-stat -b


Look for the module that says unsupported hardware:

Code: Select all
tp-smapi = inactive (unsupported hardware)
tpacpi-bat = inactive (unsupported hardware)


Then just delete the module (tpacpi-bat is acpi-call):

Code: Select all
# apt remove tp-smapi-dkms


OR

Code: Select all
# apt remove acpi-call-dkms



Configuration


All tlp settings are stored in /etc/default/tlp. Let’s edit it:

Code: Select all
# nano /etc/default/tlp


Look for the following lines. Thinkpads usually have two batteries, one internal and one external. BAT0 is the internal battery, and BAT1 is the external battery:

Code: Select all
START_CHARGE_THRESH_BAT0=75
STOP_CHARGE_THRESH_BAT0=80

START_CHARGE_THRESH_BAT1=75
STOP_CHARGE_THRESH_BAT1=80


These settings are fine if you use your computer on battery power a lot. Even if your computer is connected to AC power, it will not charge until the battery level drops to 75%, and will not charge above 80%.

If your computer almost always is connected to AC power, I recommend setting the charge threshold closer to 50% to maximize battery life.


Getting a full charge

Even if you have set the threshold to 80%, or even 50%, sometimes you just need a full charge. You can achieve this by entering the following:

Code: Select all
# tlp fullcharge


After a full charge, the computer will start respecting the charge thresholds again.

You can also charge just one of the batteries, for example:

Code: Select all
# tlp fullcharge BAT1



Credits:
https://linrunner.de/en/tlp/docs/tlp-li ... ement.html
https://linrunner.de/en/tlp/docs/tlp-configuration.html
Lenovo Thinkpad T440S, Intel Core i7-4600U CPU @ 2.10GHz, 8 GB RAM, 256 GB SSD, Debian Stretch (KDE)
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Hallvor
 
Posts: 874
Joined: 2009-04-16 18:35
Location: Norway

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