Howto: Battery thresholds on Thinkpads (TLP/Buster)

[Hallvor]

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:

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# 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.

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# apt install tlp tlp-rdw tp-smapi-dkms acpi-call-dkms

Reboot.

Now we’ll look for the correct kernel module.

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# tlp-stat -b

Look for the module that says unsupported hardware:

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tp-smapi = inactive (unsupported hardware)
tpacpi-bat = inactive (unsupported hardware)

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

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# apt remove tp-smapi-dkms

OR

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# apt remove acpi-call-dkms

Configuration

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

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# 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:

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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:

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# 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:

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# tlp fullcharge BAT1

* Edit: 14.05.2020: The path for Sid is /etc/tlp.conf. See below.

Credits:
https://linrunner.de/en/tlp/docs/tlp-li ... ement.html
https://linrunner.de/en/tlp/docs/tlp-configuration.html

[otas.pe]

On my Thinkpad T540p there is tp-smapi module inactive because not supported. It is OK or anything wrong?

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# tlp-stat -b
--- TLP 1.3.1 --------------------------------------------

+++ Battery Features: Charge Thresholds and Recalibrate
natacpi    = active (data, thresholds)
tpacpi-bat = active (recalibrate)
tp-smapi   = inactive (ThinkPad not supported)

[Hallvor]

It looks fine. The correct module is loaded. Just remove tp-smapi.

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# apt remove tp-smapi-dkms

[otas.pe]

OK, thanks. Only small correction, in Sid the config file path is /etc/tlp.conf not /etc/default/tlp. Any tips how to change config file?

[Hallvor]

Do you have config files on both paths?

[otas.pe]

No, only on /etc/tlp.conf

[Hallvor]

I may be thick here, because I can't understand what the problem is. Are you asking how to change the path of the config file from /etc/tlp.conf to /etc/default/tlp?

[otas.pe]

No, in your procedure there is config file path /etc/default/tlp. But in Sid I could not find there because location is /etc/tlp.conf

[Hallvor]

Yes, I saw that. I'll make the appropriate edit in the OP. Thanks!