[SOLVED] Power Management - Advanced Settings - Charge Limit

[FFDA]

Hi!

The KDE is forcing 50% limit everytime I reboot the or simply close the System Settings dashboard. I tried to set at 80% (for example) and, as soon as I leave the System Settings it forces 50%. I appreciate any help to help me with the fix OR to disable the charge limit.

Thanks,

FFDA

[doktor5000]

Hi there and Happy New Year,
it might help if you could add some context information on what you actually want to achieve, and also some information about your box make/model and what Mageia release you're using currently.

[FFDA]

Hi! Happy New Year!

There are two settings there: i) stop charging at and ii) start charging only once below. I wanted to stop charging at 85% and start charging at 15%... this is an interesting range to extend battery life, however after setting the limits my laptop keeps "73%, not charging" steady. Besides that, leaving the system settings or reboot the computer will force 50% as the limit for "stop charging at". At this stage, I do not mind to disable these settings and keep my battery always charging until it reaches 100%.

I am using the last version of Mageia in a Lenovo X390 Yoga.

Best!

[morgano]

Not entirely correct.

I had technicians from Varta coming to my lab for private education as i started using LiIon cells early, 1990 something. Some basics still stands today, and is common for many chemistries - the the amplitude hurts the batteries especially voltage amplitude, and voltage change raplidly at both ends of charge level.
So yes you should avoid charging too high.
But more importantly you should avoid to discharge too low, and to avoid that you should means you should make sure to have the battery charged. So start charging any time it drops below 85, stop at 85 is better. That both lowers amplitude and avoids lower voltage.

Also, deep discharge is worse than top charging, so if you plan to use much of capacity it is good to top it up as a countermeasure before.

Hard to tell exactly what is best because of different chemistries and also what do the system mean by 0% - is that at a level that is starting to really hurt the battery, such as 2,5V for LiIon where battery built in protection shuld kick in, or is it more like 3,2 V recommended lowest voltage (but still some percent left that *could* be used for emergency.

And to complicate things even more, most battery pack use cell balancers that only kick to work at close to 100 charge. How do we know how a specific battery pack works.
I even have repaired cell packs for hand tools from "high end" manufacturers, that did not contain *any* cell balancing. Then a cheap chinese had cell balancing (but low quality cells). Another had both issues correct but failed build quality. How hard can it be to produce serious equipment? Have found none yet.

- It is complicated, especially when details are unknown

I often dissasemble stuff and scrutinise it before putting in my customers machines...

[FFDA]

Thanks for the explanation! This is not my area of expertise but I got most of it. I have set both parameters at 85% and is currently working, meaning the system is no longer forcing the 50%... maybe this is a construct to avoid the amplitude.

I concur that there are unknown details here but leaving both at 85% seems prudent. Thanks so much!

[doktor5000]

This is not my area of expertise

Food for thought: why change those settings at all and not rely on the manufacturer defaults ?
Did you check whether your hardware supports setting this at all and also actually uses it ?

On a related note, there's an open upstream bug because it resets to 100% on every reboot, which is caused by hardware rewriting this
which also contains some context information on the topic: https://bugs.kde.org/show_bug.cgi?id=450551
As a workaround you could take a look at something like https://github.com/tshakalekholoane/bat

[FFDA]

Good points! ... the hardware is actually using it and the reboot is NOT resetting to 100%. I will have a practical approach... I will stay with 85% and check behavior and battery health... otherwise I will go back to 100%. Thanks again for the prompt reply and the links!

[pmr]

Maybe it is somehow related to the bug in the ideapad_laptop module, mentioned in e.g. this thread:
https://forums.mageia.org/en/viewtopic.php?f=7&t=15340

I personally have deployed a temporary workaround - blacklisting of this module, which, however has removed a bit of energy management-related functionality.

The bug has been corrected in kernel 6.16 and I am eagerly awaiting for including of 6.16+ kernel into packages for Mageia 9; the workaround had to be a temporary only but is being used for over one year now.
On the other hand - "never touch a running system" ;->

[Germ]

kernel 6.18.3 and 6.18.2 are in /backports_testing for Mageia 9. I'm currently using 6.18.3 and have had no problems.

[morgano]

https://wiki.mageia.org/en/Kernel_flavo ... rt_kernels