ASUS GL702ZC: How to limit battery charging?

I’m asking this question as I think it’s probably needed to prolong the laptop’s battery lifespan.

The laptop I’m using is already 3 years old and recently when I was upgrading stuffs I noticed the old battery has become badly swollen (it might have been swollen a long time ago just that I didn’t notice as I don’t open the laptop’s back cover too often), so I replaced it with another one.

But anyway, in order to further prolong the battery’s lifespan I’m considering about limiting the battery’s charge threshold, but this laptop is a bit different from others, that I couldn’t find the /sys/class/power_supply/BAT0/charge_control_end_threshold file that’s supposed to exist since 5.4 kernel.

Though for this laptop the battery is less relevant (lasts only for about an hour or two, with CPU clocks throttled to around 540MHz), it’s still useful to keep data safe in case of a power outage (so I have enough time to conclude the work and shut down, similar to a UPS).

Perhaps see:


I’ve already read about these.

It’s that the file in question is not present, and I tried echoing one through a root shell (sudo -i) but it does not work. I got a permission denied error.

EDIT: This is the only message about battery in dmesg.
[ 0.355650] battery: ACPI: Battery Slot [BAT0] (battery present)

Check the firmware settings to see if it has an option. Make sure you have the latest BIOS update as well.

EDIT: It looks like the feature may not be supported, but you could try what this person suggests:

Maybe I can take a look. I’m already on the latest 306 BIOS.

Guess my laptop is a special case that the setting is indeed not supported…