Battery charge threshold: BIOS vs OS

Framework Laptop 13 Linux
8

Variation on the theme above for those that may want to use bios and the framework_tool for battery charge control. Note that using the framework_tool requires having kernel 6.12 or higher.

This and other topics caution against using the bios charge control feature and/or the framework_tool when using /sys/class/power_supply/BAT1/charge_control_end_threshold to control the battery charge limit.

While I think using the cros_charge_control kernel module parameter charge_control_end_threshold and the systemd unit described above is (more) straight forward, I prefer to use the bios and the framework_tool.

The recent beta bios updates (for both intel e.g. here and ryzen e.g. here) that include the new “automatic battery lifetime extender” feature further push me to use the framework_tool (i.e. is this new bios feature also incompatible with the charge_control_end_threshold parameter method?).

A bash function included in ~/.bashrc and a systemd unit:

batcc() {
    # installation:
    # cd ${HOME}
    # git clone https://github.com/FrameworkComputer/framework-system.git
    # cd framework-system
    # cargo clean
    # cargo clippy
    # cargo fmt --check
    # cargo fmt
    # cargo build
    # sudo cp target/debug/framework_tool /usr/local/bin
    # sudo cp ${HOME}/batcc@.service /etc/systemd/system/
    # sudo systemctl daemon-reload                                                        
    # sudo systemctl enable batcc@60
    # sudo systemctl start batcc@60
    # sudo systemctl status batcc@60
    # sudo journalctl -xeu batcc@60.service
    lower_limit=40
    upper_limit=100
    batcc_status="/usr/bin/sudo /usr/local/bin/framework_tool --charge-limit"
    batcc_usage="usage: batcc <percent>; ${lower_limit} <= <percent> <= ${upper_limit}"
    if [ -z "${1}" ]; then
        echo "${batcc_usage}"
        $batcc_status
        return 1
    else
        limit="${1}"
    fi

    if [ "${limit}" -ge "${lower_limit}" -a "${limit}" -le "${upper_limit}" ]; then       
        /usr/bin/sudo systemctl restart batcc@${limit} 
        $batcc_status
    else
        echo "${batcc_usage}"
        return 1
    fi
} # END batcc

batcc@.service:

[Unit]
Description=Set a maximum percent charge limit via framework_tool

[Service]
Type=oneshot
ExecStart=/bin/sh -c '/usr/local/bin/framework_tool --charge-limit %I'
RemainAfterExit=yes

[Install]
WantedBy=multi-user.target

The above has been working for me with kubuntu 24.04 lts and a 6.14 kernel.