A script that writes into the EC in order to stop charging the battery at a specific threshold, requires https://github.com/hirschmann/nbfc ec_probe script

hp-15s-battery-charge-stop

#!/usr/bin/env bash
THRESHOLD=70

setup() {
    mount -t debugfs none /sys/kernel/debug
    tlp ac
    sv stop tlp acpid
    echo high >/sys/class/drm/card0/device/power_dpm_force_performance_level
    echo performance | tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor
}

cleanup() {
    echo auto >/sys/class/drm/card0/device/power_dpm_force_performance_level
    echo ondemand | tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor
    sv start tlp acpid
    exit
}

trap cleanup SIGINT
setup

while true; do
    BATT_PERC=$(upower -i /org/freedesktop/UPower/devices/battery_BAT0 |\
        grep -oP "(?<=percentage:          )[0-9]*")

    if [[ $BATT_PERC -ge $THRESHOLD ]]; then
        ./ec_probe write 0x40 0x00
    fi
    sleep 2
done
cleanup