Battery Notify

Update: TLP's battery care feature automatically starts and stops charging the battery for you. It supports LG Gram laptops as of v1.4. This renders battery-notify obsolete, as it was a stop-gap measure until a permanent solution appears.

Purpose

battery-notify displays a notification to remind the user to start or stop charging the laptop battery when its level goes below 50% or above 80%.

Context

To prolong battery life, it's best to keep it charged between 50%-80%. Keeping it completely full (or empty) stresses the battery, and degrades it faster. See this ArsTechnica article on the best way to use a lithium-ion battery, redux.

Most laptops with Windows preinstalled have an utility that can stop charging when the battery reaches 80% to extend the battery's life. This utility stops working if you dual boot into Linux.

Goals

Will do

• Remind the user to start or top charging the laptop when the battery level reaches predefined levels.
• Work with LG Gram 13 (model number 13Z980-U.AAW5U1; released in 2018) laptop running Ubuntu 18.04 or 20.04.

Won't do

• Automatically start/stop charging when the thresholds are reached.
• Work with other laptop brands/models.

Technical architecture

The current charge state and the battery level are read from the following two files:

• /sys/class/power_supply/ADP1/online
  • online is a text file that stores a value (0 - 2). It represents the state of power supply (VBUS):
    • 0: Unplugged
    • 1: Plugged in: Fixed Voltage Supply
    • 2: Plugged in: Programmable Voltage Supply
• /sys/class/power_supply/CMB0/capacity
  • capacity is a text file that stores a value (0 - 100). It represents the current battery charge level. On other systems, the battery stats may be listed under a BAT0 directory.

Reference: https://www.kernel.org/doc/Documentation/ABI/testing/sysfs-class-power

battery-notify reads the values from the two files and sends a notification using Ubuntu's notify-send utility. Message content depends on the charge state and the battery's level. battery-notify then goes to sleep for 5 minutes, and then repeat the above actions.

The requirements.txt file lists only black and mypy. They're used for linting during development. No external dependency is required for running battery-notify.

battery-notify installation and usage guide

1. git clone https://github.com/ericlingit/battery-notitfy.git
2. cd battery-notify/battery_notify
3. chmod +x battery-notify.sh
4. sudo cp battery_notify.py /usr/local/src
5. sudo cp battery-notify.sh /usr/local/bin/battery-notify
6. Add battery-notify to startup application settings (see screenshot)
7. Logout and log back in for the change to take effect