Persistent Battery Thresholds with Systemd

Here is the step-by-step process to make your battery charge thresholds persistent across reboots on Linux. This is useful for extending the lifespan of your battery by preventing it from charging to 100% constantly.

Step 1: Create the Service File

In your terminal, run the following command to create a new systemd service file:

sudo nano /etc/systemd/system/battery-threshold.service

This opens a text editor. You should see a blank file.

Step 2: Paste the Service Configuration

Copy and paste this entire block into the editor. This configuration sets the start threshold to 70% and the stop threshold to 80%.

[Unit] Description=Set battery charge thresholds After=default.target [Service] Type=oneshot ExecStart=/bin/bash -c 'echo 70 > /sys/class/power_supply/BAT0/charge_control_start_threshold && echo 80 > /sys/class/power_supply/BAT0/charge_control_end_threshold' RemainAfterExit=yes [Install] WantedBy=default.target

Step 3: Save and Exit

Press Ctrl + O (the letter O), then press Enter to confirm the filename, then press Ctrl + X to exit nano. You should be back at your terminal prompt.

Step 4: Enable the Service

Run this command to enable it to start automatically on boot:

sudo systemctl enable battery-threshold.service

Step 5: Start the Service Now

Run this to activate the thresholds immediately (without rebooting):

sudo systemctl start battery-threshold.service

Step 6: Verify It's Running

Check that everything worked:

sudo systemctl status battery-threshold.service

You should see output saying it's active (exited) or enabled.

Also verify the thresholds are set by reading the system files:

cat /sys/class/power_supply/BAT0/charge_control_start_threshold cat /sys/class/power_supply/BAT0/charge_control_end_threshold

Both should return your set values (70 and 80).

That's It!

Your battery will now cap at 80% and start charging at 70% automatically every time you boot your laptop. You're all set.