Set Dell Battery Charge Limits on Linux with smbios-battery-ctl

Lithium-ion batteries degrade faster when they sit at 100%, especially if the laptop stays plugged in. On a Dell machine, the practical fix is a charge window: stop at 80%, resume only after it drops below 50%.

Dell’s smbios-battery-ctl writes those thresholds to the Embedded Controller (EC). Unlike a userspace daemon, the limit stays in effect across reboot, sleep, hibernation, and even while the machine is powered off and still on AC.

• Install smbios-utils
• Set the 50%–80% window
• Verify

Install smbios-utils

Ubuntu / Debian:

sudo apt install smbios-utils

Fedora / RHEL:

sudo dnf install libsmbios

Arch:

sudo pacman -S libsmbios

Set the 50%–80% window

Switch the charging profile to custom, then set the start and stop percentages:

sudo smbios-battery-ctl --set-charging-mode=custom
sudo smbios-battery-ctl --set-custom-charge-interval 50 80

Dell BIOS rules: start must be at least 50%, and stop must be at least 5% above start.

Verify

sudo smbios-battery-ctl --get-charging-cfg

Expected output:

Charging mode: custom
Charging interval: (50, 80)

If that interval shows up, the EC has the new limits. No extra service or reboot is required.