Most of the time when using my laptop I am plugged into it’s AC charger. But, I don’t want my lithium-ion battery charged to 100% all of the time, as that is unhealthy for the battery and will lead to it prematurely losing capacity.<\/p>\n
My Lenovo X1 Carbon allows you to set a value less than 100 in the:
\n\/sys\/class\/power_supply\/BAT0\/charge_control_end_threshold
\nfield and will stop charging your battery if it goes above that amount.<\/p>\n
So you can issue a command like the following to prevent your laptop from charging your battery above 80%:<\/p>\n
echo \"80\" | sudo tee \/sys\/class\/power_supply\/BAT0\/charge_control_end_threshold<\/pre>\n(and if you wanted to get fancy, you could tell it to not start charging the battery until it fell below 70% with a command like the following)<\/p>\n
echo \"70\" | sudo tee \/sys\/class\/power_supply\/BAT0\/charge_control_start_threshold\r\n<\/pre>\nThen, you would have to unplug the laptop to discharge the battery below 80, and it would just stay there. \u00a0 If you were planning on taking your laptop somewhere without a power cord, you would want to reset this to 100 and fully charge it before you left.<\/p>\n
On the X1 carbon with Ubuntu 21.04, I got some “\/sys\/class\/power_supply\/BAT0\/charge_control_end_threshold: Invalid argument” type errors when trying to set the end amount to a value lower than the current start amount (or the start amount to a value higher than the current end amount). So if you are messing with one, you should probably set the other appropriately before-hand. For example, I use the following commands, in this specific order to limit to 80 (start charging below 70):<\/p>\n
echo \"70\" | sudo tee \/sys\/class\/power_supply\/BAT0\/charge_control_start_threshold\r\necho \"80\" | sudo tee \/sys\/class\/power_supply\/BAT0\/charge_control_end_threshold\r\n<\/pre>\n<\/p>\n
And then to reset to 100 (start charging below 99 or less) I use the commands in this order:<\/p>\n
echo \"100\" | sudo tee \/sys\/class\/power_supply\/BAT0\/charge_control_end_threshold\r\necho \"99\" | sudo tee \/sys\/class\/power_supply\/BAT0\/charge_control_start_threshold\r\n<\/pre>\n<\/p>\n
Using this ordering prevents the Invalid argument errors for me.<\/p>\n
The above commands reset the default values, and will not survive a reboot. So if you want them to always be active, you can set up a system service which will fire every time your computer reboots by creating a file in \/etc\/systemd\/system\/ \u00a0 called charge-threshold.service that looks like the following:<\/p>\n
[Unit]\r\nDescription=Set the battery charge threshold\r\nAfter=multi-user.target\r\nStartLimitBurst=0\r\n\r\n[Service]\r\nType=oneshot\r\nRestart=on-failure\r\nExecStart=\/bin\/bash -c 'echo 70 | tee \/sys\/class\/power_supply\/BAT0\/charge_control_start_threshold; echo 80 | tee \/sys\/class\/power_supply\/BAT0\/charge_control_end_threshold'\r\n\r\n[Install]\r\nWantedBy=multi-user.target<\/pre>\nThen enable the service with the following:<\/p>\n
X1:\/etc\/systemd\/system$ sudo systemctl enable charge-threshold.service\r\nX1:\/etc\/systemd\/system$ sudo systemctl start charge-threshold.service\r\n<\/pre>\n","protected":false},"excerpt":{"rendered":"Most of the time when using my laptop I am plugged into it’s AC charger. But, I don’t want my lithium-ion battery charged to 100% all of the time, as that is unhealthy for the battery and will lead to … Continue reading