Ok. I also find that /sys/class/power_supply/AC/online does not exist in my
laptop and can't find modifiable variable for it.

But never mind. I now decide not to use battery information in mode line.

Thank you!

2017-02-21 11:52 GMT+09:00 Glenn Morris <rgm@gnu.org>:

> soulawaker wrote:
>
> > My laptop battery informations was placed in
> > /sys/class/power_supply/CMB0.
> > But battery.el try to find only /sys/class/power_supply/BAT% series.
>
> In the Emacs repo, you can customize the option battery-linux-sysfs-regexp
> to match whatever you need. This should appear in 26.1.
>
> See https://debbugs.gnu.org/23216
>