pkg-descr

'asapm' is an X11 client which displays a battery status of your
notebook computer equiped with APM (Advanced Power Management) BIOS.
The status displayed consists remaining battery life, an AC line
status, a charging status and a digital readout with (a) Percent
battery remaining and (b) estimated time to dead.

NOTE: You need APM driver in your kernel. And enable it to edit
file /etc/rc.conf at `apm_enable=NO' to `YES'.

WWW: http://www.tigr.net/afterstep/view.php?applet=asapm/data