wmbattery (laptop battery status dockapp)

wmbattery displays the status of your laptop's battery in a small
icon. This includes if it is plugged in, if the battery is charging,
how many minutes of battery life remain, battery life remaining (with
both a percentage and a graph), and battery status (high - green, low -
yellow, or critical - red).

Note: For wmbattery to work, the system message bus (aka D-Bus) must
be running. By default, this is enabled in the Slackware installer.
If you disabled it, you can re-enable with:

# chmod +x /etc/rc.d/rc.messagebus
# /etc/rc.d/rc.messagebus start