How do I get the battery status on the status bar?

I am running Ubuntu 16.04 on a new custom PC (Proteus series from PC Specialist). These computers are not tested on Linux, so I’m not expecting any support from them. Maybe you can help?

I have tried everything from this page: No battery status icon

I ran gsettings list-recursively|grep settings-daemon and got:
org.gnome.settings-daemon.plugins.power active true

After trying to check battery status from command line, as in here: How to check battery status using terminal? , I got:

username@boxname:~$ upower -i /org/freedesktop/UPower/devices/line_power_ACAD
native-path:          ACAD
power supply:         yes
updated:              Tue 25 Jul 2017 01:21:11 BST (74344 seconds ago)
has history:          no
has statistics:       no
line-power
warning-level:       none
online:              no
icon-name:          'ac-adapter-symbolic'

I thought maybe there are special drivers for batteries which Ubuntu needs to install, but it turns out I was wrong about that.

I’m at my wit’s end. Don’t really know what’s wrong, or what to do. Please let me know if you have any questions.