Display the current (dis)charge rate
In the device list of the power manager one can get the details of a laptop battery. It is possible to see the current charge, the voltage abd full charge. It would be very useful to have there also the current rate at which the battery is (dis)charging. In other words, the output of this command:
upower -i /org/freedesktop/UPower/devices/battery_BAT0 | grep energy-rate
Even better would be that the value changes dynamically. That way one can have xfce4-power-manager open, lower the screen brightness or any other kind of tests and measure the immediate effect on the battery.