Created attachment 4768 Screenshot showing the problem On my laptop (asus z35fm), after running on battery power for a non certain amount of time, xfce4-power-manager suddenly starts reporting the battery as being very low (for example, 5% or so). Other programs such as xfce4-battery-plugin and "acpi -V" report the correct percentage.
Please retry with the current version 1.4.1 and reopen if the issue is still reproducible.