Battery %emptytime returns empty string

[riazufila]

When my laptop's battery is full, the %emptytime will return as an empty string. How do I make it return a custom text or symbol?

[riazufila]

This is my i3status output based on the following configurations.

battery all {
        format = "<span background='#458588'> %percentage %status (while != %emptytime) </span>"
        low_threshold = 30
        threshold_type = "percentage"
}

However, when the battery is full, %emptytime will return an empty string. So i3status output will appear as the following.

What I want to achieve is to be able to return a custom string for %emptytime when battery is full.