Mouse battery status

I do not think mate-power-statistics or upower is working.

Mouse is a Logitech M325.

I have tried 3 different batteries and they all show 55%.

One AA battery and two NiMh batteries.

What is wrong?

Now that you mention it, I've just looked at mine. I have a logitech mx keys mouse and keyboard currently connected via a shared dongle. The mouse is apparently at 55% and the keyboard at 50%.

I have just had to plug in the keyboard as my work's Windoze PC has just told me it's low on juice.

The Windoze machine reckons that the mouse is 100% but I doubt that this is correct either.

Connected to Windoze via Bluetooth. Don't know if this is a logitech dongle thing.

Thanks for the feedback. I found this.

Laptops use a coulomb counter. Because they in effect, measure "fuel",
the percentage figure is relatively trustworthy.

But other devices use a simple voltage measurement, then
consult an open circuit voltage versus time table, to
guess at how much of the battery is left. This is
fraught with error.

In your case, the Logitech does not know the cell chemistry.
Consequently, it cannot "pop the correct table" into the
math. It has probably assumed alkaline chemistry for all
three readings, causing a fully charged LiMh to read
lower than it should.