What is the charging time or the charge status display of the battery in the Mini2 based on?

I charge a battery that is in the Mini 2 - according to the manual, the charging process is in progress as long as the LED on the front of the drone "breathes". As soon as this lights up constantly, the charging process is complete and the battery is charged to 100%.

But now the battery is 80% charged - after about 2 hour, pressing the button on the bottom of the drone shows me that the battery is full - but the LED on the front of the drone is still "breathing" - I can't believe it that the battery is not yet 100%!

Really depends on your charger, you need an 18watt charger (USB C to USB C) to get fast charging. With my anker charger it’s about 1.5 hrs from empty to fully charged. Does the lights on the bottom of your drone move fast or slow?

My charger supplies 2A. The 4 LEDs on the underside "run" through 1x in a second.
It's also not about "empty" to "full" - but about 80% to 100%. The 4 LEDs all light up - so the battery should have 95-100%.
It seems that the charging process would simply be time-dependent, regardless of the battery capacity. Because in 2-3 hours I charge an *empty* (10-20%) battery with the same charger with 2A...

The amperage is irrelevant to a degree in your case, it will be 5v at about 2A, a proper fast charger will supply ( in my case ) 12v at 1.5a and the light scrolls probably twice to three times every second. As for the battery showing 4 leds, it will show 4 leds from 80% ish to 100% charging slows down at that point.

Bottom line, your charger is insufficient.

ozoffi Posted at 2-4 03:38
My charger supplies 2A. The 4 LEDs on the underside "run" through 1x in a second.
It's also not about "empty" to "full" - but about 80% to 100%. The 4 LEDs all light up - so the battery should have 95-100%.
It seems that the charging process would simply be time-dependent, regardless of the battery capacity. Because in 2-3 hours I charge an *empty* (10-20%) battery with the same charger with 2A...

A 5v charger will take hours and hours to charge the batteries,   you really need the fast charger for them.