I use a drone that warns me if the votage gets under a defineted limit, than the controller beeps and it shows an alarm.
If the battery is warm and i force the 4 motors to 90%throttle it can kick in short, if i calm down and fly slower i can get some more seconds of flight as the voltage sag is not so bad when i fly only 60% throttle
I find that very conviniant as if it stayes under that level it constantly beeps and vibrates to warn me to land.
The warning is set at a level that allows about 30 to 60 seconds safe flight with much throttle while permanant alarm is warning.
That would give us a good indication not to use it further and land our gliders.
On the drone the voltage recovers after shut off for more than 0,4 volts, if battery cooles off but not more than 5 seconds after a new flightstart it will beep again constantly.
So the reading seems to be pretty correct even if battery is warm and if it was forced to max.poweroutput even at the end of the flight.
Btw. Flying with 60 or 70% throttle what means just hovering around the drone gives 11 min 30 flighttime, flying 8 figures with 80 to 90% trotle gives about 9 minutes flighttime with the drone- so not so much difference.
And there is a overload warning when flying full up anf forward a lpng time or when turn 180 degrees with full throttle.
It beeps and shows overload on remotedisplay.