Battery voltage reading from FC incorrect

With a 3s 6000mah at 12.2 volts on a 500quad and After 2 or 3 mins of flight time MP And pixhawk cube will alarm battery failsafe Showing 9.2, but once back on the ground MP and battery voltage monitor attached to balance plug shows battery at 12…0

Do you have a log of that flight.
Cant say much without it other than you have a poor battery.

Ok Not sure which file the log or bin file

The .bin file from the Flight Controller

See your other post for more replies

Battery terminal voltage will drop (sag) with the battery is under a load. Battery terminal voltage will recover to its REST voltage when the load is removed.

Ok, that’s good to know, will that drop in voltage do damage to electronics and how do I disable the battery fail safe in order to elevate the warming alarm
I have battery alarm connected to the balance plug

The last thing you want to do is disable the low battery fail safe.

If your balance lead alarm is not going off, then chances are very good that you need to calibrate the Pixhawk currnet and voltage sensor.