Battery draining Culprit - Motor or ESC or Battery thy self?

Hi Arducopter Team ,

I am facing a severe problem for my drone which is indeginously made in India.
Configuration : Quad

Holybro Pixhawk , 40A ESC , Martin Tarot Motors - 380 KV , 6S HRB Battery.

Observation : for last few months is any new battery which is introduced in the drone will be good for first flight , second flight.
Mostly the third flight is one where the drone misbehaves and the drone decends very abruptly leads to abrupt landing and sometimes even the crash. ( Suffered Twice in the past)
The observation post assessment of the flights TLOGS , found that the voltage sags very drastically in linear manner and causes the dip.

After checking the battery 6S charge using LiPo checker / Battery charger found that it one of the cells is drained beyond 3.3V volt.

The reason we tried to find is battery management for charging and discharging , but now i am thinking that the 1 of the motor or 1 ESC is culprit which is pulling excessive current and causing every new battery to drain to the below nominal level of the charge.

Attaching the Tlog for diagnosis. Please let me know whts the issue. One Tlog is smooth flight of drone and another one is with voltage sag behaviour issue.

2022-12-05 11-45-56_goodflight.tlog (306.8 KB)
2022-12-05 11-50-57_battery_issue_flight.tlog (295.4 KB)

Tlogs don’t have much value for this purpose. Link to a .bin flight log file.

Please refer the dataflash log and help pls thanks.

In the last log there, you’ve got a couple of motors running near absolute maximum the whole time, and one motor doing hardly anything. This might be exceeding the batteries limits, unsure.

So the weight distribution is very bad, or the motors and props are not all the same.
and do this ESC calibration procedure

Now - voltages! You’ve got nothing set. A drone pilot cant watch and control what is going on and still manually monitor battery voltages. This is one of the reasons we have a flight controller.
I would bet that the batteries are being over-discharged because the correct battery settings are missing.

  • Connect to MissionPlanner, go to Mandatory… Initial Parameters
  • Put in your prop size and number of battery cells (and select a chemistry too if it’s not Lipo)
  • Accept everything it offers including the battery failsafe actions.

Also set
And let’s see the next log, just some gentle hovering and pitch/roll, nothing aerobatic.

Hey Shawn , thanks for key details. Will make the settings and update the flight how is it behaving.

After making those changes and testing, if motor outputs are still near maximum then you will need to change motor and prop selection (at least) , lose some weight, or entire redesign.

IF everything is working and motor outputs are reasonable, then you will need to retune (Autotune) after these changes.
But we will know more after the test flight and log file.