Mavic Pro dropped out of the sky

[BudWalker]

All good points, although based on previous files, even twice the current draw would not kill it fast enough. The motor data are logged at 50 Hz.

This from a .DAT where the Mavic was in Sport mode and current 20.5. Even then the voltage drop can be seen at the very end.

@Cyberpower678

 

[Alex.ter]

This from a .DAT where the Mavic was in Sport mode and current 20.5. Even then the voltage drop can be seen at the very end.
View attachment 24140
@Cyberpower678

So does that show that the motors lost power?

 

[sar104]

So does that show that the motors lost power?

Motor volts are the easiest 50 Hz reference data. They show that the motors lost voltage, even though the motor PWM remained high, which indicates that the power supply had collapsed - obviously due to a battery disconnect in this case.

 

[Alex.ter]

Motor volts are the easiest 50 Hz reference data. They show that the motors lost voltage, even though the motor PWM remained high, which indicates that the power supply had collapsed - obviously due to a battery disconnect in this case.

But when it was falling the motors were spinning and leds were on, when it was falling it was upright and not tumbling, and props were spinning cause if they weren't the drone would be tumbling and fast this was kinda like landing very fast

 

[BudWalker]

So does that show that the motors lost power?

Well, the motors lost power because the voltage available to them dropped. Normally, the motors have full voltage available and it's the PWM (Pulse Width Modulation) that determines what percentage per unit time that the voltage is used.

Why you may ask would motorVolts be used as a proxy for the system voltage. The battery voltage that CsvView/DatCon knows about is only 1 Hz and there is a 1.5 second delay. The motorVolts at 50 Hz is much faster.

 

[BudWalker]

But when it was falling the motors were spinning and leds were on, when it was falling it was upright and not tumbling, and props were spinning cause if they weren't the drone would be tumbling and fast this was kinda like landing very fast

Looks like the incident happened at 18:30 local. You were 232 meters from the AC. Could you see it well enough to know that it wasn't tumbling?

 

[Alex.ter]

Looks like the incident happened at 18:30 local. You were 232 meters from the AC. Could you see it well enough to know that it wasn't tumbling?

Yea it was 6:33 was pretty dark all ready so I saw the leds clearly on, and I believe I heard the props spinning maybe not don't remember clearly, but by the leds I could see it was going down fast but was upright the whole time until it went behind a house and I heard a loud crash

 

[ac0j]

How can you tell if the voltage drop happened BEFORE it hit the ground?

 

[Alex.ter]

How can you tell if the voltage drop happened BEFORE it hit the ground?

The file stops abruptly before it even started falling, it flew 50 more feet after the file stopped, then fell

 

[Cyberpower678]

The file stops abruptly before it even started falling, it flew 50 more feet after the file stopped, then fell

Actually this sounds familiar to another case on this forum. DJI, IIRC, replaced it under warranty. The drone was hovering then fell down while still powered on. The owner created a video to demonstrate the failure. When we looked at the logs, some aspects of the abruptly stopped recording new value and froze. The internal computer crashed mid-flight. @BudWalker remember that one?

 

[Cyberpower678]

In the case I described above, I speculated to the possibility to a final FINAL failsafe of the drone. In the event of a total system failure, the power is cut to the propellors after a few seconds of timing out.

 

[BudWalker]

Actually this sounds familiar to another case on this forum. DJI, IIRC, replaced it under warranty. The drone was hovering then fell down while still powered on. The owner created a video to demonstrate the failure. When we looked at the logs, some aspects of the abruptly stopped recording new value and froze. The internal computer crashed mid-flight. @BudWalker remember that one?

You're probably thinking of this one
Mavic Disconnects and Motors Shut Off (VIDEO)

 

[sar104]

But when it was falling the motors were spinning and leds were on, when it was falling it was upright and not tumbling, and props were spinning cause if they weren't the drone would be tumbling and fast this was kinda like landing very fast

Your comment that lights were on was one of the reasons that I discounted a battery disconnect as the cause. That plus the lack of any record of voltage drop.

 

[Alex.ter]

Your comment that lights were on was one of the reasons that I discounted a battery disconnect as the cause. That plus the lack of any record of voltage drop.

Got an email from dji...

 

[sar104]

Got an email from dji...

So non-warranty, and they are charging you $5 to fix it?

 

[Alex.ter]

So non-warranty, and they are charging you $5 to fix it?

$129
The list keeps going

 

[Alex.ter]

$129
The list keeps going

 

[sar104]

No explanation? The DAT file suggested sudden hardware failure. They usually seem to include some kind of assessment to support their conclusion.

 

[Alex.ter]

No explanation? The DAT file suggested sudden hardware failure. They usually seem to include some kind of assessment to support their conclusion.

Who should I email? Because I don't want to pay $129 if it wasn't my fault

 

[sar104]

Who should I email? Because I don't want to pay $129 if it wasn't my fault

I would ask whomever you are dealing with at DJI for an explanation as to why it is not a warranty issue.