175 feet straight down slamming onto a frozen lake!

[dorbot]

The spring is gone too, that should be captive. But the spring could have been lost post impact. I hope it wasn't missing before flight.

Perhaps the motor loads were massive as it tumbled and that killed the voltage on a weak cell as it tumbled?
But I cant tell what the other voltages are doing at the same time.
Again just speculating....

 

[The Famous]

To be fair, AirData tells you just as much as PhantomHelp in the downloadable CSV file, and also has greater in-depth analysis of the power and sensor data than PhantomHelp, but only if you have one of the paid subscriptions.

Won't let me upload CSV file. Says "The uploaded file does not have an allowed extension". Having trouble with Ipad! Password stuff!

 

[sar104]

Won't let me upload CSV file. Says "The uploaded file does not have an allowed extension". Having trouble with Ipad! Password stuff!

I'm not suggesting that you upload the CSV file - just the AirData link that will let us download it. But as I mentioned previously - I think we really need the DAT file.

 

[Fly Dawg]

Won't let me upload CSV file. Says "The uploaded file does not have an allowed extension". Having trouble with Ipad! Password stuff!

As @sar104 mentioned,if you have already uploaded your file to Airdata,( which we assumed you had) share that link here and we can download in csv from there.

 

[The Famous]

Will this help until I get help with my iPad?

 

[The Famous]

Airdata UAV - Flight Data Analysis for Drones

 

[sar104]

Airdata UAV - Flight Data Analysis for Drones

That looks like a faulty battery. Cell 1 collapsed at 219 seconds and dropped the voltage below the protection shutoff level. The battery only had 50 cycles, I would ask DJI to cover it.

 

[loktite]

So what is the reason for immediately shutting the bird off, to prevent a possible fire/explosion? My first thought was it'd be better for them to put it into the 10% battery protocol, but I don't really know the dangers of the LiPo cells in this case.

 

[The Famous]

The spring is gone too, that should be captive. But the spring could have been lost post impact. I hope it wasn't missing before flight.

Perhaps the motor loads were massive as it tumbled and that killed the voltage on a weak cell as it tumbled?
But I cant tell what the other voltages are doing at the same time.
Again just speculating....

What spring are you referring to?

 

[dorbot]

In the 1st and 4th picture the motor shaft can be seen but the conical spring that normally sits on the shaft which secures the quick release prop is missing. Unless it is the older design with the spring plate and bent tabs that perform the same function. I didn't think of that till just now.

Edit. Yeah my mistake, on closer inspection there are no coiled springs in this design. It is using the bent tabs not a conventional spring.

 

[dorbot]

That looks like a faulty battery. Cell 1 collapsed at 219 seconds and dropped the voltage below the protection shutoff level. The battery only had 50 cycles, I would ask DJI to cover it.

View attachment 93572

So immediately after take off the battery voltage dropped to just above 3.6v per cell when loaded. Is that normal?
Seems a bit low to me.

 

[Boofritz]

Was a very short flight ( 4 minutes) to video some ice fishermen. Using Litchi (as I always do). Was just finishing up when a Battery warning came on! Noted "Battery, Cell #1" can't remember the whole warning. Lost connection at that point. Waited for Return Home as it has always done in the past. Never came back. Went about 100 yards out on the ice and there it was. Upside down. No lights on the battery. I turned the battery on and the craft made the starting sound and one prop moved. How do I check batteries? Any thoughts?

Wow that really got smashed / mine went out of control at 200 meters it did a spiral down fall so it may have had a little lift / one leg had a small crack and broke a prop and I still don’t know what happened

 

[sar104]

So immediately after take off the battery voltage dropped to just above 3.6v per cell when loaded. Is that normal?
Seems a bit low to me.

It would be low for a fully charged battery, but this wasn't.

 

[gmann21133]

I have had two batteries develop errors over the last two weeks. I had an error that stated it was a “critical battery error land soon”. I had been flying for about 4 or 5 minutes. I was bringing the Phantom 4 close to me, and decided to take one more picture about 8’ above the ground. That was my fatal error, when I clicked the shutter button it dropped. Truth be told if I had landed instead of trying to take one more shot the bird would have survived. I’m just wondering though if there is some sort of battery issue that may need to be addressed.

 

[chinaevacase]

i am very sorry to hear that, how to get it back?

 

[dorbot]

83% is still pretty well charged though.
The remaining capacity falls with voltage but its not linear because as you go down in voltage any given voltage fall has more impact on remaining capacity.
Li-Po voltage range is 3.2- 4.2 volts per cell with 3.7 volts nominal, centre of the range.
The BMS will turn off the cell at 3.2 volts.
But you are never meant to get anywhere near that, a forced landing will leave you with more than 3.2v, so I would expect a voltage of 3.6 volts per cell to read much less than half capacity remaining.

In this incident at 3.6v the % remaining never went below 70%. Its like the battery was not calibrated. The battery temperature seemed normal throughout, 18-27ºC.
Was this battery ever deep cycled to 8% or even low voltage cutoff and then fully charged? The alleged method of calibration? I know there is some debate as to whether or not this is good practice. DJI seem to have changed their mind on the issue.

 

[sar104]

83% is still pretty well charged though.
The remaining capacity falls with voltage but its not linear because as you go down in voltage any given voltage fall has more impact on remaining capacity.
Li-Po voltage range is 3.2- 4.2 volts per cell with 3.7 volts nominal, centre of the range.
The BMS will turn off the cell at 3.2 volts.
But you are never meant to get anywhere near that, a forced landing will leave you with more than 3.2v, so I would expect a voltage of 3.6 volts per cell to read much less than half capacity remaining.

In this incident at 3.6v the % remaining never went below 70%. Its like the battery was not calibrated. The battery temperature seemed normal throughout, 18-27ºC.
Was this battery ever deep cycled to 8% or even low voltage cutoff and then fully charged? The alleged method of calibration? I know there is some debate as to whether or not this is good practice. DJI seem to have changed their mind on the issue.

These batteries often give misleading starting percentages when flown from other than fully charged, so I don't think that was particularly a problem with this flight. The major deviation of one cell was the problem - that is definitely abnormal and I doubt that a discharge and charge will fix that, but it's worth a shot.

 

[The Famous]

Thanks everyone for the input! Think I will get a Cell Tester! I had trouble charging that battery a week ago. Lights kept blinking in sequence, wouldn't turn off. Next day it charged fine and flew it with this battery 4 times. Should have taken the warning!

 

[fatmaggots]

I’m sorry to hear about your experience. I suffered a similar fate in November of 2017. My P4+ fell off the sky from 87 feet, so I can relate to your plight. DJI replaced my broken bird with no questions asked. While waiting for the bird, I bought a second P4+ (obsidian).
It was much fun flying before I experienced that crash. After that, caution and even fear seem to have dulled any fun for me. From reading this forum, reports of drones falling out of the sky or flying away seem to be too frequent. In many instances, User error plays a part but not predominantly the reason for these crashes and fly always. Is DJI doing anything to improve flight experience and reassure drone pilots? Does anyone know if these challenges are the result of hardware or software problems? How can I regain my confidence and fun in flying further?

 

[sar104]

I’m sorry to hear about your experience. I suffered a similar fate in November of 2017. My P4+ fell off the sky from 87 feet, so I can relate to your plight. DJI replaced my broken bird with no questions asked. While waiting for the bird, I bought a second P4+ (obsidian).
It was much fun flying before I experienced that crash. After that, caution and even fear seem to have dulled any fun for me. From reading this forum, reports of drones falling out of the sky or flying away seem to be too frequent. In many instances, User error plays a part but not predominantly the reason for these crashes and fly always. Is DJI doing anything to improve flight experience and reassure drone pilots? Does anyone know if these challenges are the result of hardware or software problems? How can I regain my confidence and fun in flying further?

I've examined and analyzed enough flight logs here to know that user error is unquestionably the predominant reason for crashes and "flyaways". I'm not sure how you got the opposite impression.