Crashed my phantom4 for unknown reason

[gerrie8181]

Hello all,


I am relative new to this and bought my Phantom 4 pro 3 weeks ago. I flew in beginner mode the first 8 to 10 flights and learned to fly with several tutorials on the internet. Did not fly very far away to get more comfort in flying. Yesterday had a great flight to a mill and toke some movies and pictures in a 11 minutes fly with a distance in total of 2700 meter. So that was awsome and today went out for a movie of my house and the surroundings.


But... the flight ended with tears... I am so careful with my drone but it happened... the drone crashed from 12 meters into the groud. Camera broke, props broke. Replaced the props and tried a short flight and the drone seems to be OK (despite some scratches..) but the camera is broken....


Looking into the flight record:

Took off and went some rounds about the house at a height about 10 to 57 meters. Toke some nice picturs and movies. Oh, I started with *100%* battery. Took some distance (not very much) and new pictures and movies. Then decided to climb to 125 meter (maximum I installed in the settings) and hover some time, turned and took pictures and movies. This was at a flight duration of 12:20 when I reaced the 125.0meters. Battery was 49%. I wanted to take some more pictures with different settings and then go back to ground.


At 16:14 flight time and 32% of battery I got the message: "Warning: Motor overloaded. Aircraft will decelerate to ensure safety”. The message made me shocked and I decided to go back to ground directly and put the left stick down 100% all time (flight time 16:19 and battery 32%). The drone was descending with vertical speed about 10 km/h but that was done before and should not let to any problem I was thinking. At 60.0m height, flight time of 16:42 the battery was dropped to 27% and I got the message: “Obstacle Avoidance will be disabled in landing” and “Tips Critically Low Power. Aircraft Landing. Throttle up to reduce the speed of descent and use sticks to avoid obstacles”. This message was on screen very short time


At 16.43 flight time, battery of 27% and height of 55.0meter it was telling with a warning sign: Battery: Low Voltage Protection. Still descending… At 16.44 Flight time, height 51.0 meter the battery runs to red 0%! At 37.0 meter and 16.49 flight time the warning came again. Aircraft went out descending faster according to flight record and descending. At 16.53 flight time and 12.0 meter height it gave the Overloaded warning again and then suddenly it felt to the ground from 12 meter height…


I am very disappointed. As far as I can see I did not do anything wrong. Got the safety message and decided to bring the aircraft back immediately.


Who can help me? I definitely have to bring the drone and camera for repair but am wondering if it was my fault (just tell me please) or it was a buggy drone? Still confused. Happy to share flight records for analyzing. How?


Regards,

Gerben

 

[Suhail78]

upload your logs and post a link back to this thread so people here can take a look...

DJI Flight Log Viewer

 

[gerrie8181]

Here it is:
DJI Flight Log Viewer - PhantomHelp.com

 

[Bakersfield Quad]

Your battery cells don't look good, #4 cell looks bad.
You dropped from 27% to 0% instantly, but cell deviation was going down hill for 20-25% from 50%.
Battery failure likely, might be saved with a discharge cycle, but don't fly It!
You need to contact DJI, let them see what happened.

 

[microlinux]

It looks like you ran out of battery (and/or the battery is bad), but there are others here with more experience than I at dissecting these things. It's important to watch battery voltage, not the % remaining. The % is just an estimate. I find it helpful to use the C2 button as a shortcut to display battery info.

 

[Suhail78]

What % do you have your battery alerts at? i usually set the low battery warning to 30%, and the critical to 15%

 

[gerrie8181]

Yes, 30% and 15%

 

[Meta4]

Battery cell voltage drops as the battery is being used.
If your battery isn't giving >3.3 volts per cell you are in trouble.
Unfortunately yours got into that territory from 16:05.9 when the Phantom was 410 feet up and you delayed bringing it down until 16:18.2.
A normal descent from that height would have taken 42 seconds but the battery didn't have enough to give you power for that long.

Talk to DJI about the incident.
It looks like the battery was sick right from the start.
At 100% it should be giving 17 volts but you were only getting 15.8 V

 

[Traveler]

Battery cell voltage drops as the battery is being used.
If your battery isn't giving >3.3 volts per cell you are in trouble.
Unfortunately yours got into that territory from 16:05.9 when the Phantom was 410 feet up and you delayed bringing it down until 16:18.2.
A normal descent from that height would have taken 42 seconds but the battery didn't have enough to give you power for that long.

Talk to DJI about the incident.
It looks like the battery was sick right from the start.
At 100% it should be giving 17 volts but you were only getting 15.8 V

Meta, you made a good point about the starting voltage, yet the app was reporting 100%. Any thoughts on why this would look like a full battery when it obviously wasn't? My guess is faulty battery electronics, or the cells are so weak that they show 17 volts under no load.

Good analysis BTW!

 

[Meta4]

Meta, you made a good point about the starting voltage, yet the app was reporting 100%. Any thoughts on why this would look like a full battery when it obviously wasn't? My guess is faulty battery electronics, or the cells are so weak that they show 17 volts under no load.

The % indicator is only approximate (but good enough for a good battery).
The only thing that matters to the Phantom is the voltage it puts out.
We know that a partially discharged battery will have problems that can make the % indicated very misleading.
Whatever was wrong with the battery had a similar effect.

 

[sar104]

I'm not convinced that any of the battery cells are bad - it looks more as if the software was mis-reporting. If you look at the voltage progression on all the cells it appears fine, even though they seem to start a bit low, until it falls of a cliff at around 900 seconds. That's short in terms of flight time, consistent with not having a full charge. The abrupt end is consistent with the software starting the flight at 100% when it should probably, based on voltage, have been around 70%.

 

[gerrie8181]

Hello all, thanks for all feedback. For me personal the issue still hurts and maked me having a bad feeling about it but will sort it out.

Today I had some email conversation with DJI support. They reacted very quick on mails but they do not want to examine the flight logs. They want me to sent the drone, the examine logs by an engineer and then decide further on. Is this normal?

They only talk about repairs. When I asked for a full product replacement because in my opinion a pretty new battery of 3 weeks and 15-20 flights caused for these problems they do not answer this. All they told me is to go through the repair process. What is your opinion, do I need to accept this? And I assume they should not only take care of my drone but also deliver me a brand new and working battery!

Looking forward to your replys.

 

[Bakersfield Quad]

This is how it is done, it is that or fix it yourself.

 

[Goof]

I'm not convinced that any of the battery cells are bad - it looks more as if the software was mis-reporting. If you look at the voltage progression on all the cells it appears fine, even though they seem to start a bit low, until it falls of a cliff at around 900 seconds. That's short in terms of flight time, consistent with not having a full charge. The abrupt end is consistent with the software starting the flight at 100% when it should probably, based on voltage, have been around 70%.

View attachment 87165

Where did that chart come from? "50% battery" is not 2.5V, 2.5V for a battery cell is dead battery territory. GO App / the aircraft itself is grossly misreporting or completely ignoring cell voltage for some reason.

That cliff you see after 3.5 is exactly what LiPos do, the app should be reporting 0% here, and the bird should've landed well before that point. This should be a relatively straight forward warranty case with DJI, although they seem to prefer refurbs over brand new replacements.

 

[sar104]

Where did that chart come from? "50% battery" is not 2.5V, 2.5V for a battery cell is dead battery territory. GO App / the aircraft itself is grossly misreporting or completely ignoring cell voltage for some reason.

That cliff you see after 3.5 is exactly what LiPos do, the app should be reporting 0% here, and the bird should've landed well before that point. This should be a relatively straight forward warranty case with DJI, although they seem to prefer refurbs over brand new replacements.

The chart data are directly from the log file for the flight in question. I agree completely about 50% not being 2.5 V - that was exactly the point I was making about the software mis-reporting.

 

[Goof]

I'm sorry I can't be of more help :\ I do know though that there is an option in the GO App to show the individual cell voltage on the home screen, hopefully this will allow you to keep an eye on it in future. I'm not sure if it displays the lowest cell or an average though, I think it's the former, but that's only really a guess.

At least if you can see the cell voltage, you can instantly recognise if the percentage reading is off like it was here, and land early.

 

[goose342]

There was a solar flare on Monday. Not saying that it had an effect but there is an app called magnetology that measures those high reading. Don't fly on those days or at least be informed.

 

[Meta4]

There was a solar flare on Monday. Not saying that it had an effect but there is an app called magnetology that measures those high reading. Don't fly on those days or at least be informed.

The solar flare had no effect.
There's never been any documented solar flare effect on anyone flying a Phantom.

 

[ribjig]

They only talk about repairs. When I asked for a full product replacement because in my opinion a pretty new battery of 3 weeks and 15-20 flights caused for these problems they do not answer this.

Am newbie like you, with P4P+.
Whilst under warranty, DJI pays shipping both ways.
Had camera replacement twice so far, different reasons.
IMO, you assume results of repair give you a perfectly
working P4P+. No cost to you, other than shipping time
& repair time you are without your drone...

Addicted to drone flying daily? Get a cheap 2nd drone
to play with whilst P4P+ being repaired...?

 

[gerrie8181]

Today I received my drone back. I thought it was repaired but it is a brand new one. Did some test flights and am a happy men again!

So in general for future: i have to look ar voltage and not to battery%? So what are important threaholds for the battery to watch?