3 Month Old Phantom 4 Pro falls out the of the sky!

[zburninator]

Hello all,

I am new to contributing to this forum, however, I have read it for years now. I had my first complete drone failure and resulting crash (I have about 75+ hours on P4Ps) and I am dumbfounded by the lack of warning I received. The drone missed myself and two others by about 10 feet on its silent descent back to blacktop from 300ft, and I am convinced I need a ballistic parachute from here on out. As the title says, I lost a 3 month old P4P with less than 10 hours on it and no previous issues. After reviewing the log immediately prior to the final 45 second flight (DJI Go 4 did not record the final flight for some reason...I do have one last image however), I can see discrepancies with the battery voltage, however, I am not sure if the battery was the failure point, or the drone itself? Any insight is much appreciated. I landed the drone with 25% battery and no warnings as noted in the log file, and then proceeded to take off for another few, apparently fatal, pictures about 30 seconds later. I received no voltage warnings, the drone was hovering contently at 300ft, no stick input, still in the "green" of the battery bar when the video feed and motors quit at the same time (I noticed the lack of noise above). I recognize flying the drone with 25% battery is not necessarily the wisest thing to do, however, I have had no negative experiences to date and typically bring the drone down at 17% or so, trying to get every last minute of flight time. I am just shocked I received no warnings!

Has anyone else had similar experiences? Did you find it to be a drone, or battery failure? The drone is only 3 months old and still in warranty, however the battery in the craft was a little over a year old with 50 charge cycles (no deformation). I have seen no degradation since I purchased it (it is a standard battery from the Phantom 4 standard, not a high-capacity battery). I have included the final picture for fun/the timestamp in the meta data, as well as the log prior to the last flight...Thank god the SD card survived!

 

[Steve7777]

Previous flight log uploaded to viewer, for the convenience of all.

DJI Flight Log Viewer | Phantom Help

Upload and view flight logs from your DJI drones

www.phantomhelp.com

My layman's guess is that battery cell #3 died, and rapidly. It was looking 'iffy' for a lot of the previous flight and yet you say you received no warnings at all, which is strange. Taking off again was just enough to finish it off.

 

[Deleted member 62848]

I like your post cause it good read,,I myself had a free fall with p4s,turned out to be bad battery after heaps of charging,but went bad this day..someone here should make sense of your data eventually, me can't work that stuff out without software to read it,,,,,,,here's what mine did,,,100% on take off,straight to 400ft,,I get critically low voltage so I'm trying come down fast and in my direction,,got real wobbly and did not have much control ,thankfully I get it over me house before all motors stopped at 75ft,could just only watch it hit the concrete roof,broke roof and drone,out of warranty,1700 down the toilet,,have a new one again but it still not have my full trust after that incident,,,,since your covered they might not mention battery,,email them,,good luck and sorry about ya free fall

 

[Fly Dawg]

I recognize flying the drone with 25% battery is not necessarily the wisest thing to do, however, I have had no negative experiences to date and typically bring the drone down at 17% or so, trying to get every last minute of flight time.

There in lies the problem. Taking off with the battery level that low is a big no no. As was mentioned above, it appears that cell #3 was out of balance and very near the cut off level as shown below for a short period in this flight. Presumably by the time you reached altitude in the incident, that cell dropped below 3 volts which will shut the battery down. The battery needs to be recharged to re-balance the cells in order to reduce that possibility. Bringing the aircraft down at 17% is not an issue IF you began the flight with a fully charged and balanced battery.

 

[Starz]

Even though the op mentions that in previous or past flying experiences the low battery capacity issue has not presented any issues is probably more likely pure luck.
Hard lesson to learn.

 

[Andy9]

As Fly Dawg said taking off with 25% is the reason for the crash. No mystery here as the batteries are designed to shut off when one cell comes below cut off voltage. You must not rely on the % left and so recommendation is not to take off with low battery. At 25% is much more likely that one of cells comes to critical voltage value.
If you not take off with 100% full battery it is very wise to look frequently to the voltage level of cells. I have this data on the adjustable RC switch to get it instantly if I want.
And as you said after take off you send it straight up the motors were at full power and this also enhance battery to drain down faster.
At 25% you are a roulette player.

 

[Droning in AR]

I would never think of attempting even a SHORT flight if my battery was down to 25%.

 

[Not A Speck Of Cereal]

"Trying to get every last minute of flight time"

This is why I have 6 phantom batteries, so I don't have to worry about using the last of the juice of each battery. When I land and turn the bird off, that battery is done until re-charged.

I did a little of that my first year and was also lucky, but then started reading these "fall out of the sky" threads (and still do for reminders) and stopped doing that, so I didn't learn this hard lesson. I am only adding my comment here with thoughts of future readers.

Chris

 

[Capt KO]

Sorry for your loss but I’m glad to see this thread. It is a wake up call and I am going to change the way I look at my batteries from now on. And my take off charge. I also have one of the old standard batteries with about 50 charges. Setting my C button to battery level. Have fun fly safe.

 

[Starz]

Batteries have two values.
The cost for the battery and the cost of an aircraft.

 

[mwc13]

50% and landing, done

 

[Andy9]

If the battery is filled up to full at the same day or the day prior to the flight and you know that this battery has no issues then 50% is rather too high to get down.
I usually do that if I had filmed what I wanted and so no need to be in the air any more. Sometimes you need only few minutes to film the location. If the battery is above the 60% then the same day I fly with it. But at 30% it is wise to land. I know my batteries and all the cells are doing as it should then 30% is not very low. Of course at 30% it is better to be somewhere around your location not a mile away.