DJI Drone Help Forum

P4Pro put of sky into lake. Covered by warranty?

Hi Guys,

Just after some quick opinions, my P4P fell out of the sky a week or so ago and into a lake. It was unrecoverable.

https://www.phantomhelp.com/logviewer/HCJ3E6RPCODTDVBFYL07/

I’m after opinions as to whether this would possibly be covered by DJI under warranty from the educated folk here. It’s outside the 1 year warranty period but I’m pretty sure it’s a manufacturer issue.

Thanks,
Dan

While your flight log doesn’t show the cause of the sudden disconnect at the end, I suspect it was due to a battery failure. Cell #1 was about 0.5 volts lower than the other battery cells during most of the flight that occurred out over the water. And it had some unusually high spikes that did not seem to be caused by your stick movements. For example:

  • At 1m 40.7s, it spiked down from 3.618V to 3.044V
  • At 2m 35.7s, it spiked up from 3.084 to 3.458
  • At 2m 38.7s, it spiked down from 3.467 to 3.124

If that cell spiked downward at the end of the flight log, that likely would have caused the battery to shut off mid-flight.

As mentioned by msinger, it appears you had a battery cell drop below the cutoff value at approx 100 seconds. RTH continued for approx another 37 seconds and Cell #1 remained below 3.2v for the remaining period before the end of the data. The other issue is that you took off with only 52% battery charge. This “might” be an issue, if you are looking for warranty support.

One of the main reasons for topping off a battery before flight to100% is the rebalancing of the cells of the battery that occurs at the end of the charge. After a battery has started its automatic storage discharge, the cells quickly become unbalanced, as there is no cell balancing during the storage discharge. A variation in cell voltage between cells of a full 0.5V is very dangerous, as when any single cell voltage ever drops below 3.00V, the battery shuts off, to protect the battery, even if in flight. Always top off your batteries before flight, especially if there is any chance they have entered into the storage mode discharge cycle. Lesson learned the hard way myself, on a P3P that came crashing down 15 feet from me from 200 feet above me, 20 seconds into a test flight, on a battery that showed 85% charge, but had entered actually already into storage discharge, unbalancing the cell voltages!

Interesting info thanks.

Is this mentioned anywhere? I can’t remember seeing it/reading it but it may have been a while ago.

I’ve emailed DJI so I’ll see how I go.

Thanks

Which part?