Use of battery after crash

[aeriaxyz]

Hi,

Back in March I had an incident where my P4Pv2 hit a guy wire on a tower, broke a prop and fell down from a little under 150 feet. Upon touching the ground, in snow (which absorbed a good part of the impact), the battery got ejected. Now, I know the battery wasn't the cause of the crash. I also know it looks perfect from the outside. No cracks, it charges, powers up the drone.

Would you advise I keep using this battery? I don't think I should, but perhaps i'm being too cautious.

Thanks

 

[Saladshooter]

It should be fine.... put it in the drone then look at the battery stats for the individual cells.... if they are fairly equal, then all should be well.

 

[Andy9]

I agree. Make the first flight close to you and not very high and do it till the batt drains to 20% or so.
Then put the flight data on Air data UAV (or something like that) and look for the cell diferences.
If the batt will perform well, then it'll be OK to fly with.

 

[kilhan]

But it is very important to change ALL the propellers after the crash. Even those looking good can have microfractures which can cause another accident.

 

[aeriaxyz]

But it is very important to change ALL the propellers after the crash. Even those looking good can have microfractures which can cause another accident.

Yes they were changed, the unit was repaired at DJI.

 

[Fabian Sylvester]

I agree. Make the first flight close to you and not very high and do it till the batt drains to 20% or so.
Then put the flight data on Air data UAV (or something like that) and look for the cell diferences.
If the batt will perform well, then it'll be OK to fly with.

Good day all. I agree with this method as I have done it after a crash last year when my drone (P34K) fell out of the sky due to total power-cut. The test was to determine if the problem was 'drone' related or if it was specifically 'battery' related.
First I did the following five GENERAL drone integrity tests which were done indoors with no propellers:
1. Power On (and self-test with beeps, blinks)
2. Motors-Start
3. Joysticks Responses (Pitches, Rolls, Throttles and Yaws)
4. Hover Simulation (To see if unit reacts to/opposes movements while it THINKS it is airborne)
5. Telemetry Transmission (To see if unit still has telemetry transmission abilities)

After passing all above tests, it was time to test the bird's ability to do a successful/stable launch, successful/stable hover and successful/stable flight.
For the hover and flight, I simply kept it about just a few feet off the ground which was soft lawn (just in case it fell out the sky again), and allowed the battery to drain all the way down to Critical when it landed itself successfully.
HINT: This can take well over 20 minutes due to your bird's expected battery-life so I suggest initiating a video recording (4K) which would obviously speed-up the battery drain process.
AFTER MY SECOND crash when it fell out of the sky again due to total power-cut, I FINALLY LEARNT about flight data diagnostics which revealed that I had Major Deviations in Cell 4. and thus, that battery was discarded.

According to AIRDATA UAV:
"Major deviation is when a cell differs more than 0.07v from the other cells.
Please note that normal batteries can have a few of these.
An abnormal battery will:
A) Have most of the major deviations in one cell
B) There will be multiple major deviations per minute, and more than 10 total
C) The deviations continue longer than 1 minute
If your battery shows all symptoms (example, another) then this is considered a more severe case of an inefficient battery and may impact the battery life.
If your battery has only 1-4 instances on the same cell, don't worry too much about it. If it has 5-10 instances - then continue to track and make sure it does not degrade:"