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hemant dalal

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hi, i was shooting a venue and suddenly my Mavic air came down too low on the road and crashed with a running car. broke two of its arms and damaged substantially. What to do next? kindly advise
 

slup

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Hi there & welcome to the forum ... or actually congrats to your first post since you joined 2019 👋 :D

... suddenly my Mavic air came down too low on the road and crashed
Was this sudden descent commanded by you ... or was it uncommanded?

This makes a big difference ... if you by yourself steered it down & unintentionally came to low ... it's considered as a pilot error & you can only rely on DJI Care if you have that ... otherwise all repair costs will be fully on you.

If the descent instead, as far as you know, was uncommanded & you want help by someone here at the forum to figur out a possible reason ... you need to share the flight logs from that flight. The flight logs are stored in the mobile device you flew with ... go here & read up on how to retrieve them (read under section 3. & about the mobile device .txt logs) --> Mavic Flight Log Retrieval and Analysis Guide then come back here & attach the log in a new post.

If it turns out that this was without you to blame ... you can claim warranty if your MA1 still are within the warranty period ... if not go for DJI Care if you have that ... or again pay from your own pocket if neither of the other 2 applies.

What to do next? kindly advise
If you feels that the descent was uncommanded & you want a second opinion out from the logs ... you share the logs here in this thread & someone will assist you, then you contact DJI through below link.

If you already knows that this mishap all are on you ... contact DJI directly for a repair cost estimate through this link --> DJI once you have set up a repair request DJI will guide you to what you need to do, they will also see if warranty or DJI Care applies.
 
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tlswift58

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Start a "claim" with DJI. They'll have you submit log files / etc to determine "WHO" covers what. They will then have you send in the drone for repairs.
 

hemant dalal

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Hi there & welcome to the forum ... or actually congrats to your first post since you joined 2019 👋 :D


Was this sudden descent commanded by you ... or was it uncommanded?

This makes a big difference ... if you by yourself steered it down & unintentionally came to low ... it's considered as a pilot error & you can only rely on DJI Care if you have that ... otherwise all repair costs will be fully on you.

If the descent instead, as far as you know, was uncommanded & you want help by someone here at the forum to figur out a possible reason ... you need to share the flight logs from that flight. The flight logs are stored in the mobile device you flew with ... go here & read up on how to retrieve them (read under section 3. & about the mobile device .txt logs) --> Mavic Flight Log Retrieval and Analysis Guide then come back here & attach the log in a new post.

If it turns out that this was without you to blame ... you can claim warranty if your MA1 still are within the warranty period ... if not go for DJI Care if you have that ... or again pay from your own pocket if neither of the other 2 applies.


If you feels that the descent was uncommanded & you want a second opinion out from the logs ... you share the logs here in this thread & someone will assist you, then you contact DJI through below link.

If you already knows that this mishap all are on you ... contact DJI directly for a repair cost estimate through this link --> DJI once you have set up a repair request DJI will guide you to what you need to do, they will also see if warranty or DJI Care applies.
 

hemant dalal

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Thanks for the valuable info.

I checked the log. what i noticed that suddenly the battery died 60% to 0% and the aircraft started landing on its own. can i report to DJI for this? there was no fault of mine i suppose. Unfortunately i am not having DJI care for this. I am attaching herewith the log files, which clearly mentions that the flight battery dropped from 60% to 0 all of sudden, and drone started descending. Can i claim compensation from DJI?

Thanks again.
 

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slup

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... suddenly the battery died 60% to 0% and the aircraft started landing on its own.
As you haven't shared the complete mobile device .TXT log from the flight I can't say what cause that.

But ...

From seeing a huge number of similar cases before, where the battery percentage suddenly goes to 0% followed by a forced auto landing I can say that this was due to that one or several cells in your battery failed & the voltage fell below 3V.

The reason that the BMS (battery management system) initially reported 60% but then dropped to 0% comes from that the battery cells didn't behaved as expected. Initially when the BMS made the percentage calculation the total battery voltage corresponded to 60% ... when the calculation was made the BMS started to count down percents by keeping track on how many mAh that was being consumed ... but as your battery was faulty the voltage dropped much faster & suddenly the BMS realized that the percentage estimation was wrong & fell back to 0%.

The reason for a battery cell failure usually lies in how the battery have been treated in the past ... below you have general info about LiPo & LiIon batteries & how you should take care of them ... I'm pretty sure that you will find several thing's there that can explain why your battery died.

  • Keeping the battery at 100% isn't good for it ... do what you can to minimize the time that they are at that level, the default up to 10 days auto discharge down to 60-65% is way too long ... & if you check the level by pushing the button you reset the counter & the 10 day counter will restart. If a battery that is above storage % level haven't been used in a couple days, use the USB adapter from the Fly More Kit to charge something else (your phone) in order to bring it down to storage % (see below ...)
  • Heat kills them ... don't store above room temperature & absolutely not in a car during summer, a couple hours in a burning hot car & the battery have sustained serious damage.
  • Let them cool down to room temperature before recharging them.
  • Don't fly with a battery colder than 15C degrees, keep them warm in colder weather, have them in a pocket close to your body.
  • Store the batteries between 40-60% ... a good thumb rule is to take them of the charger as soon as the third led start to blink, then they are just over 50%. But anything between 1 solid + 1 blinking up to 2 solid + 1 blinking is good enough.
  • Don't drain them to low, make sure they don't go under 15% ... once in a while, so be it. Set the ambition to not have them lower than 20% ... if you aim for that you usually don't end up below 15%.
  • Don't fly with a battery not recently fully charged, having a battery laying around partially charged for a longer period may make the cells in the battery unbalanced, using a unbalanced battery can make that lower cell fail soon after take off, & initiate a forced low battery auto landing you can’t stop.
  • If stored for a long time, cycle them at least once each third month ... then back to storage %.

First of all ... batteries will not last forever

...they will either slowly degrade until the point where the useful flight times are so short that you stop using it

...or it will have a sudden cell failure which will trigger a sudden forced auto landing in the worst possible place

...or it will slowly start to swell to the point where they not fit into the drone anymore


...or the swelling goes off instantly or gets worse when the battery gets hot & push itself out of the drone at height.

The only visual sign is swelling ... which not always occur. Furthermore different drone models have different possibilities to handle a smaller momentary swelling when hot during flight.

So a battery can't be judged only by that it take charge to 100%, isn't swollen & manage to power your drone without mishaps ... too much is going on hidden from just a visual inspection or a test flight, you may have been on the verge to a disaster without knowing it.

You have mainly 2 methods to both prolong the useful service life of the battery & prevent sudden failures ... & judge when it's time to either limit the flight duty (in colder temps for instance) or completely take it off flight tasks.

1.Battery Care
...Never keep the battery cell voltage outside 3,7-3,8v for a longer period than 48h (that is a battery charged to approx 50%). If too high after a flight, discharge them, too low charge them up to storage level again.

...Store them in room temperature ... (too warm is more damaging than too cold)

...Never let them overheat ... (left in the sun or thrown in a hot car)

...Don't charge them hot, let them cool down to room temperature

...Don't use cold batteries, try to have them at room temperature before using them

...Respect the operational ambient temperature specified in the user manual

...Don't push the battery for amp draw (both sticks on max inputs at the same time in Sport mode) when cold or hot ambient temps

...Don't fly them below 15% other in exceptional cases

...Always start a day of flying with the batteries freshly fully charged

2.Battery performance follow up over time
...Follow how the useful calculated max flight time change

...Compare the full charged max mAh compared to the designed mAh

...Monitor how the cell deviations degrades

For all points regarding the battery performance it's a question about trends over time ... just looking at a single flight will not give any insight over the actual health ... having a bit shorter flight time or some bigger cell deviations in one flight can be normal if using Sport mode or flying in colder ambient temps for instance. The paid Airdata subscriptions give the possibility to check these trends over all flight logs uploaded there ... it gives a good decision base to understand the battery health & if it's time to take it off duty.


...can i report to DJI for this? there was no fault of mine i suppose. ...Can i claim compensation from DJI?
As your battery incident most probably is due to how you have cared for them ... it's not DJI's fault. Besides that, DJI only give 12 month battery warranty ... so outside that period all will be on you, no matter the reason.
 
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hemant dalal

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Thanks for the detailed reply. Really appreciate the same. Will look forward to follow these when I will buy my next toy. Looking forward to have one soon.
 
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