Repair Invoice.......... REALLY?????

[brett8883]

Is there a reason you didn’t post the most recent one?

 

[Brewski472001]

Is there a reason you didn’t post the most recent one?

Here's the most recent. I'm so glad you agreed that it was battery failure. This one happens at about 47% down to zero in a millisecond. Just out of curiosity, how do you open the file when it comes through in text form?? Thanks again.

 

[Brewski472001]

Here's the most recent. I'm so glad you agreed that it was battery failure. This one happens at about 47% down to zero in a millisecond. Just out of curiosity, how do you open the file when it comes through in text form?? Thanks again.

Just a heads up. When I was flying last August, it was on the Oregon coast and the ambient temperature was about 62 degrees, so, I think the speed may have caused it to heat up. I was flying with a pretty swift tailwind and my speed, so it said, was up around 70 kmh. I don't know if that was an error, but that's what it said.

 

[Brewski472001]

Just a heads up. When I was flying last August, it was on the Oregon coast and the ambient temperature was about 62 degrees, so, I think the speed may have caused it to heat up. I was flying with a pretty swift tailwind and my speed, so it said, was up around 70 kmh. I don't know if that was an error, but that's what it said.

Mistake. The 70 was on another flight. That flight didn't top 20.

 

[Brewski472001]

Mistake. The 70 was on another flight. That flight didn't top 20.

Also, it took me a while to figure out the first one to post. I got busy with something else and didn't get around to posting the latest. I also wanted to make sure that I sent what you needed.

 

[brett8883]

Here's the most recent. I'm so glad you agreed that it was battery failure. This one happens at about 47% down to zero in a millisecond. Just out of curiosity, how do you open the file when it comes through in text form?? Thanks again.

CsvView/DatCon

Same issue this time the temperature wasnt out of control but this seems like only the end of the flight can you post the one before that too.

Also how you treating your batteries?

 

[Brewski472001]

CsvView/DatCon

Same issue this time the temperature wasnt out of control but this seems like only the end of the flight can you post the one before that too.

Also how you treating your batteries?

I'll have to get back to you tomorrow Brett. Too much going on before bed. Thanks again.

 

[hewo]

brett, how come the battery glitched?
If boiled down to intelligent flight battery soft digitsl stowed data corruption then it is warrantable since
Why should repositories of precious firmware which boils down to safety, be jeopardized by chip repository that flakiness behaves?
Dont you believe ABSOLUTE dedication of firmware preserve is NEEDED?

 

[brett8883]

brett, how come the battery glitched?
If boiled down to intelligent flight battery soft digitsl stowed data corruption then it is warrantable since
Why should repositories of precious firmware which boils down to safety, be jeopardized by chip repository that flakiness behaves?
Dont you believe ABSOLUTE dedication of firmware preserve is NEEDED?

Ok so Ive had some time to look at it and I thought incorrectly at first that this was a partial flight. When you took off you it was showing only 50% something battery life but it was much worse than that. I do it sometimes too but I guess this why they say not to take off on partial batteries because immediately after take off the voltage dropped below what is advisable to fly with but the battery % doesn't doesnt reflect this change until later.


Theres alot going on here I know but the shaded regions are all low battery errors. The line I have highlighted is just before the percentage dips to 0% battery.

At this point all three cells are well below the danger level. You have two at 3.24v and the other at 2.82v. The battery percentage should never have shown this as 48%. The battery was giving a low battery error but shows 48% When you took off the cells where at about 3.5v which is much lower than would be advisable to take off with. Was showing 50 something% though.

Either this is a bad battery or your aircraft isnt interpreting what the battery is telling it I'm not sure.

I think we have to bring in the big guns to tell us what his opinion on this is because on one hand they do say not to take off with less then a full battery for exactly this reason, that the smart battery cant determine the percentage remaining as well but on the other you have a clearly broken cell that wasnt giving any errors I assume.

This one is above my pay grade @sar104 could you help us out please?

 

[WithTheBirds]

Ok so Ive had some time to look at it and I thought incorrectly at first that this was a partial flight. When you took off you it was showing only 50% something battery life but it was much worse than that. I do it sometimes too but I guess this why they say not to take off on partial batteries because immediately after take off the voltage dropped below what is advisable to fly with but the battery % doesn't doesnt reflect this change until later.
View attachment 72987

Theres alot going on here I know but the shaded regions are all low battery errors. The line I have highlighted is just before the percentage dips to 0% battery.

At this point all three cells are well below the danger level. You have two at 3.24v and the other at 2.82v. The battery percentage should never have shown this as 48%. The battery was giving a low battery error but shows 48% When you took off the cells where at about 3.5v which is much lower than would be advisable to take off with. Was showing 50 something% though.

Either this is a bad battery or your aircraft isnt interpreting what the battery is telling it I'm not sure.

I think we have to bring in the big guns to tell us what his opinion on this is because on one hand they do say not to take off with less then a full battery for exactly this reason, that the smart battery cant determine the percentage remaining as well but on the other you have a clearly broken cell that wasnt giving any errors I assume.

This one is above my pay grade @sar104 could you help us out please?

it is common to experience this outcome with a battery that has entered self discharge. The self discharge function simply switches the resistors which are used to bleed off cells and perform balancing during charge into circuit with the individual cells. The resistors are 10% value tolerance from rated value so it would be a fluke if you managed to get each cell discharged evenly. Charging will bring them into balance however flying without charging is a recipe for disaster. The cells at lower voltage supply the greatest share of the current in flight quickly draining. As is evidenced in your analysis.

 

[Arce101]

September 2018. Flying over ocean in Oregon, battery at 42% suddenly 0% battery in a millisecond, force landing alert and MA lands in two feet of saltwater and sand. Used my DJI refresh and had a brand new MA sent with replacement battery. Even though this was NOT pilot error, as I needed the aircraft to log my vacation and keep the wife happy that I shelled out a grand for this thing. (Did get some very nice vids and stills, so I'm still married) Fast forward to last weekend. Flying in Lake Tahoe, 47% battery, suddenly 0% battery, same scenario. Force landing, etc. Luckily soft landing into some pine boughs about 200" away from home, 5' off the ground. Talked to DJI and was told to send unit with all 3 batteries and controller. Of course, I synced all flight logs, etc. Just received an invoice to replace a flight board due to impact on MA. WHAT?????? This was NOT pilot error! I have been flying for over two years and know my way around flying, not to mention real aircraft! I am appalled that DJI has the nerve to present me with a repair bill. The logs CLEARLY show this being an aircraft error. I'm quickly losing faith in DJI and their products. Good luck to you all if this should happen to you.

What was the bill if you don’t mind me asking? I just recently sent mine in and I’m waiting on a response it gets to dji tomorrow and I’ll keep you posted on what they say.also when you sent the drone was it operational flying normally? Mine fell in about 2 feet of fresh water and I was getting imu errors also but I let it dry out for a couple days and everything went back to normal my gimbal is just messed up I get an overload error and it won’t pan up or down but the zoom works I hope the bill isn’t too much that’s why I’m asking what their chargeing you so I can get an idea

 

[sar104]

Both events resulted from one battery cell dropping to a critically low level:





The first flight was started at 94% battery, so possibly self-discharge had started. It's fairly quickly apparent that one cell is dropping faster, especially under higher current demand. The second flight starts at 52% battery, but it's not clear whether that's due to self-discharge or a previous flight.

If these batteries were flown after self-discharge had occurred then it's hard to say whether they are good or bad since, as pointed out above, unbalanced cells can exhibit this kind of behavior.

 

[PhantomFandom]

The first flight was started at 94% battery, so possibly self-discharge had started. It's fairly quickly apparent that one cell is dropping faster, especially under higher current demand. The second flight starts at 52% battery, but it's not clear whether that's due to self-discharge or a previous flight.

That was the first question I asked the OP and he stated that he always starts at 100%. Question would be what warnings were displayed in DJI Go4 when the voltages started to drop. Was there enough time to bring it in before total failure?

It should be covered under warranty! And Yes, I always fly with 100% battery at the start.

 

[sar104]

That was the first question I asked the OP and he stated that he always starts at 100%. Question would be what warnings were displayed in DJI Go4 when the voltages started to drop. Was there enough time to bring it in before total failure?

Both times the voltage triggered forced landing. In the first flight the warnings started about one minute before that happened, but the aircraft was around 300 m away fighting a headwind. On the second flight the problem developed faster.

 

[Deleted member 94047]

I always try to learn something from every crash postmortem that happens here and I think there is much to learn from this one as well. It seems to me that having the battery voltage displayed in the dji go4 app home screen would make one aware of the problem more quickly and possibly allow for remedial action to be taken much quicker. I googled if there was a way to do this and what I learned is that this is indeed possible with the Mavic twos but not with the Mavic Air. However, there is some who say it is possible with the Mavic Air too but only when using apple devices. Is there a definitive answer to this? I myself use an android phone and would certainly like to have this option enabled (if possible).

As always, thank you for the OP for sharing their logs and bringing this in to attention. And thank you flight analysis experts for digging in to the data to figure out what happened and why. We all learn from every crash shared and analyzed here. To the OP, I wish you the best of luck in your dealings with DJI, I hope they will reconsider their stance in light of the evidence presented here (assuming you were not flying with batteries that have been sitting idle for 10 days or so).

 

[BigAl07]

I think it's VERY important for people to realize that once the Auto-Discharge process starts the batteries should be considered "UnReliable" for flight until they are recharged to full capacity. Until that time they are most likely unbalanced and putting a heavy load on them will only exasperate the issue. Also being out of balance will most likely give erroneous "Average Voltage" readings in the app unless you're actively monitoring individual Cell Voltage.

 

[PhantomFandom]

I always try to learn something from every crash postmortem that happens here and I think there is much to learn from this one as well. It seems to me that having the battery voltage displayed in the dji go4 app home screen would make one aware of the problem more quickly and possibly allow for remedial action to be taken much quicker. I googled if there was a way to do this and what I learned is that this is indeed possible with the Mavic twos but not with the Mavic Air. However, there is some who say it is possible with the Mavic Air too but only when using apple devices. Is there a definitive answer to this? I myself use an android phone and would certainly like to have this option enabled (if possible).

As always, thank you for the OP for sharing their logs and bringing this in to attention. And thank you flight analysis experts for digging in to the data to figure out what happened and why. We all learn from every crash shared and analyzed here. To the OP, I wish you the best of luck in your dealings with DJI, I hope they will reconsider their stance in light of the evidence presented here (assuming you were not flying with batteries that have been sitting idle for 10 days or so).

Yes there are always learning experiences. In this case I see a few things to learn:

• Never, ever, ever start a flight with a battery that is less than 100%. No exceptions.
• Pay close attention to the battery voltage and battery percentage in the app. Don' push it. If you get a warning, immediately take action.
• If at all possible always fly upwind first, so that the return home is downwind and easier.

As to your question about battery voltage on the screen:

• I always like to have the battery voltage displayed up in the corner right next to the percentage.
• I use only Android devices and don't think I've ever had an issue enabling it on any of my drones. I can't confirm right now but I don't remember ever having an issue doing so on my Mavic Air. I could be wrong.
• Don't depend too much on that battery voltage being totally accurate since it is still not showing you the individual cells.

 

[Deleted member 94047]

I will check later if the option to have the battery voltage displayed on the home screen is available with the mavic air, but I don't remember ever seeing that option.

Edit: This seems to be a little mystery. Is it possible? Is it not?

Battery voltage display

Am I able to display voltage on the flight screen like the MP? Any help is appreciated.

mavicpilots.com

 

[offtheback]

Dont give up with DJI. Try to calmly explain the situation,. It might take a few different conversations for you to get satisfaction. Dont pay the bill quite yet

If you need help dealing with them, let me know. I have them on speed dial.

On speed dial?How do you keep your sanity?

 

[pfgrimm]

September 2018. Flying over ocean in Oregon, battery at 42% suddenly 0% battery in a millisecond, force landing alert and MA lands in two feet of saltwater and sand. Used my DJI refresh and had a brand new MA sent with replacement battery. Even though this was NOT pilot error, as I needed the aircraft to log my vacation and keep the wife happy that I shelled out a grand for this thing. (Did get some very nice vids and stills, so I'm still married) Fast forward to last weekend. Flying in Lake Tahoe, 47% battery, suddenly 0% battery, same scenario. Force landing, etc. Luckily soft landing into some pine boughs about 200" away from home, 5' off the ground. Talked to DJI and was told to send unit with all 3 batteries and controller. Of course, I synced all flight logs, etc. Just received an invoice to replace a flight board due to impact on MA. WHAT?????? This was NOT pilot error! I have been flying for over two years and know my way around flying, not to mention real aircraft! I am appalled that DJI has the nerve to present me with a repair bill. The logs CLEARLY show this being an aircraft error. I'm quickly losing faith in DJI and their products. Good luck to you all if this should happen to you.

Everyone upset with DJI (me too) should bear in mind that the PRC team let $150M wander off their premise. DJI policy, in general, seems to reflect their need to restore positive cash flow, quickly before net WC goes negative and DJI is no longer a going concern.
And to all who are genuinely [Language removed by Admin] off at DJI's general policy (me included), kindly think of what life would be like with American made camera products (REALLY).
I don't intend to start a controversy, but, all that said, I support the PRC tariffs. Among other long term benefits (to all), PRC companies must improve their fickle corporate governance to prevent gross embezzlement and other internal fraud that ends up costing us (the camera consumer) more money due to DJI's incompetence. There's more to running a biz than great engineering and world-class products. Enough said...