I was flying my brand new (2 day old) Mavic back home after a 15 minute flight, because the battery level was getting low. The battery was fully charged before the flight, and had discharged from 100% to 20%, in about 15 minutes (~5% per minute). I was cutting it close to get back, but thought 20% meant I had about four minutes of flight time left to get home. All of a sudden, my battery level started dropping like a rock. It discharged from 20% to 0% in about 20 seconds, and my Mavic fell out of the air and into the water that I was flying over.
I contacted DJI support and was shocked to be told there was nothing they could do because I wasn't running DJI Go, apparently because that is the only place flight logs are kept.

I've been flying drones for years, but this is my first DJI drone. All the other drones I've owned keep "black box" logs in the controller. As the Mavic controller has "Black Box" logs, I assumed that was sufficient should I need support.

Now, it looks like I'm out $1000 due to a battery failure, and DJI is basically saying "tough luck" because apparrently, I should have been using a 3rd party device to keep the logs. I was able to graph the battery level from the controller logs, and it clearly shows a "drop off a cliff" discharge rate once the battery hit 20%. (Which shows the battery was still connected, and sending charge level data up until the end)

Is there anything I can do? Where is the small print that flying without DJI Go voids the warranty?

I predict you will be torn up in here because 1) you were flying over water with only 20% battery, 2) you didn't read up sufficiently on your new DJI drone to learn where the 'black box', as you put it, is, and 3) your story has been in these forums before..  Let's see what happens next.

Tombolian Posted at 2017-6-19 08:21
I predict you will be torn up in here because 1) you were flying over water with only 20% battery, 2) you didn't read up sufficiently on your new DJI drone to learn where the 'black box', as you put it, is, and 3) your story has been in these forums before..  Let's see what happens next.

It will be interesting to see how the community responds.

I did spent quite a bit of time reading the doc, and making sure I could download logs from the Mavic and the controller using DJI Assistant 2. IMy oversight was that I must have missed the documentation that said that the controller logs were useless for flight diagnostics.

I'm curious why the controller even lets you take off without a connected device, if doing so essentially voids your warranty. It would at least be nice to have some sort of necessary override to warn new users that they were flying "warrantyless" when they did so.

DocDNA Posted at 2017-6-19 08:28
It will be interesting to see how the community responds.

I did spent quite a bit of time reading the doc, and making sure I could download logs from the Mavic and the controller using DJI Assistant 2. IMy oversight was that I must have missed the documentation that said that the controller logs were useless for flight diagnostics.

Also, what is the recommended battery level to fly over water, if the percentage remaining can drop to zero at any time? I'm not saying I intended to be still over the water at 20%, but accidents happen, and it's nice if your battery doesn't "drop out" from underneath you when you get in that situation.

First of all, I'm sorry you lost your Mavic.  The local logs are not in the controller, but in the DJI Go 4 app.  Although this is only a partial log, it may contain some useful information. Posting that information to PhantomHelp will be a start to analyzing your problem

If you read many of the "lost Mavic" cases posted to the forum,  you'll soon recognize the questions you'll likely be asked.  
Like:
  - where was you battery threshold set for automatic RTH?
  - was there a strong headwind on your return leg?
  - what warnings did you receive?

Some of these questions can be answered by posting your log.  So that's the first step.

Hi 147a1bdd, if you upload your flight log from your app to http://www.phantomhelp.com/LogViewer/Upload/

Some here will take a look at your log and might be able to give you a better understanding as to what might have happened, don't pay any attention to what tombolian said you won't be thorn to shreds. There are many here who will try to help. Griffith has given you some idea of what can be found out.

Regards to your warranty yes you might have a problem there, if your malfunction or crash was caused by using third party app then warranty won't apply, you might need to try to prove this is not the case but with only limited logs this could be difficult.

Griffith Posted at 2017-6-19 10:02
First of all, I'm sorry you lost your Mavic.  The local logs are not in the controller, but in the DJI Go 4 app.  Although this is only a partial log, it may contain some useful information. Posting that information to PhantomHelp will be a start to analyzing your problem

If you read many of the "lost Mavic" cases posted to the forum,  you'll soon recognize the questions you'll likely be asked.  

The whole problem here is that I wasn't running the DJI Go App, and didn't realize I was required to be running it to get support.

So, you were just flying with the RC?  

DocDNA Posted at 2017-6-19 11:06
The whole problem here is that I wasn't running the DJI Go App, and didn't realize I was required to be running it to get support.

You warranty will still be honored if the crash was clearly caused by the aircraft itself.

DocDNA Posted at 2017-6-19 08:28
It will be interesting to see how the community responds.

I did spent quite a bit of time reading the doc, and making sure I could download logs from the Mavic and the controller using DJI Assistant 2. IMy oversight was that I must have missed the documentation that said that the controller logs were useless for flight diagnostics.

My oversight was that I must have missed the documentation that said that the controller logs were useless for flight diagnostics.


They're not useless, they just don't contain the detail of the Mavic DAT files which are often required to diagnose certain problems.  Some problems actually can be resolved with DJI GO LOG files.

I presume you were not able to recover the water-logged Mavic.  Unfortunately for you, the Mavic files or the GO files are the your only possibility for providing evidence of a hardware problem.

DocDNA Posted at 2017-6-19 11:06
The whole problem here is that I wasn't running the DJI Go App, and didn't realize I was required to be running it to get support.

Are you saying you have no logs, how did you get all the information about your battery?

hallmark007 Posted at 2017-6-19 12:04
Are you saying you have no logs, how did you get all the information about your battery?

Good question. I downloaded the blackbox files from the controller using DJI Assistant 2.  I found some scripts to extract the data into a readable format, and among other things, there was data on battery level along with timestamps. There are a few other pieces of information in there as well, but I guess not as much as would be in the DJI Go logs.

When I chatted with DJI support, and they told me there was nothing they could do without the DJI Go logs.
Here's what I have though... you can see the dropoff once it hits around 20 percent...

DJI Joe Posted at 2017-6-19 11:15
You warranty will still be honored if the crash was clearly caused by the aircraft itself.

Well, once I told DJI support chat that I didn' have DJI Go logs, they told me they "couldn't help me", but they were "Sorry that I lost my Mavic".

DocDNA Posted at 2017-6-19 13:27
Good question. I downloaded the blackbox files from the controller using DJI Assistant 2.  I found some scripts to extract the data into a readable format, and among other things, there was data on battery level along with timestamps. There are a few other pieces of information in there as well, but I guess not as much as would be in the DJI Go logs.

When I chatted with DJI support, and they told me there was nothing they could do without the DJI Go logs.

I don't know how much information you have got or have given to dji but I think you should pursue the matter until they read your information or see if they would agree to giving you a discount on your two day old Mavic .

Griffith Posted at 2017-6-19 11:11
So, you were just flying with the RC?

I was flying with the RC and Litchi. Unfortunately, it looks like Litchi didn't log any data. (It saw mention of CSV files, but couldn't find any)

Not that it seemed to make a difference. DJI support told me that no DJI Go means no help if your Mavic goes down. They didn't even ask if I was using another app.

Griffith Posted at 2017-6-19 11:28
I presume you were not able to recover the water-logged Mavic.  Unfortunately for you, the Mavic files or the GO files are the your only possibility for providing evidence of a hardware problem.

No, actually, I have some decent evidence of the problem from the RC black box. I also have altitude data, speed, distance, etc.

The big problem is that it appears that even though the RC logs some useful data, that DJI only wants to see the data from DJI Go.

I could go on for hours with all the mistakes you made with your Mavic.

I Agree with DJI, fly at YOUR own risk if you choose to fly 3rd party.

DocDNA Posted at 2017-6-19 13:33
I was flying with the RC and Litchi. Unfortunately, it looks like Litchi didn't log any data. (It saw mention of CSV files, but couldn't find any)

Not that it seemed to make a difference. DJI support told me that no DJI Go means no help if your Mavic goes down. They didn't even ask if I was using another app.

Are litch logs not logged through airdata?

fans2e9aa3da Posted at 2017-6-19 13:46
I could go on for hours with all the mistakes you made with your Mavic.

I'm all ears. I'm interested to see how a brief statement about my Mavic dropping into the water can translate into going on for hours about all of the mistakes I've made. But at least I figured out how to change my default handle. ;)

hallmark007 Posted at 2017-6-19 14:10
Are litch logs not logged through airdata?

It looks like I had my Litchi logging turned off. Duh!

Sime Posted at 2017-6-19 13:59
I Agree with DJI, fly at YOUR own risk if you choose to fly 3rd party.

Actually, if you read me above posts, you'll realize this is the complete opposite situation. My mistaken assumption was that if I was using all first party devices (DJI RC and Mavic) that I would be covered. Instead, I needed to have a third party device (an Android phone) connected to my controller to provide logging functions that I thought would be covered by a first party device (the RC) like all of the other UAV platforms I've used.

DJI support never asked or never knew that I was running Litchi. All they had to know was that I didn't have a third party device (my android phone) connected to the RC and running DJI Go.

DocDNA Posted at 2017-6-19 14:38
I'm all ears. I'm interested to see how a brief statement about my Mavic dropping into the water can translate into going on for hours about all of the mistakes I've made. But at least I figured out how to change my default handle. ;)

Well for starters this is your first DJI which tells me you know jack about intelligent batteries, they can take a number of cycles to realise full capacity and flight time and try not to fully discharge a new pack for the first few cycles, ideally don't discharge a new pack below 50% for the first 10 cycles.
Secondly before you knew how long the batteries would actually last you were over water with only 20% left.
You may have been flying drones for years but you haven't flown this drone for years and ever one different. And just because you have been doing something for a long time doesn't mean your good at it.
Do you figured out how to change your name. Maybe you should have figured out how to fly your Mavic.

hallmark007 Posted at 2017-6-19 14:10
Are litch logs not logged through airdata?

Not automatically, but there's a function within Litchi that allows you upload your Litchi logs to AirData.

DocDNA Posted at 2017-6-19 14:39
It looks like I had my Litchi logging turned off. Duh!

I doubt that; in fact, I don't even know of a way to turn off the logging of a flight in Litchi. You probably just need to create an AirData account, then go into the Litchi app and tell it to synchronize (upload) your flight logs. Once that's done you'll be able to find the log for your last flight on AirData and post a link to it here.

Sime Posted at 2017-6-19 13:59
I Agree with DJI, fly at YOUR own risk if you choose to fly 3rd party.

Read the answers before giving your professional assessment...

My guess is that it is an intelligent battery that keeps track of charging/discharging behaviour (which changes over time). Being a brand new drone it might not have learned the low limit yet.

FlyingSmasher Posted at 2017-6-19 18:13
So you know a lot of JACKS???

Don't have anything to contribute to the solution then go find some more JACKS

new lipo's WILL do that.... they also need a couple of cycles (as mentioned, 10 is mostly a safe number) to get to their full potential. After that the discharge rate and curve is optimal....

fans2e9aa3da Posted at 2017-6-19 16:56
Well for starters this is your first DJI which tells me you know jack about intelligent batteries, they can take a number of cycles to realise full capacity and flight time and try not to fully discharge a new pack for the first few cycles, ideally don't discharge a new pack below 50% for the first 10 cycles.
Secondly before you knew how long the batteries would actually last you were over water with only 20% left.
You may have been flying drones for years but you haven't flown this drone for years and ever one different. And just because you have been doing something for a long time doesn't mean your good at it.

Well, i shouldn't be feeding the trolls, but I'll bite.

First, you do realize that other UAV's use intelligent batteries, right? So, what makes you think i don't have experience with those types of batteries?

Second, where did I say how many charge cycles were on the battery before the problem occurred?

There's a lot of speculation based on limited info going on here. This was the 17th charge cycle on the battery, and FWIW, there were other long flights included in those cycles.

DroneFlying Posted at 2017-6-19 17:09
I doubt that; in fact, I don't even know of a way to turn off the logging of a flight in Litchi. You probably just need to create an AirData account, then go into the Litchi app and tell it to synchronize (upload) your flight logs. Once that's done you'll be able to find the log for your last flight on AirData and post a link to it here.

The option to turn off logging is one the Aircraft tab in options. But regardless, DJI has stated that its DJI Go, or "no go" for warranty support.

DocDNA Posted at 2017-6-20 01:21
The option to turn off logging is one the Aircraft tab in options. But regardless, DJI has stated that its DJI Go, or "no go" for warranty support.

I'm looking at it right now and don't have an option to turn off logging. Are you referring to the option to disable syncing with AirData, which is off by default? If so, that doesn't disable logging of your flights.

DocDNA Posted at 2017-6-20 01:22
There's a lot of speculation based on limited info going on here. This was the 17th charge cycle on the battery, and FWIW, there were other long flights included in those cycles.

17 charges on a two day old battery?

Watty2000 Posted at 2017-6-20 02:40
17 charges on a two day old battery?

Yep. I got the drone on Friday, and dropped it into the water on Sunday afternoon.

DroneFlying Posted at 2017-6-20 02:14
I'm looking at it right now and don't have an option to turn off logging. Are you referring to the option to disable syncing with AirData, which is off by default? If so, that doesn't disable logging of your flights.

Nooe, right below calibrate compass on the aircraft tab, is a "log flights" option. It's a couple of spots above the "airdata UAV automatic sync" option.

fans2e9aa3da Posted at 2017-6-20 02:31
17 cycles on a 2day old battery! Not likely. You are a fool. With every post you give yourself a little more rope to hang your self.

Consider me hung, Sherlock.

DocDNA Posted at 2017-6-20 03:44
Nooe, right below calibrate compass on the aircraft tab, is a "log flights" option. It's a couple of spots above the "airdata UAV automatic sync" option.

That isn't available on the version of Litchi I have / use (1.16.2 on iOS); "Calibrate Compass" is the last setting / action available in the "Aircraft" section and is followed immediately by the "Camera" section. What Litchi version and OS are you using and would you mind providing a screen capture of what the options look like for you? This is the first I can remember hearing of Litchi allowing a user not to log their flights.