Get more from your Mavic
The largest Mavic community in the world
Join Us Now

Mavic Air critical failure

Baseballfan

Member
Joined
Feb 17, 2019
Messages
6
Reactions
7
Location
Richmond, VA
Visit site
I had a failure today when I was out flying I had over half the battery left when all of a sudden the battery went dead. I tried to get to get it to land on the road but unfortunately it landed in a tree where I am not able to get to it I was wondering if someone could read them and see if it was a critical failure so I can upload it to them and see if they would replace it. Thanks for all the help!
 

Attachments

  • 2020-11-14 15_06_12-0K12F9M00S0399.dat
    1.2 KB · Views: 8

slup

Well-Known Member
Joined
Oct 18, 2019
Messages
1,430
Reactions
1,680
Age
52
Location
Sweden
Visit site
Hi there & welcome to the forum 👋 :D ... sorry it's due to these circumstances though.

You had a battery cell failure in cell 2 ... already from the beginning of the flight cell 2 deviated major from cell 1 & 3. At 163sec into the flight you got the first warning in the app saying "Battery power limit will automatically reduce the aircraft's mobility to ensure flight safety" ... this after pushing the MA1 full in Sport mode.

Below in the chart you find the relevant data for this ... as seen by the blue graph (cell 2 voltage) it degrades major by your commanded speed (grey graph). At 199sec (where I have placed the markers in the chart) the voltage level in cell 2 is as low as 2,61V (below 3V it sustain permanent damage & Force landing will follow). The battery is from June 2018 ... & it's unknown how you have treated it (charge cycles, storage charge etc.) The battery warranty is usually 6 month ... so going for a warranty case towards DJI will be really hard.

(Click on the chart to make it larger)
1605442092198.png
 
  • Like
Reactions: Thomas B

Baseballfan

Member
Joined
Feb 17, 2019
Messages
6
Reactions
7
Location
Richmond, VA
Visit site
Thank you so much for looking into. I bought the drone in January of last year so for sure the battery is no longer in warranty. When I use them I would use them from full to like 35% percent left unfortunately I had only used each of the 3 batteries I had only like 10 times so it there weren't used very much but thank you so much again for looking into. I am going to go out there today and see if I can fish it out of the tree or we are having some wind maybe that pushed it out since it was on the end part of a branch. It didn't land in the main trunk or closer in on the branch so the little branches are kind of cradling it. I will post back on here if I got it back or not.
 
  • Like
Reactions: hiflyer201 and slup

boblui

Well-Known Member
Joined
May 11, 2020
Messages
1,024
Reactions
865
Location
Hong Kong
Visit site
This is the voltage change of the battery of my M2P from 100% to 0% battery. You can see two things :

1) The voltage difference between cells is never more than 0.02V
2) The cell voltage drops to 3.58 V when the battery level reaches 0%

1605446634023.png

Your battery exhibited something totally different :

1) The voltage difference between cells was more than 0.1V sometimes even if the problemetic cell ( #2 ) is ignored.
2) The cell voltage dropped below 3.58 V when the reported battery level was as much as 80%.

It looks like all the cells are bad with cell #2 being the worst. Furthermore, the calibration of the battery was wayyyyy off . To maximize the life of the battery and ensure proper calibration, it is essential to :

1) store the battery at 30% ~ 40% charge level
2) store the battery at cool places. high temperature kills.
3) fully discharge the battery once every 3 months. This is to ensure that the reported % battery figure keeps being accurate.

1605446490376.png
 
Last edited:

Baseballfan

Member
Joined
Feb 17, 2019
Messages
6
Reactions
7
Location
Richmond, VA
Visit site
I let them auto discharge is that a bad thing and how do you charge them to 30-40%? I have other chargers for planes that let you charge them up to storage voltage but DJI do all or nothing? Do I just let them charge up to 1 dot then take them off the charger just not quite understanding.
 

slup

Well-Known Member
Joined
Oct 18, 2019
Messages
1,430
Reactions
1,680
Age
52
Location
Sweden
Visit site
I let them auto discharge is that a bad thing and how do you charge them to 30-40%? I have other chargers for planes that let you charge them up to storage voltage but DJI do all or nothing? Do I just let them charge up to 1 dot then take them off the charger just not quite understanding.
To let the MA1 batteries auto discharge takes 10 days ... if you doesn't push the button on the battery, doing that will reset the 10 day counter. To have the batteries above or below storage % (30-60%) longer than approx 2 days isn't good for them ... the 10 day auto discharge is too long actually. Charge them up the evening before or the day you will be flying, fly them down no lower than approx 15-20 %, then let them cool to room temperature & charge up to storage. If you doesn't have a charger that stops at storage levels then monitor the batteries & take them off the charger between 1 led solid & one blinking up to 2 solid & one blinking. You can go for a aftermarket charger with storage mode ... I have this which have worked flawless --> https://www.amazon.com/Hanatora-Battery-Controller-Charging-Discharging/dp/B07ZV44415 ... this one also charge all 4 batteries in parallel, so in an hour I have all 4 + the remote fully charged.

1605453439114.png
 

boblui

Well-Known Member
Joined
May 11, 2020
Messages
1,024
Reactions
865
Location
Hong Kong
Visit site
I let them auto discharge is that a bad thing and how do you charge them to 30-40%? I have other chargers for planes that let you charge them up to storage voltage but DJI do all or nothing? Do I just let them charge up to 1 dot then take them off the charger just not quite understanding.

For my M2P, I just charge it to 1 solid light + 1 blinking light on the battery. Of course if I finish flying with around 30% battery left, I don't need to do anything. If I have a lot left, I discharge it with an USB LED lamp by connecting it to the battery via the USB adaptor that came with the combo kit.

BTW the recommended 30 ~ 40% charge level for storage came from this reference ( 3.7V corresponds to 30% charge level ). I am not sure why DJI battery auto-discharges to 60% :

1605470383801.png
 
Last edited:

kidroc

Well-Known Member
Joined
Aug 21, 2017
Messages
840
Reactions
352
Age
44
Visit site
Thank you so much for looking into. I bought the drone in January of last year so for sure the battery is no longer in warranty. When I use them I would use them from full to like 35% percent left unfortunately I had only used each of the 3 batteries I had only like 10 times so it there weren't used very much but thank you so much again for looking into. I am going to go out there today and see if I can fish it out of the tree or we are having some wind maybe that pushed it out since it was on the end part of a branch. It didn't land in the main trunk or closer in on the branch so the little branches are kind of cradling it. I will post back on here if I got it back or not.
Not using them doesn’t make last any longer batts like to be used. It’s hard to find time sometimes to go fly but letting them set for a year is not great for a lipo.