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Battery dropped from 53% to 0% ,almost lost my MA

RayOZ

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@sar104 could you add the speed/throttle in the graph. is it occurring at max power? the large voltage drops, especially in sport mode, might be corresponding to power draw from motors.
 

laurens23

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That would make sense and Dji must be thinking the same as they asked me to run the batteries down to 8% and recharge in hope it might recalibrate the batteries.
That (deep-cycle) is actually a common process to "recalibrate" the battery capacity. The Xiaomi mi 4k drone actually gives a message to do a full discharge after x cycles. (i.e. leave it on after a flight until it turns off by itself, and then charge to full. This will then reset the battery capacity value)

It however does not explain what happened to your battery.
 

laurens23

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@sar104 could you add the speed/throttle in the graph. is it occurring at max power? the large voltage drops, especially in sport mode, might be corresponding to power draw from motors.
I already checked, and see nothing unusual with the throttle or speed. I looked at the logs for any anomalies in other metrics at the time the battery % drops to 0. The only one I found with a clear relation was the FullCapacity.
 

RayOZ

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I already checked, and see nothing unusual with the throttle or speed. I looked at the logs for any anomalies in other metrics at the time the battery % drops to 0. The only one I found with a clear relation was the FullCapacity.
i was thinking along the line; full throttle -> higher speed -> larger voltage drop -> smart battery mistaken as sudden drop in capacity -> trigger low battery
 

laurens23

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i was thinking along the line; full throttle -> higher speed -> larger voltage drop -> smart battery mistaken as sudden drop in capacity -> trigger low battery
yes, that was one of the first things I checked for :) Below the plot of the throttle and current (current is more relevant then speed, and the voltage is already posted by Sar). as you can see there is no abnormality at the moment the issue occurs (the other logs also show no abnormality in the throttle or current)


 

Kevjones777

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There is nothing on that aircraft other than a direct short that could possibly drop the voltage from 50 odd percent to 0 in 3 seconds. The aircraft would fry itself and the battery would probably explode or catch fire. Plus we know it never happened. It did not actually go to 0 it only said it did. This points more and more to a Firmware calibration error or a value left behind in a register that for some reason is not being correctly reported. The most weird thing is it's only on some batteries in some aircraft.
 

hquant

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I had a very similar experience. From 30% to nothing in about 60 Seconds. I was lucky that I had my battery warning unchanged at 30% when it went off. I moved away from the landing pad a bit to test precision landing, about 100 ft. Then I activated RTH and the Air went up to about 100 ft and started to land. All of a sudden, the critical battery warning sounded and I went to manual to put the drone down fast. When I looked a the battery status after landing it showed 0%. Moreover the battery would not charge any more. The loading dock went from a green light to a red light within 10 seconds and the smart battery's LEDs remaind dark. I sent the battery to the DJI Service and today received a message that they swapped it for a new battery free of charge and that it's on the way back to me.
I never discharged the battery below 20% and I have used each battery probably 4-5 times. Had I set my battery alarm to 20% i would very likely have crashed the drone due to power failure.
 
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laurens23

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I had a very similar experience. From 30% to nothing in about 60 Seconds. I was lucky that I had my battery warning unchanged at 30% when it went off. I moved away from the landing pad a bit to test precision landing, about 100 ft. Then I activated RTH and the Air went up to about 100 ft and started to land. All of a sudden, the critical battery warning sounded and I went to manual to put the drone down fast. When I looked a the battery status after landing it showed 0%. Moreover the battery would not charge any more. The loading dock went from a green light to a red light within 10 seconds and the smart battery's LEDs remaind dark. I sent the battery to the DJI Service and today received a message that they swapped it for a new battery free of charge and that it's on the way back to me.
I never discharged the battery below 20% and I have used each battery probably 4-5 times. Had I set my battery alarm to 20% i would very likely have crashed the drone due to power failure.
that sounds more like an actual defect/issue with the battery cells. But if you want you can post the logs so we can compare them to the issue in this threat.
 

Poundofnuts

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Hi,I got a MA on Tuesday. I spent a few days reading through the instructions,charging,updating and just getting to know my new toy.i took it out on Friday morning to give it a test and the strangest thing happened. I was flying around at around 53% then suddenly the battery went to 0% and started to land,controller kept disconnecting.i started running over the field to get to it,I managed to land it safely. The battery appeared flat on the led indicator on the battery. So I decided to try my second battery and the same happened around the same battery percentage.
So I uploaded the flight records to air data. Everything seems to be ok till it happens. This isn’t my first Dji product,I had a phantom 3 advanced so I don’t think I’ve made any silly mistakes. Started the flight at 100% ,calibrated the compass ,connected to gps ,phone charged,weather was pretty calm 5deg,home point set . Seen this issue a few times on the Dji forum but nobody seems to have an idea. I don’t really think it’s a battery issue,or I could be really unlucky and have two bad batteries. Please take a look at my flight logs an see if I’ve missed anything. Seems like software issue but can’t really prove it.
Thanks

Airdata UAV - Flight Data Analysis for Drones

Airdata UAV - Flight Data Analysis for Drones
Hi,I got a MA on Tuesday. I spent a few days reading through the instructions,charging,updating and just getting to know my new toy.i took it out on Friday morning to give it a test and the strangest thing happened. I was flying around at around 53% then suddenly the battery went to 0% and started to land,controller kept disconnecting.i started running over the field to get to it,I managed to land it safely. The battery appeared flat on the led indicator on the battery. So I decided to try my second battery and the same happened around the same battery percentage.
So I uploaded the flight records to air data. Everything seems to be ok till it happens. This isn’t my first Dji product,I had a phantom 3 advanced so I don’t think I’ve made any silly mistakes. Started the flight at 100% ,calibrated the compass ,connected to gps ,phone charged,weather was pretty calm 5deg,home point set . Seen this issue a few times on the Dji forum but nobody seems to have an idea. I don’t really think it’s a battery issue,or I could be really unlucky and have two bad batteries. Please take a look at my flight logs an see if I’ve missed anything. Seems like software issue but can’t really prove it.
Thanks

Airdata UAV - Flight Data Analysis for Drones
Hi,I got a MA on Tuesday. I spent a few days reading through the instructions,charging,updating and just getting to know my new toy.i took it out on Friday morning to give it a test and the strangest thing happened. I was flying around at around 53% then suddenly the battery went to 0% and started to land,controller kept disconnecting.i started running over the field to get to it,I managed to land it safely. The battery appeared flat on the led indicator on the battery. So I decided to try my second battery and the same happened around the same battery percentage.
So I uploaded the flight records to air data. Everything seems to be ok till it happens. This isn’t my first Dji product,I had a phantom 3 advanced so I don’t think I’ve made any silly mistakes. Started the flight at 100% ,calibrated the compass ,connected to gps ,phone charged,weather was pretty calm 5deg,home point set . Seen this issue a few times on the Dji forum but nobody seems to have an idea. I don’t really think it’s a battery issue,or I could be really unlucky and have two bad batteries. Please take a look at my flight logs an see if I’ve missed anything. Seems like software issue but can’t really prove it.
Thanks

Airdata UAV - Flight Data Analysis for Drones

Airdata UAV - Flight Data Analysis for Drones
Make sure you update each of your batteries after you update your drone. If not you will have issues. When the Mavic Air is updated, it updates the bird and the battery that is currently in the bird. You then need to power cycle everything and put in your second battery and update the firmware on the second battery, then do the same for the third battery and you shouldn’t have any issues.
 

Air Beetle

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So far, no one has mentioned a very important firmware update step that is likely the cause of your problems. A firmware update includes updates to the firmware in the batteries. After you update the Air, you have to reboot it with EACH battery and do the update again. DJI should include a pop up window to remind the pilot to repeat the update with each battery. It's not intuitive to think that each battery has firmware.

I'll bet if you insert each battery and check firmware, you will find out that the battery not up to date.
 

garethshaw

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This one is very simple. After 7 years of commercial flying, this is pilot error. At below 5C you shouldn’t have taken off. The chemical changes within the battery are only rated down to 5C and you were flying at 3.9C. That’s enough to cause 1 or more of the cells to fail, during that flight. the reason both batteries failed is because they both suffered the same issue.

Take off temp of 3.9 plus prop wash plus altitude equals failure.

Please do some more research into battery temperature ranges and don’t fly in temperatures so low. Only the inspire in the DJI range is rated for below 0C and only then with special heating systems.

Hope this helps.
Gareth

Hi,I got a MA on Tuesday. I spent a few days reading through the instructions,charging,updating and just getting to know my new toy.i took it out on Friday morning to give it a test and the strangest thing happened. I was flying around at around 53% then suddenly the battery went to 0% and started to land,controller kept disconnecting.i started running over the field to get to it,I managed to land it safely. The battery appeared flat on the led indicator on the battery. So I decided to try my second battery and the same happened around the same battery percentage.
So I uploaded the flight records to air data. Everything seems to be ok till it happens. This isn’t my first Dji product,I had a phantom 3 advanced so I don’t think I’ve made any silly mistakes. Started the flight at 100% ,calibrated the compass ,connected to gps ,phone charged,weather was pretty calm 5deg,home point set . Seen this issue a few times on the Dji forum but nobody seems to have an idea. I don’t really think it’s a battery issue,or I could be really unlucky and have two bad batteries. Please take a look at my flight logs an see if I’ve missed anything. Seems like software issue but can’t really prove it.
Thanks

Airdata UAV - Flight Data Analysis for Drones

Airdata UAV - Flight Data Analysis for Drones
 

Benmoore1234

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So far, no one has mentioned a very important firmware update step that is likely the cause of your problems. A firmware update includes updates to the firmware in the batteries. After you update the Air, you have to reboot it with EACH battery and do the update again. DJI should include a pop up window to remind the pilot to repeat the update with each battery. It's not intuitive to think that each battery has firmware.

I'll bet if you insert each battery and check firmware, you will find out that the battery not up to date.
Everything was up to date. Sorry you would have lost your bet
 

BudWalker

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This one is very simple. After 7 years of commercial flying, this is pilot error. At below 5C you shouldn’t have taken off. The chemical changes within the battery are only rated down to 5C and you were flying at 3.9C. That’s enough to cause 1 or more of the cells to fail, during that flight. the reason both batteries failed is because they both suffered the same issue.

Take off temp of 3.9 plus prop wash plus altitude equals failure.

Please do some more research into battery temperature ranges and don’t fly in temperatures so low. Only the inspire in the DJI range is rated for below 0C and only then with special heating systems.

Hope this helps.
Gareth
Is this relevant since the battery temp was 16.9° C at launch?
 
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Benmoore1234

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Also the cells didn’t fail. The ma was still flying. It was just the display on my phone that said it was o
 

Travisimo

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So far, no one has mentioned a very important firmware update step that is likely the cause of your problems. A firmware update includes updates to the firmware in the batteries. After you update the Air, you have to reboot it with EACH battery and do the update again. DJI should include a pop up window to remind the pilot to repeat the update with each battery. It's not intuitive to think that each battery has firmware.

I'll bet if you insert each battery and check firmware, you will find out that the battery not up to date.
The app does give you an "inconsistent firmware" message when you power on the aircraft with a different battery after having done a firmware update on the aircraft itself. The battery that is in the aircraft at the time you update the aircraft's firmware does get updated automatically, so you'll get the "inconsistent firmware" message after you put in a different battery and power on the aircraft, remote, and app.
 

DHFN

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This one is very simple. After 7 years of commercial flying, this is pilot error. At below 5C you shouldn’t have taken off. The chemical changes within the battery are only rated down to 5C and you were flying at 3.9C. That’s enough to cause 1 or more of the cells to fail, during that flight. the reason both batteries failed is because they both suffered the same issue.

Take off temp of 3.9 plus prop wash plus altitude equals failure.

Please do some more research into battery temperature ranges and don’t fly in temperatures so low. Only the inspire in the DJI range is rated for below 0C and only then with special heating systems.

Hope this helps.
Gareth
Pilot error is always an easy on. Gareth have you been reading through all the posts before this simple conclusion.
 
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Machineur

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Then again.
18% to 0% same battery.
For me i think it is the battery fault.
I have 4 battery i have made a test just fly over the pad and drain the 4 battery.
the same battery drop 18% to 0% and land on site. The 3 oders ask permition to land at 15%.