Battery continue to run below 0%
1056 10 2023-5-15
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djiuser_UOmYJok8Lpfl
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This is actually something I came across a few of DJI products. Including mavic pro 2 air 2 and mini 3 pro
The battery actually continues to run below 0 present and can fly for up to 1.40 minutes after indicating as 0 present.
After force landing if you bring the drone close to graund and mess with the downwards sensor it will ask to check if clear to land. And will not actually land until more than one minute which depending on wind I managed to get it to fly over 1.4 minutes.
It actually has the ability to fly and move around during that time.
Unlike mavic pro 2 witch would actually shutdown completely after the actual force landing. The mini 3 pro will stay powered on for a few minutes after the force landing (after a minute or more flying below 0%) and battery level on the monitor actually seems to have some life left in it.

All this begs the question. Why is force landing activated by 8 present when it can clearly fly for several minutes more. Or is the battery not calibrated correctly. Witch doesn't seem to be the case sins it happens again and again.

So I would think that DJI will say that it's purpose is protecting the battery life ect etc. But I'm pretty sure that the advertised 47 minutes of fly time most definitely includes this extra time hidden below 0%.
In edition. Instead of crash landing do to rth calculation inaccuracy (witch happened to me on the air 2) why not just inform the user that flying below so and so present can hurm the battery and give me the actual choice to use the product in the way it was advertised that it can work. And most definitely don't crash the drone 1000 ft away from the home point in to a tree only because it reached 8%
2023-5-15
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Sean-bumble-bee
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Whatever DJI do, some people will try to
a) "push the boundaries of the flight envelope" &
b ) blame DJI for problems that stems from bad piloting.
For example
1) flying out to distance downwind,
2) set inappropriate RTH heights - be that too low or so high that the drone is sent up into strong winds,
3) not knowing how a drone behaves in a particular set of circumstance e.g. the pilot has some horizontal and vertical control and possibly yaw control during forced landing i.e. they could use the camera to see threats and manoeuvre to avoid them.
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frankymusik
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Sean-bumble-bee Posted at 5-15 21:36
Whatever DJI do, some people will try to
a) "push the boundaries of the flight envelope" &
b ) blame DJI for problems that stems from bad piloting.

Very, very well summed up!  
Again and again the same problems and questions with the most different users...   
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djiuser_UOmYJok8Lpfl
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Sean-bumble-bee Posted at 5-15 21:36
Whatever DJI do, some people will try to
a) "push the boundaries of the flight envelope" &
b ) blame DJI for problems that stems from bad piloting.

Actually my specific case was do to 180 degree wind change and I accidentally manually triggered rth at 65%.
The trees was the safest option. I needed to choose between trees or risking falling on a busy highway.
And I'm steaming about the fact that it could actually reach the home point
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JJB*
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Interesting post....

But for battery health and for flight safety aim to land with 20 to 30% batttery level.So why make a problem of a non-problem ?

Do you fill up your car with 0.1 liter fuel left in the tank ?

About your 8% crash in trees....even with a forced battery landing you can fly in all directions until 0%, or less than 0%.
Good flight planning means that you will never be trapped in such situation.

47 minutes advertised is indeed form 100 to 0% in an optimum flight setting, so this flight time is never achieved in normal flights!  
More realistic form DJI would be flight time advertising from 100 to 20% battery level.

cheers
JJB
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djiuser_UOmYJok8Lpfl
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JJB* Posted at 5-15 23:14
Interesting post....

But for battery health and for flight safety aim to land with 20 to 30% batttery level.So why make a problem of a non-problem ?

You all are right that better flight planning would most likely prevent that case that actually happened a long time ago but that is not the point.
I will not drive my car with 2 litters of feul but I most definitely not want the car to stop at that point.
The point is that if the battery has about 4% left when indicating 0. It should not force landing at 8%
And I know that you can still fly in force landing but it is much more difficult to do so and you lose precious attitude that can save the day.
All I ask is for DJI to show the actual battery level. And at most to advise users about the consequences. And calculate force landing to be at a later point.
Is that to much to ask?
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DAFlys
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djiuser_UOmYJok8Lpfl Posted at 5-15 23:45
You all are right that better flight planning would most likely prevent that case that actually happened a long time ago but that is not the point.
I will not drive my car with 2 litters of feul but I most definitely not want the car to stop at that point.
The point is that if the battery has about 4% left when indicating 0. It should not force landing at 8%

When your done to the last few % of the battery its very hard to know exactly whats left,  the same way the last 2 litres of fuel in your tank may get another few miles or might run out in seconds because you go down a steep slope and the fuel moves in the tank.  

For safety dont fly under 25% battery and then you'll always have some reserve if something unknown happens.

Also DJI doest force landing at 8% just push the left stick up to override that.
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djiuser_UOmYJok8Lpfl
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DAFlys Posted at 5-15 23:56
When your done to the last few % of the battery its very hard to know exactly whats left,  the same way the last 2 litres of fuel in your tank may get another few miles or might run out in seconds because you go down a steep slope and the fuel moves in the tank.  

For safety dont fly under 25% battery and then you'll always have some reserve if something unknown happens.

As I said. I know that it's possible to override the force landing but it is very difficult to do it precisely and that means you losing attitude or battery life by flying up.
But again. Battery percent is exact science. Flying time is what can fluctuate do to wind movement and temperature. Why not just display actual data?
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JJB*
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djiuser_UOmYJok8Lpfl Posted at 5-15 23:45
You all are right that better flight planning would most likely prevent that case that actually happened a long time ago but that is not the point.
I will not drive my car with 2 litters of feul but I most definitely not want the car to stop at that point.
The point is that if the battery has about 4% left when indicating 0. It should not force landing at 8%

asking is always allowed  ;-)

But DJI will not change this. Battery forced landing is a safety issue, it forced a remote pilot to land the craft, always better than try to make it home flying at 100 meters and at 0% falling out of the sky!

Critical low battery landing is afaik 10% for a Mini3Pro, it is a dynamic value though.
Flying far away from HP and at high heights it can trigger this type of landing at 10% or 40 %....
Tech problem is that the rate of battery% going down depends on many variables (temp, batt quality ect) , so imo it is very accurate within plus or minus variations.

Loosing height during critical battery...just pull up max and you will gain height. Only the max power output is reduced, so not the same flight performances with 25% battery etc.  So...land between 20 and 30% always.  ;-)

cheers
JJB
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Sean-bumble-bee
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"and I accidentally manually triggered rth at 65%."  if RTH couldn't  get the drone home starting at 65% it must have been somehead wind. Are you aware you can cancel an RTH?

Forced landing battery percentage varies with height, it is not fixed.
Critical battery landing is fixed and if you are not near or over the homepoint by then you are in severe difficulties.
I may be wrong but I rarely make flights where I have to start getting worried about battery percentages so I don't really pay that much attention to colours etc., but doesn't the Fly app indicate battery charge in figures and, via the colour of the 'circumference' surrounding those figures, how close the battery is to the amount of charge required to get the drone home safely?
Ok, we can't really plan for a long term reversal in wind direction, equally can we expect DJI to somehow know of that and, before hand, give corresponding indications? But once you could see that things were getting iffy why not look for an alternative landing site. There's a great video on youtube of someone who flies a recent released Mavic 3 MILES downwind over open sea, cancels the low battery RTH and flies further downwind. Then, when they finally start to bring the drone back they realised they were not going to make it and diverted the drone to a small island.
If feasible, did you reduce RTH height to get into slower moving air? (BUT you need to check whether that would cancel the RTH. DJI 'messed' with things a while back and added certain stick movememnts cancelling an on going RTH process but I do not think commanding a descent whilst actually flying towards home was one of the additions, it would, IMO, be daft if they did. )

For that matter I have seen at least one youtube of someone saving their drone by flying some distance with the drone in forced landing, they were over water so it was either fly or 'drown'.
Since many people will make the majority of their flights over land I think it is safer for DJI to have forced and critical landings that bring the drone down in a controlled manner rather than leaving it to pilots who would push the boundaries until the descent was in an uncontrolled manner or free fall.


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DAFlys
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djiuser_UOmYJok8Lpfl Posted at 5-16 00:09
As I said. I know that it's possible to override the force landing but it is very difficult to do it precisely and that means you losing attitude or battery life by flying up.
But again. Battery percent is exact science. Flying time is what can fluctuate do to wind movement and temperature. Why not just display actual data?

Battery percent is not an exact science.   You should  for safety be aiming to land in the 25% free range,  and if nothing else running the batteries to below that regularly will severely limit that batteries life
2023-5-16
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