Time/% before forced landing ?

[Topo]

I have had this happen a couple times now, where I am under 10% battery charge remaining, and as I’m bringing it back to land, it enters into a forced landing automatically. At what point does it decide to take over and land where ever it is? I’d like to avoid this the next time since it landed into the sandy beach before I could get to it. And the time before that, caused a bit of a tumble as well. It would help if I knew the exact percentage of battery charge remaining when it will force land. Then I could be sure to bring it down before then.

 

[old man mavic]

really why are you flying it down to such low levels ,you can set the level to give you a warning in the app
you are not doing your batteries any good taking them down so low all the time

 

[Unknown Pilot]

I've set my alarm for 30% but in reality I'm usually heading home somewhere between 50 and 60% if I'm flying at a distance. Batteries are expensive

 

[sar104]

The autolanding battery level is computed as the parameter SMART_BATTERY_landBattery, based on the height of the aircraft. It is entirely unrelated to any of the levels set in the app.

 

[Topo]

The autolanding battery level is computed as the parameter SMART_BATTERY_landBattery, based on the height of the aircraft. It is entirely unrelated to any of the levels set in the app.

Thanks...suffice to say I should probably land before 10%. There have been times when I’m very close to home, but want to capture one more, near, shot. These occasions seem risky, as the last time was just off the water at the beach. I’ve seen a couple YouTube vids of range tests, and that certainly looks most dangerous. They are usually getting close to home with less than 10% remaining, but I have not seen any lose the bird to an auto landing....yet.

 

[Starz]

That “one more,near,shot” worth 400.00?
Could be an expensive photo.

 

[slup]

I have had this happen a couple times now, where I am under 10% battery charge remaining, and as I’m bringing it back to land, it enters into a forced landing automatically. At what point does it decide to take over and land where ever it is? I’d like to avoid this the next time since it landed into the sandy beach before I could get to it. And the time before that, caused a bit of a tumble as well. It would help if I knew the exact percentage of battery charge remaining when it will force land. Then I could be sure to bring it down before then.

I see that you haven't yet got a full explanation to your question ...

The MA has the "critically low battery" threshold set to 10% ... (as all DJI drones I think?), which you can't change. That means it will force land immediately & that you can't cancel that. You can delay the landing though ... by constantly applying full throttle up in order to find a suitable place to land.

Repeatedly going down to 10% & below isn't wise ... both considering the battery life & the safety for the flight.

 

[sar104]

I see that you haven't yet got a full explanation to your question ...

The MA has the "critically low battery" threshold set to 10% ... (as all DJI drones I think?), which you can't change. That means it will force land immediately & that you can't cancel that. You can delay the landing though ... by constantly applying full throttle up in order to find a suitable place to land.

Repeatedly going down to 10% & below isn't wise ... both considering the battery life & the safety for the flight.

That's not quite correct. Both the low battery and critically low battery levels can be set in the app smart battery preferences, and have nothing to do with either RTH or autolanding. The battery level at which autolanding starts is computed in real time, based on aircraft height, as I mentioned in post #4.

 

[slup]

That's not quite correct. Both the low battery and critically low battery levels can be set in the app smart battery preferences, and have nothing to do with either RTH or autolanding. The battery level at which autolanding starts is computed in real time, based on aircraft height, as I mentioned in post #4.

I'm afraid that don't apply to the Mavic Air ... can be mistaken but that setting have never been visible in the battery preferences. Suspect that this setting is taken away from the Air through some mysterious DJI logic. Have carefully tested this "threshold" on a soccer field to conclude if height or distance affect the force landing but it lands at 10% if I'm on 1 meter or 50 meter altitude ... or 1 meter or 100 meter distance (didn't dare to test on larger distances )

 

[sar104]

I'm afraid that don't apply to the Mavic Air ... can be mistaken but that setting have never been visible in the battery preferences. Suspect that this setting is taken away from the Air through some mysterious DJI logic. Have carefully tested this "threshold" on a soccer field to conclude if height or distance affect the force landing but it lands at 10% if I'm on 1 meter or 50 meter altitude ... or 1 meter or 100 meter distance (didn't dare to test on larger distances )

View attachment 92119

Ah - so that is fixed or non-existent with the MA. It still has no relationship to the autoland level - that happens at the SMART_BATTERY_landBattery parameter that you can see in the txt logs, and you will notice that it is linearly dependent on OSD_height. It starts at around 11% and goes up from there. It doesn't depend on distance - that's used to compute SMART_BATTERY_goHomeBattery which determines the RTH point.

There's a discussion of how these values are altered by firmware parameters in this thread.

 

[slup]

Ah - so that is fixed or non-existent with the MA. It still has no relationship to the autoland level - that happens at the SMART_BATTERY_landBattery parameter that you can see in the txt logs, and you will notice that it is linearly dependent on OSD_height. It starts at around 11% and goes up from there. It doesn't depend on distance - that's used to compute SMART_BATTERY_goHomeBattery which determines the RTH point.

There's a discussion of how these values are altered by firmware parameters in this thread.

Yeah ... pretty logic to tie the auto land to height, the higher the sooner percentage wise it starts in order to reach ground before fumes is gone

Can add ... hrm an insight from an example from my earliest uneducated days.

Auto land battery percentage can't be lower then 10% (for the Air) & then add 1 % for approx each 30 meter height change ...

 

[sar104]

Yeah ... pretty logic to tie the auto land to height, the higher the sooner percentage wise it starts in order to reach ground before fumes is gone

Can add ... hrm an insight from an example from my earliest uneducated days.

Auto land battery percentage can't be lower then 10% (for the Air) & then add 1 % for approx each 30 meter height change ...

View attachment 92127

Yes - that looks about right.

 

[TerryOregon]

Let's see, where's that video where someone wanted to see what happens when you get to 0% battery (and you're still up). Here it is . . .

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[Scoobychief]

Let's see, where's that video where someone wanted to see what happens when you get to 0% battery (and you're still up). Here it is . . .

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Interesting indeed.

 

[GadgetGuy]

I have had this happen a couple times now, where I am under 10% battery charge remaining, and as I’m bringing it back to land, it enters into a forced landing automatically. At what point does it decide to take over and land where ever it is? I’d like to avoid this the next time since it landed into the sandy beach before I could get to it. And the time before that, caused a bit of a tumble as well. It would help if I knew the exact percentage of battery charge remaining when it will force land. Then I could be sure to bring it down before then.

I'll add one more log to the fire.
Whenever Autoland begins, typically at 10% unless set earlier, it starts descending, but the descent can still be overcome with full left stick, and you still have full lateral control. This means you also still have limited ability to ascend, and can continue flying back to the home point on a glide path. This condition continues well past 0%, up to 2 minutes after. However, and this is the answer to your question, once any battery cell drops below 3.0V, you can no longer stop the descent, and it starts descending in a controlled descent, but it will still keep flying forward with right stick, if you so choose, until it either runs into the ground, or the battery can no longer sustain flight. This is all true of the Mavic 2. It should also be true on the Mavic Air and Mavic Mini, but I don't own either to test it with. I have personally tested it with the Mavic 2, not intentionally!

 

[sar104]

I'll add one more log to the fire.
Whenever Autoland begins, typically at 10% unless set earlier, it starts descending, but the descent can still be overcome with full left stick, and you still have full lateral control. This means you also still have limited ability to ascend, and can continue flying back to the home point on a glide path. This condition continues well past 0%, up to 2 minutes after. However, and this is the answer to your question, once any battery cell drops below 3.0V, you can no longer stop the descent, and it starts descending in a controlled descent, but it will still keep flying forward with right stick, if you so choose, until it either runs into the ground, or the battery can no longer sustain flight. This is all true of the Mavic 2. It should also be true on the Mavic Air and Mavic Mini, but I don't own either to test it with. I have personally tested it with the Mavic 2, not intentionally!

Just to clarify again - you cannot set the autoland level - it is calculated by the FC based on the current height of the aircraft.

 

[Deleted member 109934]

I have had this happen a couple times now, where I am under 10% battery charge remaining, and as I’m bringing it back to land, it enters into a forced landing automatically. At what point does it decide to take over and land where ever it is? I’d like to avoid this the next time since it landed into the sandy beach before I could get to it. And the time before that, caused a bit of a tumble as well. It would help if I knew the exact percentage of battery charge remaining when it will force land. Then I could be sure to bring it down before then.

I just did another long-range over the lake test 5000m and came back with 3% power left, at 9% it slows down, at 3% it just lands, you can hold sticks up and control it a bit, but it will slowly land, if you are 5m over ground it will and, if you are 100m you will still fly until it goes down. Will post my video at one point

 

[Captain....Kirk]

Let's see, where's that video where someone wanted to see what happens when you get to 0% battery (and you're still up). Here it is . . .

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Thanks large for your video.

Let's see, where's that video where someone wanted to see what happens when you get to 0% battery (and you're still up). Here it is . . .

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For more detailed information, see our cookies page.

Accept third party cookies

Let's see, where's that video where someone wanted to see what happens when you get to 0% battery (and you're still up). Here it is . . .

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For more detailed information, see our cookies page.

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Thank you for sharing the video. Helped me a great deal.Tks large.

 

[GadgetGuy]

Just to clarify again - you cannot set the autoland level - it is calculated by the FC based on the current height of the aircraft.

Correct. Good point. I should have said set the Critical Battery Level, which then becomes the default Autoland, unless the current elevation requires an earlier Autoland, to account for the extra time needed for the descent. I rarely encounter the latter, since I usually fly from a hilltop over lower ground, but now I know why it sometimes happens before the Critical Battery level setting is reached.

 

[sar104]

Correct. Good point. I should have said set the Critical Battery Level, which then becomes the default Autoland, unless the current elevation requires an earlier Autoland, to account for the extra time needed for the descent. I rarely encounter the latter, since I usually fly from a hilltop over lower ground, but now I know why it sometimes happens before the Critical Battery level setting is reached.

The critical battery level is not a default autoland. It's purely informational.