My Anafi has now also fall out of the sky. :-(

[Landbo]

Tested after I had photographed the sunrise the automatic RTH function. With my quad hovering 50 meters from the starting point at a height of 100 meters, I waited until the automatic RTH function came into operation, which happened at 10% battery. Anafi flew to the home point and began to reduce altitude for landing. With 7% battery back all the motors suddenly stopped and Anafi was dropped the last about 30 meters so its fell on the back in some tall grass 3 meters from where I stood. Visible damage is 5 props blades but otherwise apparently nothing more as everything works. Has raised an case at Parrot to get settled why the engines stopped 30 meters above the ground. I have to think about it can happen again and then it is not certain that Anafi lands in high grass this time !!!



Regards, Leif.

 

[Seitenwerk]

Was it cold outside? Very low temperatures will lead to battery capacity/power reduction. So it is possible that even a battery showing 20% may suddenly shut down.

 

[Seitenwerk]

I wouldn’t generally say that 10% are only seconds. But it really depends on weather conditions or to be precise battery temperature and condition. I „could“ be absolutely fine and still word for a few minutes or at least to get back safely. But it „could“ also shut off in a few seconds. The older the battery gets the more likely it may be that it’s condition is not as good any more and that you can’t trust 10%

 

[Jagerbomb52]

In Landbo defense he was testing the automatic RTH function which did not kick in till 10% battery. The firmware should have just landed the Anafi where it was knowing there was not enough power left to fly back to the home location and not just shut off. This is built into many different UAV's

 

[Seitenwerk]

I think that in the manual it is said that the automatic RTH is dynamic and not set to a fixed percentage. The manual states that the drone always checks the distance and the required power to geht back to knit RTH.

 

[Dirk_ANAFI]

I think that in the manual it is said that the automatic RTH is dynamic and not set to a fixed percentage. The manual states that the drone always checks the distance and the required power to geht back to knit RTH.

Yes, I hope they also calculated with different battery temperatures ...!?

 

[Seitenwerk]

Just a wild guess, but I don’t think they or any other drone/device do. I don’t think that you can calculate that anyway, as battery level is basically a bit of guessing anyway. At least they give you a warning in case of low temperature

 

[IM35461]

Was it beeping and jerking it's props when you got to it (like my one was)?

 

[Landbo]

Was it cold outside? Very low temperatures will lead to battery capacity/power reduction. So it is possible that even a battery showing 20% may suddenly shut down.

Cold and cold, the air temperature was +5 degrees celsius and the battery has been stored for +20 degrees at night so it should not be the cold that can be the cause of the crash.

Hopefully, Parrot calculates the percentage of power on the battery from the voltage, like any other manufacturer, and not the flight time !!!

I'm looking forward to hearing what Parrot says.

Regards, Leif.

 

[ROBANAFI]

Sorry to hear about this but welcome to the "not user error club" Hopefully thats what Parrot will tell you! How old was the battery? i know the warranty on them is only 6 months so i wonder if they need replacing every so often?

 

[Landbo]

When your battery reaches 10% you only have seconds to land. Generally not enough time for a RTH. You shouldn't use RTH with less than 30% battery power, and certainly shouldn't be flying with only 10% left.

Look at it this way. When an RC car's battery runs low, it slows to a halt harmlessly. When a quad's battery runs low it "falls from the sky." and crashes. Flying with a battery at 10% is taking a serious risk - especially in cold weather.

Sorry about your crash - I'm glad it only damaged a few props., but I have to chalk this one up to operator error.

The time when the automatic RTH kicks in is not something I decide when to happen, but is something that Parrot has written into their own firmware. In contrast to many other manufacturers, Parrot uses the low percentage of battery for residual power when it is time to return home when Anafi is so near home.

Besides, my Anafi vas hovering for at least 3 minutes and waited for the battery voltage to be so low that it was time to automatically return home.

Pilot error no I do not think so, it must instead be a Parrot error when Anafi does not automatically go home before the battery voltage becomes too low. Otherwise, it makes no sense to make an automatic RTH function for low battery voltage.


Regards, Leif.

 

[Seitenwerk]

DJI drones do exactly the same thing Parrot does: calculate the power needed for return based on current position and init an RTH (after a warning you can cancel) when close to calculated limit. The problem is that current voltage still doesn’t tell you what the current battery level is. It is more or less guessing based on those values. Usually that’s fine but under certain circumstances, like old batteries or very cold weather a sudden loss of provided voltage/power can happen, especially when it’s already at a low percentage.

 

[Landbo]

In Landbo defense he was testing the automatic RTH function which did not kick in till 10% battery. The firmware should have just landed the Anafi where it was knowing there was not enough power left to fly back to the home location and not just shut off. This is built into many different UAV's

Completely true.

I think that in the manual it is said that the automatic RTH is dynamic and not set to a fixed percentage. The manual states that the drone always checks the distance and the required power to geht back to knit RTH.

Yes exactly how RTH should work on Anafi.

Yes, I hope they also calculated with different battery temperatures ...!?

I expect that parrot has the battery temperature in their calculations because otherwise there are many Anafi's that will fall out of the air right now.

Just a wild guess, but I don’t think they or any other drone/device do. I don’t think that you can calculate that anyway, as battery level is basically a bit of guessing anyway. At least they give you a warning in case of low temperature

No low temperature warning.

It is not guess in calculating the residual battery power when using a smart battery. It is actually a reasonably simple calculation. But there may be a mistake in Parrot's equation.

Regards, Leif.

 

[Landbo]

Was it beeping and jerking it's props when you got to it (like my one was)?

No Miss Anafi was stone-dead and the battery turned off when she came down. When I picked her up from the ground and turned on the battery, Anafi started up normally as nothing had happened.

Regards, Leif.

 

[Seitenwerk]

Sounds like the typical problem i was talking about. The same reason why people sometimes notice their phone suddenly switching of when still at 20-30% because the battery couldnt provide enough power as required at that moment . Afterwards you can switch it on again like nothing happened.

 

[Landbo]

Sounds like the typical problem i was talking about. The same reason why people sometimes notice their phone suddenly switching of when still at 20-30% because the battery couldnt provide enough power as required at that moment . Afterwards you can switch it on again like nothing happened.

If so, there is an error in the way you calculate the residual effect. You should never go so close at the battery shut off point.

Regards, Leif.

 

[Kilrah]

Probably a difference in what "low battery RTH" means for the different manufacturers. Looks like for Parrot it's a "last chance effort" aka you should never go even close or rely on it, it'll jsut try to save you if you completely forgot about battery.

On DJI... well it's configurable but by default it is on the very safe side, and has multiple levels of "urgency".
The battery metering is also much more sophisticated on DJI stuff from what it looks.

 

[Seitenwerk]

I don’t think that there is much difference in behavior between parrot and DJI. This was just a case of bad luck/faulty device or battery or otherwise we would hear of much more incidents like these. DJIs App shows the estimates remaining flight time which is calculated on current usage and remaining percentage but otherwise than that, behavior ist pretty much the same

 

[Landbo]

Probably a difference in what "low battery RTH" means for the different manufacturers. Looks like for Parrot it's a "last chance effort" aka you should never go even close or rely on it, it'll jsut try to save you if you completely forgot about battery.

On DJI... well it's configurable but by default it is on the very safe side, and has multiple levels of "urgency".
The battery metering is also much more sophisticated on DJI stuff from what it looks.

That depends on what you calculate the percentage from. But has always been aware that Parrot and DJI do not use the same start/end point.

That DJI is trying to calculate the remaining flight time in minutes is completely wrong when that time suddenly can change with 5 minutes down even though the vessel has never come further than 1.5 meters just above the takeoff point.

I consider DJI's way of presenting technical things to be for nerd-sprouts who want a lot of sliders to pull in and a lot of indifferent things to look at.

Regards, Leif.

 

[ufosaboveus]

seems to me parrot should add a way to adjust the auto rth percentage. I would not think it would be that tough to up it to 15% maybe just as an added buffer. THe user can always override it if they want to.