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

[Landbo]

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.

I think this is the wrong way of thinking. Let us first determine what caused my Anafi to "fold her wings together" and drop out of the sky. You probably do not change the water in the cooler of your car because the right rear wheel is punctured !!!

Regards, Leif.

 

[MustangPhil]

Do any of you guys know where the Exterior Air Temparature sensor is located on the Anafi, or there is any ? (Something must trigger the message ‘cold exterior temp’ but where ?)
The battery itself could have one to prevent over-heating, but my guess, even in cold weather, is the battery is not ‘that cold’ after an intensive flight.
Does the Anafi calculate a delta between the Exterior Air Temperature and the battery Temperature to estimate a reasonable ‘Remaining Flight Time’ ?

 

[Dirk_ANAFI]

Do any of you guys know where the Exterior Air Temparature sensor is located on the Anafi, or there is any ? (Something must trigger the message ‘cold exterior temp’ but where ?)
The battery itself could have one to prevent over-heating, but my guess, even in cold weather, is the battery is not ‘that cold’ after an intensive flight.
Does the Anafi calculate a delta between the Exterior Air Temperature and the battery Temperature to estimate a reasonable ‘Remaining Flight Time’ ?

I didn't find any reports about an external temperature sensor on Anafi.
But it must have at least 2 temp sensors:
- in the battery
- on the mainboard
I think there is one on the mainboard, because the fan obviously reacts on the temp running at different speeds.

 

[Landbo]

Do any of you guys know where the Exterior Air Temparature sensor is located on the Anafi, or there is any ? (Something must trigger the message ‘cold exterior temp’ but where ?)
The battery itself could have one to prevent over-heating, but my guess, even in cold weather, is the battery is not ‘that cold’ after an intensive flight.

Does the Anafi calculate a delta between the Exterior Air Temperature and the battery Temperature to estimate a reasonable ‘Remaining Flight Time’ ?

I'm almost 100% sure there is a temperature sensor in the smart battery. I justify that you cannot charge the battery if it is too hot internally and you cannot fly if it is too cold. I do not think there is a temperature sensor in the body of Anafi.

I guess FW also takes the battery's internal temperature into consideration when calculating the percentage of power left.

Regards, Leif.

 

[Landbo]

I didn't find any reports about an external temperature sensor on Anafi.
But it must have at least 2 temp sensors:
- in the battery
- on the mainboard
I think there is one on the mainboard, because the fan obviously reacts on the temp running at different speeds.

Strange as my fan always runs at full power when I turn on the Anafi. My board is Rev xxxxxx 003.

Regards, Leif.

 

[Moonfly]

I put mi cent. If the air temperature is 2 degrees on the ground, for example 50 meters in height, it is much less. Can this affect this?

 

[MustangPhil]

Yes, I’m pretty sure there is a temperature sensor in the battery that prevents over-heating during flight.
The fan starts immediately even during cold temperature and there may be a correlation between fan speed and the battery temperature but I did not remark that.

I was just thinking :

- The battery, In usual Exterior Temperature as above 10°C, is always ‘too hot’. The main risk for the battery in normal operating is the over-heating.
- During flight, the motors do generate heat due to friction, the ESCs draw current and do heat (touch them on a racer, whatever the Exterior temp... they’ll burn your fingers, I have even burnt ESC on a little tiny whoop).
- The GPS sensor and the main board, as well as the barometric sensor, the magnetometer, and gyro or accelerometers may not be that much influenced by low temperatures. In the contrary, a low temperature is what is searched for main boards, and thermal expansion has a bad influence on MEMs sensors such as the accelerometer.

To me the risk of the low temperatures is mainly on the battery at startup (stayed long in a non-heated environment, the garage or car during winter...). To reduce this risk, the advice is to keep the battery in your coat before flight in winter’ and store the battery inside the house at night (which Lambo did)

The second risk for the battery is the low temperature affects the chemical process in the lithium / carbon exchanges of ions and reduce dramatically the efficiency of the battery at low Exterior temperature particularly when ‘almost empty’ (at that low Exterior temperature when the voltage goes low, I would not start the Anafi fan during RTH to avoid cooling more and draw unnecessary current from the fan that is useless in this situation).
The last risk is propeller ice depot and stall but is was not the case here (though propeller icing was reported by the guy who did a beautiful winter snow footage over Switzerland but it did not induce the Anafi stall).

The altitude has of course an effect on the temperature (you loose 2°C every 1000 ft/ 330m in the ‘standard atmosphere’). But at 50m the decrease in temp should be less than a degree and should not be an issue in the case. The wind speed at 50 m heigth can be doubled and participates in the cooling process I suppose.

That’s why I was wondering if there was an other temp sensor ‘far from the battery or the parts that heat during flights’

 

[Dirk_ANAFI]

Strange as my fan always runs at full power when I turn on the Anafi. My board is Rev xxxxxx 003.

Regards, Leif.

I think, there are at least 2 speed steps. But I may be wrong.
Once I put it on a pillow not realizing, that the fan opening was blocked for air flow. After a few seconds the fan became much louder then...

 

[Vassilag]

[QUOTE="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. [/QUOTE]

I agree with it, but the machine is unable to calculate with accuracy how much energy will be needed in every case. A sudden wind burst makes bigger difference than the temperature of the battery IMHO. Also please keep in mind that returning to home Anafi will fly at the minimum RTH altitude you have set. 30 meters by default.

In general automatic RTH should not be guaranteed. On the other hand I noticed that the entire flight lasted only 16 minutes which is less than usual. Either the machine faced strong winds ( the wind speed at 100 m is very different than surface) or the battery has lost capacity.

Regards, Vassilis

 

[ufosaboveus]

I think this is the wrong way of thinking. Let us first determine what caused my Anafi to "fold her wings together" and drop out of the sky. You probably do not change the water in the cooler of your car because the right rear wheel is punctured !!!

Regards, Leif.

Leif, I do understand where you are coming from but considering things like cold weather can influence battery life and we are not sure the programming accounts for it in its calculations... I don't honestly see how giving owners the option of setting a more conservative auto RTH option would be a bad thing. Leave the default where it is but simply allow users to change it in settings if they wish to. That way if flying in winter conditions or maybe for owners that just feel more confortable with a larger margin for error... we can change the auto RTH to 15% or even 20% if we want. I understand a manufacturer not wanting to allow users to make choices that make it more likely for a drone to crash... that makes good business sense. What I would propose would be more conservative however so there is honestly do down side to the manufacturer as long as they leave 10% the minimum setting you can select.

 

[Jagerbomb52]

Leif, I do understand where you are coming from but considering things like cold weather can influence battery life and we are not sure the programming accounts for it in its calculations... I don't honestly see how giving owners the option of setting a more conservative auto RTH option would be a bad thing. Leave the default where it is but simply allow users to change it in settings if they wish to. That way if flying in winter conditions or maybe for owners that just feel more confortable with a larger margin for error... we can change the auto RTH to 15% or even 20% if we want. I understand a manufacturer not wanting to allow users to make choices that make it more likely for a drone to crash... that makes good business sense. What I would propose would be more conservative however so there is honestly do down side to the manufacturer as long as they leave 10% the minimum setting you can select.

This option is actually a very good one and one that I have on my Autel X-Star App. It tells me battery temp, if the cells are balanced, just how good my battery is and I can adjust when RTH will kick in and when a critical battery warning happens.

A lot of good info on one page of the App.

 

[Landbo]

[QUOTE="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.

I agree with it, but the machine is unable to calculate with accuracy how much energy will be needed in every case. A sudden wind burst makes bigger difference than the temperature of the battery IMHO. Also please keep in mind that returning to home Anafi will fly at the minimum RTH altitude you have set. 30 meters by default.

In general automatic RTH should not be guaranteed. On the other hand I noticed that the entire flight lasted only 16 minutes which is less than usual. Either the machine faced strong winds ( the wind speed at 100 m is very different than surface) or the battery has lost capacity.

Regards, Vassilis[/QUOTE]

Sorry but it was one of those rare days where there was no wind here on the place. Anafi flew "only" 50 meters horizontally to get over the home point. According to the log, 73% of the battery's capacity has been used.

The battery could not charge more power even though it "only" showed a residual capacity of 92% when it was insert into Anafi. Hence the shorter flight time.

You can also look directly at the graph of the log that Anafi flew at 100 meters high to the home point and began the descent as she "folded the wings together" and fell to the ground.

Regards, Leif.

 

[Landbo]

I think, there are at least 2 speed steps. But I may be wrong.
Once I put it on a pillow not realizing, that the fan opening was blocked for air flow. After a few seconds the fan became much louder then...

I could never think of covering the fan under normal circumstances, but did a careful test to verify your statement. It actually sounds like the fan is getting a bit faster when the CPU / graphics processor gets hotter. However, there is only a minimal increase in the number of revolutions occurring on my fan.

Regards, Leif.

 

[Landbo]

Leif, I do understand where you are coming from but considering things like cold weather can influence battery life and we are not sure the programming accounts for it in its calculations... I don't honestly see how giving owners the option of setting a more conservative auto RTH option would be a bad thing. Leave the default where it is but simply allow users to change it in settings if they wish to. That way if flying in winter conditions or maybe for owners that just feel more confortable with a larger margin for error... we can change the auto RTH to 15% or even 20% if we want. I understand a manufacturer not wanting to allow users to make choices that make it more likely for a drone to crash... that makes good business sense. What I would propose would be more conservative however so there is honestly do down side to the manufacturer as long as they leave 10% the minimum setting you can select.

Then there must also be an error in Parrot's way of calculating the remaining power on the battery since I am very sure there is a temperature sensor built into there smart-battery.

Think it is not necessary to change the zero point if Parrot has control over their calculations but after what I and others have experienced, Parrot might have to look at their calc again.

However, I just want to wait and hear what Parrot says about what happened before a judgment can be made.

Regards, Leif.

 

[ROBANAFI]

Sorry, asked this previously but didn't get an answer. how old is your battery?

 

[ROBANAFI]

I think, there are at least 2 speed steps. But I may be wrong.
Once I put it on a pillow not realizing, that the fan opening was blocked for air flow. After a few seconds the fan became much louder then...

Probably not best to sleep with the Anafi

 

[AaronB]

Sorry, asked this previously but didn't get an answer. how old is your battery?

My thoughts also. LiPo batteries lose efficiency with aging. Depending on usage a typical LiPo battery can lose up to 50% (or more) of usable charge over time. I've had some LiPo's that are completely useless after two years. Others just keep on going, but deliver at a reduced power rate. Personally, if I was planning a flight close to full battery discharge, I would do a test flight first by hovering 3 feet of the ground until auto landing kicks in. Note the duration of the test flight, subtract 20% and use that as my RTH indicator. I just don't think software blindly monitoring voltage and/or power consumption will ever accurately predict the cut-off point of an aging LiPo battery.

 

[Landbo]

Sorry, asked this previously but didn't get an answer. how old is your battery?

Sorry but there is a lot to answer. The battery I used is the original one that came with Anafi. It also means that it is that battery I have, there has most charge/discharge laps. The battery is thus around 6 months old as my Anafi.

Regards, Leif.

 

[Landbo]

My thoughts also. LiPo batteries lose efficiency with aging. Depending on usage a typical LiPo battery can lose up to 50% (or more) of usable charge over time. I've had some LiPo's that are completely useless after two years. Others just keep on going, but deliver at a reduced power rate. Personally, if I was planning a flight close to full battery discharge, I would do a test flight first by hovering 3 feet of the ground until auto landing kicks in. Note the duration of the test flight, subtract 20% and use that as my RTH indicator. I just don't think software blindly monitoring voltage and/or power consumption will ever accurately predict the cut-off point of an aging LiPo battery.

I know everything about it to, Aaron. I have 2 ps. 4000MA S3 batteries I used for my first hexacopter. They are almost 9 years old now and still have over 80% capacity back last summer I measured on them. They are now being used in my 1.8 meter CUB. On the other hand, a set of 5000MA S3, bought a month later, is died and buried long ago because they could deliver no power more. Of course, my Li-Po has always been stored below 3.85 volts on each cell and has never been charged before they have cooled down after use.

But since you do not trust the built-in intelligence of your smart batteries, you must feel cheated in your wallet as you can then use a dumb Li-Po battery for US $ 10-15 each to power your Anafi and do a self watch for the fly-time. Among other things, it is a smart low-voltage RTH you pay 5-6-7 times overprice of a smart battery to handle for you.

Regards, Leif.

 

[Seitenwerk]

I guess we should all accept that that may have been a bad luck incident. Could have been caused by temperature or other reasons, could have also been a technical error. We don’t know. I don’t think with what has been said here so far that anyone did anything wrong. The thread owner is right in that we should be able to trust the device and battery with its calculation. Even if extrem cold weather is always a situation where beeing careful is never a bad idea.

But in the end I guess this was a special incident and as long as we are not starting to see hundreds of threads with the same problem of devices just shutting off we can continue trusting our birds.

It reminds me of all the problems I have seen on the DJI forums like fly aways, or badly designed battery connections which lead to batteries just jumping out of the drone in mid flight (DJI Spark).