Hi,

Today my P4P activated the critical low warning at 24% battery even though I have the warning set for 10%.  Once it had decided to land I had no way of switching it off or even worse, I could not hit the RTH button to bring my drone home. Being out over the ocean made this a bit scary and luckily I navigated home  safely by manually keeping the drOne in the air even though it wanted to land in the sea.

Is there a way to switch off the auto land once it is engaged, I understand that it is a safety feature,  but deciding to land over the ocean when there is 24% battery kinda sux especially as there was no way of hitting return to home.

Thanks

This means that you were probably flying in windy conditions and had put the battery into this mode.  You can stop the bird descending so you can bring it home.

RTH will not work when you are in critical battery status.  

The % indication is only a rough guide and if you fly with a partially discharged battery it can be quite misleading.
What's important to the Phantom is the actual voltage it can get from the battery.
To see what the battery was supplying on that flight...
Go to http://www.phantomhelp.com/LogViewer/Upload/
Follow the instructions to upload your flight record.

You should give more details. what you describe might well be a perfectly normal behaviour, under certain user settings and modes of flight...

Labroides Posted at 2017-7-5 00:44
The % indication is only a rough guide and if you fly with a partially discharged battery it can be quite misleading.
What's important to the Phantom is the actual voltage it can get from the battery.
To see what the battery was supplying on that flight...

Thanks,

I uploaded and took screen shots, it was around 19m24sec that critical warning kicked in. Could it have been the heavy current draw (pic 1 purple bit) that caused the critical battery warning to kick in?

As Labroides posted. you really need to upload to msinger's phantomhelp link above to get a clear picture.

Mark The Droner Posted at 2017-7-5 02:27
As Labroides posted. you really need to upload to msinger's phantomhelp link above to get a clear picture.

Why is it that whenever I suggest using Phantomhelp, that the majority of flyers go to Airdata?
Airdata is next to useless for investigating incidents as it just gives a brief summary.
What's important is the actual voltage at the time of interest.
Phantomhelp gives a complete readout of everything happening every 1/10th of a second during the flight.

Labroides Posted at 2017-7-5 02:37
Why is it that whenever I suggest using Phantomhelp, that the majority of flyers go to Airdata?
Airdata is next to useless for investigating incidents as it just gives a brief summary.
What's important is the actual voltage at the time of interest.

my web browser redirected me there

You need a new web browser.

Mark The Droner Posted at 2017-7-5 02:48
You need a new web browser.

yeah im a noob in this world lol

Labroides Posted at 2017-7-5 02:37
Why is it that whenever I suggest using Phantomhelp, that the majority of flyers go to Airdata?
Airdata is next to useless for investigating incidents as it just gives a brief summary.
What's important is the actual voltage at the time of interest.

ok, finally

this is the voltage

1,200 feet altitude is pretty high (and illegal)!

dancopter Posted at 2017-7-5 03:04
1,200 feet altitude is pretty high (and illegal)!

Please do not go around making false claims. Many forum users do not live in countries with height limits. I often fly at 1640 feet max height as it is legal to do so where I live. Where the original poster lives it is also legal outside of controlled airspace in Australia.

It's getting tiring with the trolling of people about what is or is not illegal from people who are clueless as to the laws where others fly their drones.

Mark The Droner Posted at 2017-7-5 02:27
As Labroides posted. you really need to upload to msinger's phantomhelp link above to get a clear picture.

Also read this post. I went to critical battery at 35% hovering in a strong wind.  However that wind also brought me home as a tailwind.

http://forum.dji.com/forum.php?mod=viewthread&tid=89101

What you need to do is provide us with a link after you have uploaded your data to phantomhelp.  So after uploading, you would copy the url and then paste it to this thread.  

I guess you didn't charge the battery to full on the day of the flight?  

The voltages should have been higher for 25%, could have been due to lack of recent charging, maybe from heavy use of the throttles, maybe due to strong wind, temperature etc.  
At that combination of voltage and height an auto landing seems reasonable.

Next time, charge it properly and bring it back over land by 30%.

Mark The Droner Posted at 2017-7-5 03:53
What you need to do is provide us with a link after you have uploaded your data to phantomhelp.  So after uploading, you would copy the url and then paste it to this thread.

Ok, here is link

http://www.phantomhelp.com/LogViewer/FLPWBFXIAXIMA4H8VU60/

Thanks

Nigel_ Posted at 2017-7-5 04:19
I guess you didn't charge the battery to full on the day of the flight?  

The voltages should have been higher for 25%, could have been due to lack of recent charging, maybe from heavy use of the throttles, maybe due to strong wind, temperature etc.  

Hi Nigel,

Thanks it had just been under heavy throttle which must have pushed the voltage down enough to trigger the critical warning.

looking at the log, the voltage increases again as drone was heading home (and load had reduced), though by this point critical warning was already engaged.

I am going to set my C2 button for battery info and make sure I monitor batteries before and during  flights.

Nigel_ Posted at 2017-7-5 04:19
I guess you didn't charge the battery to full on the day of the flight?  

The voltages should have been higher for 25%, could have been due to lack of recent charging, maybe from heavy use of the throttles, maybe due to strong wind, temperature etc.  

He had already flown 19 minutes. I doubt he did that on a battery that was not charged as he had 99% at start of flight.

Aerotheque Posted at 2017-7-5 04:52
Ok, here is link

http://www.phantomhelp.com/LogViewer/FLPWBFXIAXIMA4H8VU60/

18m 56.1s        P-GPS        17satellites        807.4ft        0ft        18.6mph        1,513.4ft        27%        14.568V        3.641V        3.648V        3.647V        3.632V        0.016V        The remaining battery is only enough for RTH. Return home now.


You were already being warned to bring the bird home. Ignoring this warning led to your critical low battery situation.

19m 21.4s

Auto Landing

16satellites

1,233.6ft

0ft

36.3mph

2,510.0ft

25%

14.39V

3.595V

3.606V

3.605V

3.584V

0.022V

Critically Low Power. Aircraft Landing

Aerotheque Posted at 2017-7-5 04:52
Ok, here is link

http://www.phantomhelp.com/LogViewer/FLPWBFXIAXIMA4H8VU60/

Not sure why you are complaining, from the height you were flying it took over 2.5 minutes to land by which time it only had 14% battery left, and that was landing with almost zero wind and with a bit of power saved by you flying it back to land.  If it had waited until the 10% you had set before starting to land then it would have had -0.5% left ... it would have fallen the last 25 foot.

blackcrusader Posted at 2017-7-5 05:17
18m 56.1s        P-GPS        17satellites        807.4ft        0ft        18.6mph        1,513.4ft        27%        14.568V        3.641V        3.648V        3.647V        3.632V        0.016V        The remaining battery is only enough for RTH. Return home now.

yes, I was 450 meters away with 27% battery when RTH kicked in, so i ignored it.

Just trying to establish what caused it the critical battery at 24% as i have never had this happen before.

Basically at 18 mins you are given an RTH warning as the software wants to bring you home before you get into a situation like the one you have.   I often plan flights so that I start the home return at max height from long distances to give the bird enough time to return. I also fly into headwinds so that I have a tail wind on the return and can often scoot home with fast speeds on full throttle.

I prefer to have landed or be around my home point by the time I have 20% battery remaining.  

blackcrusader Posted at 2017-7-5 05:28
Basically at 18 mins you are given an RTH warning as the software wants to bring you home before you get into a situation like the one you have.   I often plan flights so that I start the home return at max height from long distances to give the bird enough time to return. I also fly into headwinds so that I have a tail wind on the return and can often scoot home with fast speeds on full throttle.

I prefer to have landed or be around my home point by the time I have 20% battery remaining.

Yes, few lessons for me in this one.

Cheers

Nigel_ Posted at 2017-7-5 05:27
Not sure why you are complaining, from the height you were flying it took over 2.5 minutes to land by which time it only had 14% battery left, and that was landing with almost zero wind and with a bit of power saved by you flying it back to land.  If it had waited until the 10% you had set before starting to land then it would have had -0.5% left ... it would have fallen the last 25 foot.

Hi nigel,

I was more concerned with not being able to engage RTH once the critical warning activated,  as well as what caused the critical warning  to kick in so early. This is the first time I have had a critical warning (i would never let it drop to 10%)  and it caught me off guard.

It's not a complaint but more of a concern.

Thankfully the drone did not end up swimming with the dolphins, so I am happy.

Anyway, thanks everyone.. this noob (me) is a little wiser.

Really appreciate all the help

























So, no complaints here

Aerotheque Posted at 2017-7-5 06:33
Hi nigel,

I was more concerned with not being able to engage RTH once the critical warning activated,  as well as what caused the critical warning  to kick in so early. This is the first time I have had a critical warning (i would never let it drop to 10%)  and it caught me off guard.

Yes, I couldn't think of a better word than "complaint".

I think the answer was a combination of the height and the voltage drop due to using full throttle.  The aircraft was just being cautious and making sure it could get down by 10% even if there was a strong gust of wind or an updraft.

RTH starts with flying up to the RTH altitude and using extra power to do so, the opposite of what is required if the battery voltage goes critical.  Not surprising it doesn't allow it, although in some circumstances you can end up landing with a lot of battery left, especially if you are in sports mode.

10% is effectively an empty battery, below that is for emergency use only, it has to restrict motor power and will start to struggle against wind, you didn't have a lot left.

Aerotheque Posted at 2017-7-5 05:39
Yes, few lessons for me in this one.

Cheers

Yes lessons we all learn. On my flight I was hovering in a strong wind taking a sunrise video. Did not expect to see critical battery when I had 35% battery left. Also it's know you cannot use RTH when in Critical Low battery auto landing mode. What you can do is maintain height and fly the bird home.

I too was at max height 500m 1640 feet and some distance away from home point.  I was fortunate that I had the wind behind me so flew home at over 50mph as I was descending and I had also returned to good voltage in the Green and had 26% battery left at home point.
Just watch the videos and look at the clouds ripping past above me.