why does flying on an less than 100% charged battery cause problems

[captain kush]

Howdy, This weekend I was flying my drone above my yard trying to catch a great sunset shot,which i got by the way. A minute or two after take off someone walked up and asked if they could launch a kayak from my beach in order to retrieve his crabpots,it seems his boat had problems after he had dropped his gear.Being a nice guy I landed my drone and went and showed where he could park and put his kayak in. I then returned to my drone that was sitting on the landing pad waiting, I launched and flew up to 200 ft and continued to take few photos of the sunset.As i was descending straight down and watching the bird overhead it suddenly started veering off sideways, I was able to control and bring it back , I then flew up about 20 ft to let it hover and it wanted to drift. Best I can come up with is that I took off on less than a full battery. I am wondering why these craft do this.Anyone know.
captain kush

 

[PaulSouthport]

The battery is not the cause of the erratic flight.

To answer the initial question - the remaining charge of a battery is an estimate based on its voltage under load. Being an estimate, it needs certain parameters to be accurate, such as a known starting point. Once it's partially discharged then the starting point is also an estimate.

The veering is more likely to be caused by strong gusts/compass error leading to atti mode/loss of sats/magnetic interference from something/wobbly fingers.
Check the flight log at DJI Flight Log Viewer for a real answer.

 

[captain kush]

Well, thanks for the reply but it does not help my question. I have read repeatedly not to fly on a non fully charged battery. There was zero wind and i had 17 sattelites. and it never changed to atti or anything other than the normal flight mode. When I landed I flew up overhead and it did the same type of drift. What does the starting point of the battery being an estimate have to do with erratic flight characteristics, that is the question. The drone was landed and then launched again without powering down. That should eliminate the BS about the starting point being an estimate.Oh and my fingers certainly were not wobbly. Looks like flight on a non 100% charged battery causes some malfunction that DJI cant figure out.
captain kush

 

[With The Birds]

Upload your flight log to phantomhelp log viewer, you will probably find that the AC switched to ATTI mode, this is standard operation where the flight controller senses an issue with the compass readings.

 

[PaulSouthport]

I did answer your question. The battery has no bearing on the erratic flight.
You can say 2 plus 2 = 5 as much as you like, it doesn't make it so.

 

[Meta4]

I have read repeatedly not to fly on a non fully charged battery. There was zero wind and i had 17 satellites. and it never changed to atti or anything other than the normal flight mode. When I landed I flew up overhead and it did the same type of drift. What does the starting point of the battery being an estimate have to do with erratic flight characteristics, that is the question.

The answer to that question is ... Nothing.
Starting with a partially discharged battery will cause the % battery indicator to give a false reading and can be the cause of fall-from-the-sky incidents or unexpected low battery autolanding because of low voltage.
It can't cause drifting.

The drone was landed and then launched again without powering down. That should eliminate the BS about the starting point being an estimate.Oh and my fingers certainly were not wobbly. Looks like flight on a non 100% charged battery causes some malfunction that DJI cant figure out.

Landing and taking off again is very different from launching with a battery that has been sitting for a week or two and slowly discharging.
Your battery % indicator should have been accurate.
The BS is joining the dots to imagine erratic flight is somehow linked to the battery.
To get to the bottom of the mystery, you need to look at flight data to see what was actually happening rather than what you guess might have happened.

To see a genuine case of launching with a partially discharged battery and why you shouldn't do it, read this thread: Water Loss

 

[Norry.]

Well, thanks for the reply but it does not help my question. I have read repeatedly not to fly on a non fully charged battery. There was zero wind and i had 17 sattelites. and it never changed to atti or anything other than the normal flight mode. When I landed I flew up overhead and it did the same type of drift. What does the starting point of the battery being an estimate have to do with erratic flight characteristics, that is the question. The drone was landed and then launched again without powering down. That should eliminate the BS about the starting point being an estimate.Oh and my fingers certainly were not wobbly. Looks like flight on a non 100% charged battery causes some malfunction that DJI cant figure out.
captain kush

Why such an aggressive attitude towards people putting time aside to try and help you?

 

[RémyHeli]

Flight Log does help and way to go. In absence of more evidence I would say craft did send warnings as was landed between and waited for some time, then at 2nd take-off checking again and battery readings not 100%. Maybe no message if quick landing and take-off, which could be easily tested.

Saying abnormal flight behavior dues to non full battery charge doesn't make sense at all so viewing flight log could clarify.

 

[Fruxen]

I have read repeatedly not to fly on a non fully charged battery.
captain kush

I'm not saying there is no truth to it, but the danger is exagerated on this forum IMO. Take it with a grain of salt.

I fully understand the concept of the % reading being only a guesstimate, but the battery is actively and continuously monitored by its own internal electronics. After many years of producing these batteries, why would a partially discharged battery suddenly go into this crazy physical state completely unknown and unexpected to the battery engineers at DJI? A ticking bomb just waiting to shut down at 50% or possibly blow up the neighbourhood, even though the voltage levels and other parameters are perfectly monitored at all times? I don't fully buy that story.

Sudden drone failures are quickly claimed to be because of partially discharged batteries, when in reality people have no idea of what actually happened in that particular incident. I say "Well you flew during a full moon, that's dangerous, the drone got unstable so that's the proof right there."

 

[Meta4]

I'm not saying there is no truth to it, but the danger is exagerated on this forum IMO. Take it with a grain of salt.

DJI advise you to only fly with a fully charged battery and the reason for this recommendation is a very good one.
We see way too many fall-from-the-sky cases that are due people launching with partially discharged batteries.
If you launch with a battery that has been sitting around for a week, slowly discharging, you are asking for trouble.
To see exactly what this is about look at the case mentioned in post #6 above.
The risk is not exaggerated at all.

 

[macoman]

I have taken off on 92% and even 88% battery charge and never have issues... I always land when battery reach around 45%.

 

[With The Birds]

I'm not saying there is no truth to it, but the danger is exagerated on this forum IMO. Take it with a grain of salt.

I fully understand the concept of the % reading being only a guesstimate, but the battery is actively and continuously monitored by its own internal electronics. After many years of producing these batteries, why would a partially discharged battery suddenly go into this crazy physical state completely unknown and unexpected to the battery engineers at DJI? A ticking bomb just waiting to shut down at 50% or possibly blow up the neighbourhood, even though the voltage levels and other parameters are perfectly monitored at all times? I don't fully buy that story.

Sudden drone failures are quickly claimed to be because of partially discharged batteries, when in reality people have no idea of what actually happened in that particular incident. I say "Well you flew during a full moon, that's dangerous, the drone got unstable so that's the proof right there."

There are too many incidents reported here and elsewhere depicting battery issues (particularity commencing flight with less than a freshly charged pack) for your suggestion of exaggeration to carry much weight.

I often fly with a pack at 60% or more without fear or issue. It is always within hours of the last time flown though.

Most issues seem to be with a pack that has been allowed to enter auto discharge. Consider you are the battery supplier to DJI and you are adding an auto discharge feature. The smart board already incorporates bleed resistors to provide for cell balancing during charging. The most cost effective way to implement auto discharge is to employ the bleed resistors. The resistors aren’t closely matched, they don’t need to be to provide for balanced charging. The imbalance will provide that during auto discharge the cells become out of balance and as a result you stand a good chance of one reaching critical low voltage early and without warning during flight. The outcome is obvious, shut down in flight without warning.

 

[Fruxen]

DJI advise you to only fly with a fully charged battery and the reason for this recommendation is a very good one.
We see way too many fall-from-the-sky cases that are due people launching with partially discharged batteries.
If you launch with a battery that has been sitting around for a week, slowly discharging, you are asking for trouble.
To see exactly what this is about look at the case mentioned in post #6 above.
The risk is not exaggerated at all.

In the thread you are referring to, the first warning was actually "Motor overloaded". Parts might be damaged before the AC even took off, causing voltage fluctuation and failure. We don't know, you just assume everything was perfectly healthy. Of all the many components that can fail inside the AC, it can only possibly be the battery, charged in a certain way? Not trying to be rude here but this kind of proves my point.

 

[Meta4]

In the thread you are referring to, the first warning was actually "Motor overloaded". It might be damaged before the AC even took off, causing failure. But of all the many components that can fail inside the AC, it can only possibly be the battery, charged in a certain way? Not trying to be rude here but this kind of proves my point.

Look at the cell voltages.
What more proof can there be?

 

[Morningdewd]

one X factor El Capitan .....a biggie ...did you smoke some KUSH before flying ????don't stone n drone bro

 

[Cruck]

Howdy, This weekend I was flying my drone above my yard trying to catch a great sunset shot,which i got by the way. A minute or two after take off someone walked up and asked if they could launch a kayak from my beach in order to retrieve his crabpots,it seems his boat had problems after he had dropped his gear.Being a nice guy I landed my drone and went and showed where he could park and put his kayak in. I then returned to my drone that was sitting on the landing pad waiting, I launched and flew up to 200 ft and continued to take few photos of the sunset.As i was descending straight down and watching the bird overhead it suddenly started veering off sideways, I was able to control and bring it back , I then flew up about 20 ft to let it hover and it wanted to drift. Best I can come up with is that I took off on less than a full battery. I am wondering why these craft do this.Anyone know.
captain kush

You sure it didn't get switched to atti mode in error.

 

[Firedrone]

Howdy, This weekend I was flying my drone above my yard trying to catch a great sunset shot,which i got by the way. A minute or two after take off someone walked up and asked if they could launch a kayak from my beach in order to retrieve his crabpots,it seems his boat had problems after he had dropped his gear.Being a nice guy I landed my drone and went and showed where he could park and put his kayak in. I then returned to my drone that was sitting on the landing pad waiting, I launched and flew up to 200 ft and continued to take few photos of the sunset.As i was descending straight down and watching the bird overhead it suddenly started veering off sideways, I was able to control and bring it back , I then flew up about 20 ft to let it hover and it wanted to drift. Best I can come up with is that I took off on less than a full battery. I am wondering why these craft do this.Anyone know.
captain kush

I cringe when I hear those words: straight down, and no wind. I believe it is not the battery at all but somthing called vortex spinn. I believe this is when your dronne makes a vacuum underneath it self and then falls into the vacuum. I have had a crash from 120m because of this, and because I did not know how to get out of it. I siplily tried to go straight back up, which will make the drone create a lager vacuum so fall faster. What you need to do to get out of a vortex spinn is go forward ( back and sideways may work but I believe that forward is the best) to get out of the vacuum. Carm days are the best days to get in a vortex spinn as there is no sideways air movement beneath the drone. A couple of tell tale signs are if you hear the moters going excessively fast and sound choppy. Also if the drone goes up or down without you telling it to.
So what I tend to do is come down in big spirals, always moving.

Hope it helps,

 

[davidzimagery]

I've flown twice with batteries that had been sitting and were partially discharged automatically. Both times, after a few minutes of fight, I got a verbal "Low battery, landing" warning. Luckily, the first time I managed to maneuver it from over a soybean field to a grass area. The second time was on purpose over my yard to confirm what would happen. I haven't had it happen when flying with a battery discharged by a recent flight. Recent being within a few hours.

 

[Meta4]

I cringe when I hear those words: straight down, and no wind. I believe it is not the battery at all but somthing called vortex spinn. I believe this is when your dronne makes a vacuum underneath it self and then falls into the vacuum. I have had a crash from 120m because of this, and because I did not know how to get out of it. I siplily tried to go straight back up, which will make the drone create a lager vacuum so fall faster. What you need to do to get out of a vortex spinn is go forward ( back and sideways may work but I believe that forward is the best) to get out of the vacuum. Carm days are the best days to get in a vortex spinn as there is no sideways air movement beneath the drone. A couple of tell tale signs are if you hear the moters going excessively fast and sound choppy. Also if the drone goes up or down without you telling it to.
So what I tend to do is come down in big spirals, always moving.

VRS or Vortex Ring State was an issue for the original Phantoms and the P2 series.
DJI slowed the descent rate twice to reduce it.
With the P3 and P4 series VRS was eliminated by angling the motors which were vertical on earlier models.
It is completely safe to descend vertically in still air with a P3 or P4 Phantom.

 

[tcope]

I'm not saying there is no truth to it, but the danger is exagerated on this forum IMO. Take it with a grain of salt.

I'd not say that anyone is exaggerating (though, in many cases it won't result in any issues), I'd say that the recommendation is usually aimed at a person who had limited experience in knowing where the limits and issues come from. So it's safer to simply recommend that it not be done. Most likely why DJI makes the same recommendation. People, including myself, have mentioned time and time again _why_ it's a good idea not to fly on less than 100% battery but also point out that a person is probably safe at "90%", "80%, "70%" or another high percentage software guess of the remaining battery but not something much lower.

It's usually also mentioned that the percentage is not the best way to monitor the battery. Watching the voltage in the lowest cell is better.