I've been reading some threads lately with low batteries causing sudden falls, etc...
I'm a bit confused with the two warnings, and what they each really mean - and how the aircraft will react to each of them.
So my questions are:

1) What does low battery warning mean in terms of aircraft reaction? And what do you have yours set to?

2) What does critically low battery warning mean in terms of aircraft reaction? And what do you have yours set to?

Thanks in advance!

I set low battery warning at 30%. This will warning you that your battery is low and you should take it home and land it. This level of warning won't do anything to your phantom.
I set 10% critical battery. At this point your phantom will land it by itself.
In case you fly far distance, the return home level will be variable depends on how far your phantom is so the phantom will return home when that level has been matched

Warnings set to defaults (30 and 10%).  It will autoland wherever it is at 10%  (avoid this).

So just to confirm, at 10% it will auto land wherever it is - I will have NO control over this to even override?

And let's say I'm long ways away from home point, will at any point the aircraft attempt to return to home automatically ?

KM5RG-Robert Posted at 2017-3-24 19:46
Warnings set to defaults (30 and 10%).  It will autoland wherever it is at 10%  (avoid this).

I was testing ours this afternoon, and it started beeping at the default 30% warning, and that just seems annoying. I flew it around the ground to see how long it would take to drop 10%, and it took several minutes to even get to 20%.

So  I went ahead and dropped it to 22% to test, because you can book it home in 10-12% before it's forced to auto-land imo.

fans5638ab28 Posted at 2017-3-24 20:05
I was testing ours this afternoon, and it started beeping at the default 30% warning, and that just seems annoying. I flew it around the ground to see how long it would take to drop 10%, and it took several minutes to even get to 20%.

So  I went ahead and dropped it to 22% to test, because you can book it home in 10-12% before it's forced to auto-land imo.

Did it actually AUTO LAND at 10%? Or did you not get it that far?

I'm fairly cautious. I haven't changed default settings. If I fly far out, I do it right after launch on a full battery. I'm usually landing by the time I get any warnings.

DroneSmeg Posted at 2017-3-24 20:49
I'm fairly cautious. I haven't changed default settings. If I fly far out, I do it right after launch on a full battery. I'm usually landing by the time I get any warnings.

Steady as she goes Dronesmeg.  

Yup usually I prefer to land with more than 20%.  

Low battery warning is just a warning, the aircraft will not react.

Critical Low battery warning is when it starts to auto land where it is, it will not return home.  You can still use the controls to adjust it's position to a safe landing place and can use throttle up to delay the landing a little.

Low battery return to home is a separate feature which will fly it home before reaching critical low battery unless you cancel it.

I have both values set to minimum, but I normally fly within sight so when the warning occurs I still have time to fly back before reaching critical and I also normally stay within our 400ft legal height limit so 10% is always plenty for landing.  Also I have a P4, nearly all the battery problems being reported are on the P3, I would use higher values if I had a P3.

If I am photographing a sunset, maybe doing a timelapse then I will sometimes leave it hovering directly above the take off point, in that case I will sometimes leave it up there until it reaches critical, it then always auto lands at the 10% critical setting without problems.

meedz24 Posted at 2017-3-24 20:23
Did it actually AUTO LAND at 10%? Or did you not get it that far?

I have tested it. Aircrafts AUTO LAND at <10%. You still have control over it, but it will automatically drop altitude. By pushing altitude stick UP You can only set aircraft at current altitude (but not higher!). When You let go this stick, aircraft will continue to drop altitude till it lands.

Yes  This means you can fly it home while in auto-land.  I have a friend who has successfully flown home from well over a mile away while in auto-land.  

Edit:  keep reading...

Mark The Droner Posted at 2017-3-25 03:02
Yes  This means you can fly it home while in auto-land.  I have a friend who has successfully flown home from well over a mile away while in auto-land.

I think you should have said "Yes, this may enable you to fly it home..."

At some point it will run out of power, once you are below 10%, if you delay the landing then you are taking a risk!  Although I think there is another warning when it is almost at zero, maybe that one disables you from preventing landing by using throttle up?

Yes, you're right.  You may be able to fly it home or you may run out of power before you make it home and your AC will drop from the sky.  Although the battery may provide power all the way down to 0%, it's also possible it could simply shut itself off before then for a variety of reasons.  You're definitely taking a risk attempting to fly it home while it's in auto-land.

Mark The Droner Posted at 2017-3-25 03:34
Yes, you're right.  You may be able to fly it home or you may run out of power before you make it home and your AC will drop from the sky.  Although the battery may provide power all the way down to 0%, it's also possible it could simply shut itself off before then for a variety of reasons.  You're definitely taking a risk attempting to fly it home while it's in auto-land.

I suggest some people read these threads  critical battery warning at 35%

http://forum.dji.com/forum.php?m ... 01&page=1#pid736184

Deep cycle for battery

http://forum.dji.com/forum.php?m ... mp;page=1#pid741802

30% for low, 10% for critical. I usually land at 25-30%, don't wanna take any unnecessary risks.

fans5638ab28 Posted at 2017-3-24 20:05
I was testing ours this afternoon, and it started beeping at the default 30% warning, and that just seems annoying. I flew it around the ground to see how long it would take to drop 10%, and it took several minutes to even get to 20%.

So  I went ahead and dropped it to 22% to test, because you can book it home in 10-12% before it's forced to auto-land imo.

What if you are flying against the wind? I don't want to end up with a crashed drone. Would you want your pilot on a passenger airplane to always run the tanks low just because he thinks he can? But do as you wish.

Nigel_ Posted at 2017-3-25 00:10
Low battery warning is just a warning, the aircraft will not react.

Critical Low battery warning is when it starts to auto land where it is, it will not return home.  You can still use the controls to adjust it's position to a safe landing place and can use throttle up to delay the landing a little.

"low battery return to home" - is this something that is already set? Or do I need to enable this somewhere?

I've left the settings at default.
Use the skinny line with three colours at the top of the Go App to give a guide on when you should go home. If you manage your batteries well, that's usually pretty accurate

meedz24 Posted at 2017-3-25 16:56
"low battery return to home" - is this something that is already set? Or do I need to enable this somewhere?

It is automatic and can't be turned off on the P4.  You can cancel it when it activates if you wish, not normally a good idea but it is pessimistic about wind conditions etc. so if you are careful then you can fly for a fair bit longer if you cancel it.

meedz24 Posted at 2017-3-24 20:23
Did it actually AUTO LAND at 10%? Or did you not get it that far?

Yes, it auto-landed.  

I was just flying it about 5 feet off the ground around me, so if it didn't it wouldn't drop out of the sky, haha.

Worked well actually.

Hi Guys,

See this:

http://g1.globo.com/sao-paulo/no ... ta-veja-video.ghtml

The P4 landed after 10% of battery.

I have set the low battery warnig to 20% because I fly in range of sight (German rules) and I had never reached 10% capacity by now.

KM5RG-Robert Posted at 2017-3-25 15:29
What if you are flying against the wind? I don't want to end up with a crashed drone. Would you want your pilot on a passenger airplane to always run the tanks low just because he thinks he can? But do as you wish.

You fly against the wind on your first part of the flight and return with a tail wind.

If you fly with the wind you will end up having to land somewhere as you will not make it back if the wind is too strong.  Always have an alternative landing area plotted.

blackcrusader Posted at 2017-3-28 00:17
You fly against the wind on your first part of the flight and return with a tail wind.

If you fly with the wind you will end up having to land somewhere as you will not make it back if the wind is too strong.  Always have an alternative landing area plotted.

Yes.
I was answering another post with a question.

KM5RG-Robert Posted at 2017-3-24 19:46
Warnings set to defaults (30 and 10%).  It will autoland wherever it is at 10%  (avoid this).

In anyways at 10% the "wherever" should be very close to RTH.

Keep in mind the "Percentage Remaining" is a calculation. This calculation lags actual battery voltage, which should be the driver behind the decision to continue flying or to land.

Battery percentage can and will drop by multiple percent based on the calculation mentioned above. (eg. The percentage may be 15%, on its way home, and the aircraft encounters a headwind causing voltage to drop to a commensurate 10% and your aircraft begins landing)

Moral to this story: It is not best practice to be very far from home with your battery percentage below 25%-30%