hi.I bought Phantom 3 and made more than 20 flights. All the time were no problems and I am pretty enjoyed of it. But yesterday I made second flight with second battery and it happend I calibrated p3 and the green Safe fly sign. I took off and was around 50 m . The Critically low voltage sign appeared . The aircraft was closed to out of control , anyway I couldn't came back and fly up. I activated return home function but the aircraft was on the way of it landind just on th trees. I couldn't do anything. The battery was not critical and it is in dood condition. It was very closed to be crushed. Phanton landed faraway from me and it was a big success to land safe between trees. But till this time I don't understant what was the reason of this failure????? The temperature was -3 C but it is not forbidden. I don't know is it safe to fly now?? Is it the problem of phantom or battery or application or soft?????if I understand now it can happen any time without any reason and signs.

What percentage was the battery when you took off?
When was the battery charged before flight?

P3_Nutz Posted at 2016-1-24 16:21
What percentage was the battery when you took off?
When was the battery charged before flight?

In this flight 50 % charged few days

P3_Nutz Posted at 2016-1-24 16:21
What percentage was the battery when you took off?
When was the battery charged before flight?

50%
Charged few days ago

Sorry to say - but with -3 degrees and 50% empty you are lucky that it land between trees.
Specially with cold weather use a full battery (charged the same day) and warm it up before flying.

check the temperature of the battery. hover on the ground for arround 2 minutes before flying off and make sure its about 20* before you fly that way it wont get low voltage. basicly if the battery temeperature is low there is a high chance of voltage drop. check it on the battery tab click the battery % on the top left of the app too see the temperature

You should keep your batteries above 20c, by having them inside your jacket.
Also, updating them will improve the built in balance charger and updating your drone will prevent it from takeoff if the battery temp is below 10c
It will also lower max throttle according to battery temperature in order to reduce the massive voltage drops experienced in cold LiPo's.

[RCG]Balthazar Posted at 2016-1-24 20:53
You should keep your batteries above 20c, by having them inside your jacket.
Also, updating them wil ...

Its recommended to only fly on freshly charged batteries.  I have flown at 50% but on the same day I charged the battery and after landing,  powering off and changing locations.

jayredone10@yah Posted at 2016-1-24 14:10
Its recommended to only fly on freshly charged batteries.  I have flown at 50% but on the same day ...

Also note that the battery % can no longer be trusted.
Youre better off looking at the Voltage Levels.

As above, Low temperature and half charged batteries are not a good combination. Always fly on a fresh fully charged battery - even regardless of outside temperature.

But anyway what does it mean this low voltage? The 50 % battery is not empty.

ynazaruk Posted at 2016-1-25 08:44
But anyway what does it mean this low voltage? The 50 % battery is not empty.

It is an estimate of the remaining battery capacity made by the processor in the battery. It is not necessarily perfectly accurate, particularly if the battery is cold. Your aircraft did exactly what it was designed to do. As people have said here several times, do not land then take off again with a partially discharged battery, put a fresh battery in for each flight.