I was flying my phantom 2 today taking video and was about 9 minutes into the flight. I was showing about 50% battery remaining and I was about 80 meters high and 200 meters away. I started a descent to take a little more video and realized that I had no control. The descent continued until it hit the ground. This is about two months old with maybe twenty flights. I was flying in Phantom mode with GPS. The video shows that the motors were running until it hit the ground, but they did not seem to be at high power even though I had full up pushed on the transmitter. Fortunately the damage is minor, but I had been flying over water earlier in the day.

UPDATE:  I tried it again yesterday and at about 50% power it came down and I could not do anything to recover.  I went and did firmware/software updates and tried again, it did the same thing.  This time just before it landed, I tried to climb and it had very little power.  I used two different batteries and one is brand new.  Both showed about 50% and about ten minutes of flight time.  I was moving it around, not descending in a hover, one flight was calm winds and the other was breezy.

I have this exact same issue,     it does not happen on every flight but it does happen on random flights and random battery levels.    Once the descent starts it can not be stopped by giving full throttle ... it appears that the throttle changes are being ignored.     Once it contacts the ground it then allows the throttle to take it back up again.    Every flight I do now is over soft grass and will be until I get this figured out.    My phantom 2 is also about 2 months old.

I would send them back

Have you tried with different battery? Please connect to the Assistant software, and check the battery information, if the charge cycle is over 20 times, please try a complete charging and discharging. Also, please clean the battery connectors.

I have tried two different batteries.  The first one has 16 cycles and checks good, the second has 4 cycles and checks good. The result is the same.  My failsafe is set to come home not auto land and as I mentioned there is no change in the flashing of the led's when this happens.

ciminojim@hotma Posted at 2014-10-30 22:55
I have tried two different batteries.  The first one has 16 cycles and checks good, the second has 4 ...

I too have used two different batteries and it happens with both batteries

One thing to check is the smartbus data pads on the batteries and clean them with some contact cleaner or alcohol,  also check the spring loaded pins inside the Phantom that make contact with those pads for proper function and clean them as well.

swomilan Posted at 2014-10-30 23:30
One thing to check is the smartbus data pads on the batteries and clean them with some contact clean ...

...I have the same thing happening.  I have three batteries, under 30 cycles each, discharged them all the way down and recharged them, and it still happens every flight.  I get to 52 percent, the rear LEDs flash fast red and it lands.  I can stop the rotors, restart them, get green rear LEDs and fly for less than a minute and then red LEDs and autoland again.  If all I did was fly over soft grass, no problem, but I fly over water a lot and up in the mountains... or at least I did.  Any ideas?  Also, the outer screw on the gimbal gear will not stay torqued and backs off to the point where the camera will not pan all the way down or up without "popping" back about 30 degrees back up.  Any ideas on that?

alan@photostaat Posted at 2014-10-31 00:52
...I have the same thing happening.  I have three batteries, under 30 cycles each, discharged them ...

Alan, might be a defective cell in your battery, heard many reports about that.  Once you have a forced landing connect quickly to the Assistant software and look if one cell pair shows a much lower voltage than the others.

swomilan Posted at 2014-10-31 01:44
Alan, might be a defective cell in your battery, heard many reports about that.  Once you have a f ...

This makes sense. That's probably why they added this bad cell detection feature in this new update..

roelperalta@yah Posted at 2014-10-31 02:48
This makes sense. That's probably why they added this bad cell detection feature in this new updat ...

I highly doubt it is related to a bad battery cell since all the users in this thread who are experiencing this problem  have tried it with multiple batteries and each has said it doesn't matter which battery is being used.

Maybe this is already mentioned,  but check the levels of low battery and critical battery in the assistant program, they are changeable.
If all batteries are doing the same at exactly the same percentage of life, i would suspect sw.

First thing i would try is to change the low battery and critical battery, even if they seems to be correct, just to be sure, so in that case overwrite some bad numbers.

Just a noobs advice

robbin.bergqvis Posted at 2014-10-31 04:59
Maybe this is already mentioned,  but check the levels of low battery and critical battery in the as ...

Definitely worth a try Robbin,  thanks for the suggestion!!!!

Was this with the new firmware that just came out?

michael.haws@gm Posted at 2014-10-30 01:40
I have this exact same issue,     it does not happen on every flight but it does happen on random fl ...

Was this with the new firmware that just came out?

crc2004 Posted at 2014-10-31 06:47
Was this with the new firmware that just came out?

No,  this was with firmware from 6 weeks ago.

This happened with both firmwares. I did the update to see if it would help and it did not, just caused my gimbal to quit. (Another thread) I had two flights today and took the batteries down to 20% without any problem.  Unfortunately, I also fly in the mountains and over water and need to be certain that this is not going to do the auto land.

I purchased a IOSD Mark II and installed it yesterday to see if I or someone could determine from the data of the flight what is causing the autoland.    You can find a copy of the .dat file here :

https://drive.google.com/file/d/ ... VE/view?usp=sharing

You will see that at roughly 80 seconds into the flight the phantom decides to autoland.    I apply full throttle to stop the decent but the motors refuse to respond to my throttle commands.   Phantom strikes the ground at roughly 82 seconds.

Any help appreciated

Ciminojim,  are you still having the problem?

Yes, I still have the problem, but not on every flight.  It seems that if I land before the battery reaches 50%, it is ok.  That is not real practical for me though.  I have not had much of a chance to diagnose it lately as the weather has been pretty bad in the NE.

ciminojim@hotma Posted at 2014-12-3 23:34
Yes, I still have the problem, but not on every flight.  It seems that if I land before the battery  ...

did you made all the suggested solutions like update to the newest FW, bring the batterie under 8%, clean the contacts? are u using genuine DJI batteries?

ciminojim@hotma Posted at 2014-12-3 23:34
Yes, I still have the problem, but not on every flight.  It seems that if I land before the battery  ...

what elevation are you flying at?    And what is the weight of the drone?    Are you using propeller guards?

I believe that the weight is close to 1300g which is less than it used to be when it flew good.  I have tried all the recommendations listed in this thread and have no difference.  I am using factory batteries with very few cycles on them.  I have cleaned the contacts and tried both batteries and have the current firmware.  As I mentioned, I flew this for about 2 months without any issues and this started for no apparent reason.  When this started, there had not been any changes to anything at that time.  I am now afraid to take this out of sight or over water because I do not trust it.

ciminojim@hotma Posted at 2014-12-4 04:48
I believe that the weight is close to 1300g which is less than it used to be when it flew good.  I h ...

I would agree that until you get the trust back you should be very cautious.    For me it turned out to be a weight problem and the newer motors have solved it for me.

I'm curious if you set a home point? If so and it ignored the home point and landed straight down that's troubling to me as most of my flights are over water.

I've purposely ran my batteries down to the threshold set in assistant (20%) just to confirm that the RTH autoland would work. It always has. I test these things when I get a chance to fly over an open field.

I'm not sure if someone mentioned this or not (I'm multitasking) but has this happened in Naza mode?  I honestly don't understand why anyone uses Phantom mode....

I have only used it in Phantom Mode.  For the type of photography we are doing, it works well.  Yes the home point was set and it did not return.  As I mentioned, the battery was still at 50%.  I also had run the battery down low to test it before this happened.  

ciminojim@hotma Posted at 2014-12-4 04:48
I believe that the weight is close to 1300g which is less than it used to be when it flew good.  I h ...

just out of curiosity,   have you tried removing the camera and gimbal to see what that does to your flight time?

Doesn't DJI offer 1 year warranty for the Phantoms? Send it back.

With all the testing you have done, it sounds like a faulty copter - like rzwrey says you should return it.

They tell you to contact your dealer first.  I did that and they have not responded.

I have also experienced this problem the last 2 times I have had it in the air. At first I thought that it was because I was within a lot of wifi interference. But I went to a rural area where I never had any problems before and recreated the problem.

It happens when I introduce a lot of throttle. the back green LEDs would start flashing red quickly which indicates a low voltage situation. sometimes when you let up on the power, it returns back to green. but then introducing more power will cause it to flash red quickly again. I was able to do this even on pitches and rolls at full stick. It all happened on 3 different DJI batteries. If I kept on the stick while the red led was flashing quickly and not let go, the phantom 2 LEDs would stay flashing red and auto land. I still had control of where it would land but the descent was slow  and auto.

At the moment, I suspect it was the cold weather that causes the low voltage warning. I have read that cold batteries don't perform well and lower the C rate thus the low voltage warning at full throttle.

So right now I do not trust my phantom 2. May have to wait for warm weather to see what happens or take a look at the inside of the phantom and see what might cause it.

Cold is no good for LiPo batteries.

swomilan

If it was a defective battery, you would get a message like this.

I have attached to assistant software and batteries are all normal