Unfortunately I'm the next one to suffer a crash after "Propulsion output is limited to ensure safety of battery" appeared in the screen. Air temperature was around 10º Centigrades, wind about 5m/s, battery 45% when the message appeared in the screen. I tried to bring it back and at full throttle the aircraft just flew away from me. Panicked, preshed the Return Home bottom at about 400 meters from me, and the aircraft just disappeared in the sky. Two minutes latter, "Critical low battery level" and landing.

The aircraft (P3 4K) only had 2 months old, about 10 cycles of charge (never bellow the 25%). Latest version of firmware and Android app.

After 5 long hours of search in the middle of the night, finally i was very lucky to find it 1,6Km away from the take off point, body destroyed, camera damaged....

One really strange thing was that, when I started the aircraft that day, it said Firmware update required (even though I have the latest and the place where I was flying from had no internet connexion), and after 30 seconds said Firmware update successful, which is impossible as to update firmware takes much longer, 20-30 minutes. I didn't pay attention to this... Before take off the Aircraft warning message appeared, then after a while said Safe to Fly.

The question is:

-Why the hell was this "Propulsion output is limited to ensure safety of battery" mode activated? (never ever before I saw this, maybe a BUG from the last firmware update?)  

-How on earth the programmers are happy to activate this low power mode in the middle of flight when aircraft is far from you?? It will provoke lots of aircraft losses and potential damage to people and property!  

-And the final one: How could the battery go from 45% to Critical Low Power in only 4-5 minutes?

Sounds like a cold battery was in critical condition, to me...
For a complete drone analysis, Please can you send your flight data to Healthy Drones?

RedHotPoker

I'm very sad to hear this. You have to ensure on take off that the battery temp is at least 20°C.

Very sad to hear this bro, the only thing I can say is that this firmware upgrade message appeared to me also 3 days ago: for the 1st time I got red blinking and beeping RC controller before flight and I just didn't know what to do and there RC upgrade required appeared on dji go app! I have also last FW on both aircraft and controller so this was a surprise to me. After web investigation i've discovered that RC controller required calibration, this was the reason it was beeping. But remains very strange the FW upgrade message that since then i haven't seen any more.

But what can be more appropriate here is that this "propulsion limited message" appeared to me also when i was flying .... and lucky me, after reading what happened to you, i was able to get my bird back {:2_36:} .
Now that i'm examining log files uploaded on healthydrones seems that the propulsion control limit that should trigger on low temperature failed 'cause the battery was pretty warm.
On minute 05.33 battery temp was between 35-40°C and the message "propulsion output limited" triggered... in the panic i pressed GO HOME, and when aircraft was near enough i controlled it manually and successfully hand catched it.

Man, lucky you!  

However!  Now that you said, I did have the same thing with the remote control before that disaster flight!  the remote was blinking and beeping in red for a while and then changed into green.  

I did uploaded the log into HealthyDrones.com and the battery was at 32º C, so that wasnt the reason...  the drone went into warming aircraft in the beginning and then after a while, the normal Safe to Fly

And as I explained you before, it was only when it was already in the air when I did get that message "Propulsions output is limited to ensure the safety of the battery."

To me it sounds like a FIRMWARE BUG....  what do you guys think about it?

" -Why the hell was this "Propulsion output is limited to ensure safety of battery" mode activated? (never ever before I saw this, maybe a BUG from the last firmware update?)  "

This is not a bug, it is a feature added in the latest firmware updates. It is designed to reduce the power to the motors and therefore battery current in cold conditions when the battery may not be able to deliver full power. It can also be triggered by agressive flying, which uses much more power.

"-How on earth the programmers are happy to activate this low power mode in the middle of flight when aircraft is far from you?? It will provoke lots of aircraft losses and potential damage to people and property! "

Calm down. It is designed to protect your aircraft and help guarantee it will have enough battery power in reserve to return to you. When batteries are cold they do not deliver thier rated output, and this can be critical if the aircraft is in the air.

-And the final one: How could the battery go from 45% to Critical Low Power in only 4-5 minutes?

Easily, from 45% to critical is not very far, it could easily drop to critical level in 4 to 5 minutes from a level of 45%. At 45% you should have begun to return to your home position anyway.

And to make it worse, he went to full throttle, the worst thing you can do to a battery that is already low.  From the descriptions of these failures, and the number of them, I'm getting the impression that these batteries become higher impedance as they deplete.  That make sense.  The real question is, why doesn't the new firmware intercept these calls for high current and limit the load to maintain flyability, allowings a certain amount of control.  Having them shut down completely doesn't really cut it.  As someone else said, to hell with the battery, do what needs to be done to allow the quad to be flown to a safe landing.  Common sense says I'd much rather buy a replacement battery than a new drone!

Make the software limit the power, not eliminate it.  The message on the screen should tell you that your power is reduced and to land immediately to save the drone.

And by all means, do not go full throttle when the battery is low, no matter what the temperature.  Set your low battery warning to 45-50%, and don't push it.

AG0N-Gary Posted at 2016-2-22 12:18
And to make it worse, he went to full throttle, the worst thing you can do to a battery that is alre ...

" The real question is, why doesn't the new firmware intercept these calls for high current and limit the load to maintain flyability, allowings a certain amount of control."

That is exactly what the system does, and then warns you using the 'Propulsion power is limited to ensure safety of battery' message. Except the wording is not making it clear that it is actually protecting the aircraft, not the battery. As far as I can recall, no battery has ever shut down, people THINK it did, but it is not what is happening.

The claims have been that the motors stopped and it fell like a rock.  If the current was properly limited, they would continue to run, but at a limited current output so it could continue to make a forced, but controlled, landing.

AG0N-Gary Posted at 2016-2-22 13:27
The claims have been that the motors stopped and it fell like a rock.  If the current was properly l ...

Yes, there was a lot of that happening up until the latest firmware revision that introduced the 'propulsion limitation' function, I have not heard of any since then. But that still does not constitute a 'battery shutdown'.

I have posted several times in the past that I believe a sudden high current demand on the battery can drop the output voltage below the level where the on-board processing circuitry can function. As with most digital circuitry, it will restart when this happens, and during that restart, the motors will shut down. But by limiting the output to the motors, it may stop the voltage dipping low enough to cause a restart.

Any new updates on this issues

ignacioski@gmai Posted at 2016-2-22 05:08
Man, lucky you!  

However!  Now that you said, I did have the same thing with the remote control be ...

It's not a BUG? but it's a useful warning on the Pilot app screen so you can monitor each battery cell  and nurse your quad back home. The first time seeing this message I was flying about a mile line of sight over open water.  The first thing I did was panic and hit RTH but quickly cancel it because the quad will use more power to get up to 100 meters. I also notice this Propulsion warning" only comes on when one or more cells drop below 3.6 volt so I watched each cells keeping them @ 3.6v while slowly flying the quad back to safety..that was the last flight of the day   The video turned out ok too



   

I flew my Phantom 3 Professional on Maui in April 2016 shortly after updating the software to V1.8.80. Prior to this, I completed over 100 flights without any issues. About 12 minutes into the flight, a “propulsion output is limited to ensure the safety of the battery” warning popped up on the DJIGo app. I had never seen this error before the software update. I had no idea what this meant or what to do about it, so tried to troubleshoot and then tried to bring my Phantom home. However, its maximum speed seemed to be reduced by about half even when I was trying to fly forward at full speed. A few minutes later, when the Phantom was about half a mile away (it would have been home at that point if the max speed was not reduced), the battery ran down so far that it auto landed. I tried to recover it but was unable to find it.

The battery had less than 25 cycles and was still under warranty, as was the Phantom. I analyzed the flight record and discovered that after the warning appeared, my max speed was limited by about 40% when the elevator input was at max forward, even though my battery drain rate was unchanged.

This cut my range in half during the last 2-3 minutes of flight, very likely resulting in the loss. I contacted DJI tech support for a warranty replacement and uploaded the flight record as requested. A few months of back-and-forth communication followed, during which DJI attributed the loss to the wind, unforeseen environmental factors, and pilot error. DJI never explained what I had been doing differently from previous flights that caused the “propulsion limited…” warning and stated that the warning in no way indicated a problem with the performance of the Phantom. Ultimately, I filed a small claims suit for the cost of the Phantom and accessories (OEM impellers and battery) that I lost. In court, DJI argued that pilot error caused the loss and that a loss was not covered by warranty because there was no way for DJI to examine the Phantom. However, DJI was unable to explain what pilot actions caused the propulsion to be limited. I argued that I lost my Phantom because it’s range was cut in half in the last 2-3 minutes of flight and that DJI never informed Phantom owners about what could cause this or how to prevent it. I also pointed out that complete loss of the Phantom due to hardware failure was covered by warranty.  The court ruled in my favor and awarded me the cost of the Phantom, accessories, and court fees.

Needless to say, I’m very disappointed that I had to take the time and effort (six months and over 20 hours of my time) to go to court to get warranty service for my Phantom. I can’t imagine buying another DJI product until there’s a drastic change in DJI customer service policies. I should mention that I did ask for DJI feedback  on this before posting, and the feedback was, “we are working on improving both the statement of the warning and our customer service, based on your and other customer’s feedbacks. We are in the process of revising that particular warning involved in this case, for more clear instructions and better wording.”

fansb8355064 Posted at 2016-11-14 17:23
I flew my Phantom 3 Professional on Maui in April 2016 shortly after updating the software to V1.8.8 ...

The message 'Propulsion output etc..' is a badly worded message meaning the temperature of the battery is low and they have reduced the maximum throttle setting in order to conserve battery energy. Although the wording of the message says this is done in order to protect the battery, it is really done in order to protect the aircraft, hence my suggestion that it is badly worded.

This is because when a LiPo battery is operated at a low temperature, it cannot deliver full current without the voltage sagging to a very low level. If the voltage sags too low, the electronics shut down and the aircraft falls from the sky, dead as a maggot. So even though the screen may say you have a certain battery capacity, a cold battery will not deliver anything near that capacity.

The theory in all this is to stop you using too much current and giving the aircraft a good chance of getting back home, at a slower rate. But this does not help if you are fighting a head wind on the return leg, and may result in your aircraft not making it back home. In your case you say the aircraft battery ran down to the point where it auto-landed, so even if the 'propulsion output' or throttle had not been reduced, it most probably would not have made it home anyway.

The intention is honourable on the part of DJI, they are trying to protect your asset, the wording leaves a bit to be desired.