low voltage warning - Auto-landing without warning

[clicari]

I recently flew my P3P a few weeks after previously fully charging both batteries. Charge indicators showed less than full but voltage was fine. about thirty seconds after takeoff I received a low voltage alert. I promptly turned around to return home at full speed. Progress was being monitored on my iPad and before I realized it was forcing a landing it drove straight into heavy tree branches shearing the camera off completely as well as other damage. Being a low time drone pilot (many hours of RC heli time) my question is why is there no warning of eminent landing, in which case I wouldn't have tried to get home first? The drone is probably a total loss due to cost effective repairs considered. Sad because body is completely intact. Might need one motor but the camera and gimbal costs will likely be too expensive.
TIA
Carl

 

[msinger]

Would you mind sharing your TXT flight log so we can check out the details of your flight? If that's okay please upload it here and post a link back here.

 

[Fly Dawg]

my question is why is there no warning of eminent landing, in which case I wouldn't have tried to get home first?

As @msinger mentioned above, we will be able to tell you more from the flight logs. In answer to the question quoted, is, that depends. A low battery alert is only a notification that you need to return and land. There is also a second notification " Critical Battery". At that point the AC will auto land and it does notify you of that. This all depends on where you have your battery levels set to as to when you get these notifications. There are settings for both in the app. Again, we would need to see the logs to verify anything for you.

 

[Neon Euc]

Sorry to hear about what happened. Thankfully it sounds like you just need a new camera arm and a ribbon cable to get it working again. Shouldn't cost no more then $80 in all honesty.

It seems like the drone had two choices on low voltage. To land slowly or cut off in the air. Despite the fact your camera snapped off I think you got pretty lucky [emoji4]

It happens to all of us at some point no matter how good we are, electronics can never be 100%

As mentioned do upload the DAT file so the pros can have a look. Just out of interest.... Was the battery a 3rd party one?

 

[clicari]

Log uploaded...and I think I got my answer.
Battery was a DJI. The camera has a shattered front element that will not screw off, even with channel locks! I'd love to get it fixed. I'n Denton, TX Any help would be appreciated. It was a friend's drone that passed away and hate to lose it.

 

[msinger]

Log uploaded

Please post the link here.

and I think I got my answer

What's the answer?

 

[clicari]

Here is the log

 

[Oso]

Here is the log

Here's the uploaded flight log link. Looks like a launch with a very low battery and the critical low / aircraft landing warning came at :57.2

DJI Flight Log Viewer - PhantomHelp.com

 

[msinger]

Here's your uploaded log file:
DJI Flight Log Viewer - PhantomHelp.com

It shows the battery reached the critically low level because you were putting too much stress on a battery that was already too low to be usable for a normal flight.

 

[clicari]

Battery showed half charged and voltage within limits. I was just hoping to get a deep cycle recharge, but I've learned my lesson, the hard way.
Anyone have any suggestions on repairs? TIA
Carl

 

[Fly Dawg]

Below are the Individual Battery Cell Voltages, and the Overall Battery Voltage. They are way out of limits. Also noted, you did receive an "AUTOLAND" warning at 57.2 Seconds. ( 3.2v per cell is absolute minimum and cutoff point)

 

[msinger]

Anyone have any suggestions on repairs?

You can find some repair shops here.

 

[JMFinch]

I had a fully charged after market p3p battery throw a low voltage warning at 42 seconds and descend into the treetops as i held the stick at full throttle.

 

[BigAl07]

I recently flew my P3P a few weeks after previously fully charging both batteries. Charge indicators showed less than full but voltage was fine. about thirty seconds after takeoff I received a low voltage alert. I promptly turned around to return home at full speed. Progress was being monitored on my iPad and before I realized it was forcing a landing it drove straight into heavy tree branches shearing the camera off completely as well as other damage. Being a low time drone pilot (many hours of RC heli time) my question is why is there no warning of eminent landing, in which case I wouldn't have tried to get home first? The drone is probably a total loss due to cost effective repairs considered. Sad because body is completely intact. Might need one motor but the camera and gimbal costs will likely be too expensive.
TIA
Carl

The DJI batteries are programmed (via DJI Go App) to start self discharging after X-# of days. I think the factory default is 1 0days (someone correct me if that's wrong). After X-# of days the battery's internal circuitry starts a slow but steady and safe auto-discharge. The problem is a sitting battery that has been discharging may not give an exactly accurate reading when it's sitting/idle. The problem is you might get a "Flyable" battery level at first but when you put it under a load (the higher the load the more dramatic the variance could be) it can quickly go to low and even critical levels. This is why so many people suggest (and without knowing exactly why) to never fly with a battery that is showing less than 90% charge.

I had this EXACT same thing happen but it was with a battery that had a faulty cell. I took off with a FULL charge and at 80% it started giving battery warnings and then went into Critical Battery warnings and initiated an auto landing. I knew it couldn't make it "home" so I headed for a landing spot (I was over water in a lake).

 

[Meta4]

Charge indicators showed less than full but voltage was fine.

If you are using a partially discharged battery, the % indicator will not give a true indication of battery strength.
In this case you launched with it showing 44% but within seconds of takeoff, the battery was down to <3.3V per cell which is not safe for flying.

 

[tcope]

about thirty seconds after takeoff I received a low voltage alert.

Okay... you were given a warning of low voltage.

my question is why is there no warning of eminent landing, in which case I wouldn't have tried to get home first?

You were and the manual explains this. You also still have partial control of the Phantom and can move side to side.

Batteries at rest will show a higher charge. Once you put a large load on them, they will dip in voltage. This is why DJI recommends that you start the flight on a fully charged battery.

 

[YU6MM]

You must keep battery warm. Its happened to me also and i canceled auto landing with several times puling left stick up. My Phantom was outside on cold wind for about 3 hours and battery cells lose capacity. Battery was on 93%.

 

[Irv Sper]

If you are using a partially discharged battery, the % indicator will not give a true indication of battery strength.
In this case you launched with it showing 44% but within seconds of takeoff, the battery was down to <3.3V per cell which is not safe for flying.

I have a phontom 4 drone and it has had the same issues all winter long. Everything is new as of a month ago.. Even on the warmer days at about 45 degrees. I never fly my drone with out a fully charged battery. Directly off the charger. And I have two batteries. Still.... with different batteries its the same thing. Within about a minute ......five minutes.... or at any time. It warms me the batteries are low. And starts to land on its own. Ive continued to over- ride it..and just looked for a safe place to land as quick as possible. Never had an issue with crashing it yet. So... whats the real cause for the warning and .....out of the blue.... "aircraft " landing ????

 

[Meta4]

I have a phontom 4 drone and it has had the same issues all winter long. Everything is new as of a month ago.. Even on the warmer days at about 45 degrees. I never fly my drone with out a fully charged battery. Directly off the charger. And I have two batteries. Still.... with different batteries its the same thing. Within about a minute ......five minutes.... or at any time. It warms me the batteries are low. And starts to land on its own. Ive continued to over- ride it..and just looked for a safe place to land as quick as possible. Never had an issue with crashing it yet. So... whats the real cause for the warning and .....out of the blue.... "aircraft " landing ????

It sounds like either:
You have changed the default low battery level or
Something isn't quite right about the battery.
Check your battery limit settings in the app (default low battery warning level is 30%)
If that's right, check flight data as in post #2.

 

[clicari]

Thanks to everyone for the well taken advice. Batteries will be fully charged in the future.
I have rebuilt the P3P, replacing the flex cable and a new gimbal arm piece. It's aback together and working and flying well, except for one thing, I have no image signal to the iPad. I believe the camera is working because if I block the lens the ISO goes to a higher value to compensate for less light. I've taken the back plate off the camera to double check the board for damage and the cable for proper seating. I have flown it several times with different batteries, tried my iPhone as well as the iPad. Anyone have any ideas?
TIA
Carl