Just lost pro 3 in the ocean.

[MrFus]

To me it's just common sense to have the battery pack fully charged before any flight... I do it on all my devices, from the videocamera that I keep on my hand bag to the pack that I use on my HF portable transceiver, and while the batteries are intelligent that only means that it can monitor internal temperature, voltage per cell, total cycles of charge and manufacture details.

 

[mmtphoto]

You say don't fly over water? What difference would it have made if it dropped from the sky at 150' onto solid ground? My understanding is fly it wherever you want when it's ready to come down it's gone regardless. Sorry for your loss.


Sent from my iPhone using PhantomPilots mobile app

only difference i can think of is if it crashes on land there is a very good chance you can recover it...not so much if it goes into the drink

 

[MrFus]

I have a quick question, did you do the battery calibration on the P3 as you do with the older FC40?

--> ups... I mean adjustments on the voltage settings under Naza software.

 

[chris digata]

Who offers that insurance and how much is it for the inspire?

Ive not read the last few pages of this post but not only should the battery been flown when sat more that 5 hours when at 57% but cell 4 is out of line and looks to me that the battery has not been calibrated.. when did you last calibrate the lipo battery?
On a last note stay away from the inspire as the batteries are more sensitive than the phantom and if not calibrated sooner and kept in trim or even flown hard will fail and a lot more chance of trashing an inspire than a phantom..
if you have the money go for a P4, if you dont have the money go for a p2a as i doubt you even used 4k when 2.7k will do..
On a very last note can i ask how many times has that battery been lower than 5% on the go app display???????

 

[Wibble]

You can get just the bird for a decent price if you look around. Cookie Electronics on ebay puts the full kit P3A on sale on ebay for a really good price of $599. Just gotta keep an eye on it, they just had it yesterday.

Edit:
Wasn't one of the problems with earlier FW versions that when it saw a drop in battery power after starting with less than 100%, it would shut off the motors?

That was one of the middle updates. Mine is earlier than that. The later ones just reduce power. Mine just allows a temporary voltage dip - much more sensible!

 

[bryan_m]

New pilot.. Do not take off with less than a fully charged battery. Just don't. My experience on over 100 flights with the P3 has been nothing short of amazing. I completely trust the bird.. One time I took off with a batter I thought was fully charged. I thought the percentage displaying was my tablet charge. It was not. I launched flew about 5 minutes and received a warning about remaining battery. This was a battery that I had flown down to 50% a few days prior. Even at 50 percent charge is should not have been at 12% after only a few minutes flying. It is really apparent that the battery doesn't properly display available charge after it has been sitting. Especially if it enters into the auto discharge state. So... Charge it to capacity fly it. Do not fly a battery that has been discharged most importantly do not fly a battery that has entered auto discharge.

Can someone elaborate on the reason not to fly after a battery has started its auto discharge state? I never had this on the P2 so it's sort of new. I have noticed that twice I was out with what seemed to be a 'full' battery when checking the battery but after connecting it to the app found out that it was in the mid to high 80's percent wise. I still flew since there was more than 19mins of flight time calculated but both times it seemed to deplete at the 35% mark very quickly (going from 5mins flight time down to 2mins in about a minute time). Both times it was an easy land for me as I already had it close and was flying conservatively but it sort of question either the battery or the method of calculations.

 

[Mark The Droner]

Can someone elaborate on the reason not to fly after a battery has started its auto discharge state? ...

Because our aircraft will crash and burn.*


*It actually probably won't crash and burn but we've learned the risk of it crashing and burning is significantly higher than when using a freshly charged battery and we're smart enough not to tempt fate.

 

[Mark J Colbert]

Sorry for your loss. I fly mine over water all the time. In fact, at 5,365 ft, the farthest I've ever flown away from the controller was over water:

or

. I've lost the signal and always had it come back to where we started. When the low battery alert comes on, we are done flying on that battery. I bring it back, throw another fully charged battery in it and the fun continues. If I never fly with an undercharged battery, I never have to worry about explaining to my wife what happened to my Christmas present she saved up for.

 

[Mark J Colbert]

Sorry to hear about your drone. I just lost mine last week, from being stupid and attaching a fishing line to it. Crashed into the bay, and never was seen again.
Amazon has the DJI drones and interest free payments for a year. That's the only reason my wife let me get a new one.

You can get the flight records from the dji go app, even if you the drone was lost.

Let's first establish that the way in which the camera is facing is North and the battery is on the South side of the aircraft. I've taken a piece of an old golf club handle, 18 inches long, zip-tied it across my West-facing landing gear North to South. 10 inches of the carbon fiber handle protrude out in front of the drone. When I go fishing, I take my lure (I'm fishing for Bass and Trout in a lake) and carefully drape it around the aircraft (from South to North) and hang it over the part of the handle sticking out in front of the drone. When you take off, the lure will be dangling over the handle, not tied to - or secured to, any part of it. I release the bail on my spinning reel so that the line is free to unwind, and take off to around 15-20 feet in elevation. When I get to the point of release, I simply stop the drone, slowly rotate it counter-clockwise and back it up, the line/lure slides off the handle and drops perfectly. I tried this 10 times in my yard and a park before I went out over water to get the feel for how it would work. I NEVER get in a hurry and NEVER take a chance on getting the line caught or hooked onto the handle or my landing gear. If anything looks bad, it comes home right away and we try it again. Using this technique, you can very accurately place your lure or bait 50, 60, or even 100 yards away - with no weight. Other fishermen around you will be amazed and want you to cast for them also.

 

[Mark The Droner]

...

You might want to check this thread out which is in the off topic forum... Drone Fishing

 

[Vertigo]

Looking at the flight data, the OP took off with a battery that had ~3.6v per cell. Thats past the voltage I land my other planes/quads/etc, because the battery is mostly depleted at that point, especially if that is not under high load. The minor variation between the cells is not a big deal, the lower the voltage, the bigger those discrepancies become because the remaining capacity is close to zero for all cells. To illustrate with an exaggeration, if one cell would be a 2.5v and thus say 0.1% remaining and the other at 2.7v and 0.2%, you may say thats a big difference, but its only 0.1% of their capacity and not an issue (other than you'd kill both cells going so low).

Anyway, the phantom and thus the app 'knew' those low voltages, because thats where we are getting the log from. Yet for some weird reason, that depleted state is reported as 57% Thats what he supposedly took off, and crashed with 56% when in reality his battery was beyond empty approaching 3V per cell.

I dont see how anyone can put the blame with the OP. Thats a serious problem, and one that is all the more unforgivable considering the excessive price we pay for these "intelligent" batteries.

I do thank the OP for posting this and bringing it to my attention, so that I make sure not to trust the battery capacity indication. I hope the voltage indications are correct, so I can go by those. I would also advice you to contact DJI. This is not your fault, its theirs.

 

[Mark J Colbert]

I've seen that one. Very cool. They use a quick release system which is triggered when the fish takes the bait; the same type of release used with downriggers.

 

[JasonJett]

Looking at the flight data, the OP took off with a battery that had ~3.6v per cell. Thats past the voltage I land my other planes/quads/etc, because the battery is like 95% depleted at that point. The minor variation between the cells is not a big deal, the lower the voltage, the bigger those discrepancies become because the remaining capacity is close to zero for all cells. To illustrate with an exaggeration, if one cell would be a 2.5v and thus say 0.1% remaining and the other at 2.7v and 0.2%, you may say thats a big difference, but its only 0.1% of their capacity and not an issue (other than you'd kill both cells going so low).

Anyway, the phantom and thus the app 'knew' those low voltages, because thats where we are getting the log from. Yet for some weird reason, that depleted state is reported as 57% Thats what he supposedly took off, and crashed with 56% when in reality his battery was beyond empty approaching 3V per cell.

I dont see how anyone can put the blame with the OP. Thats a serious problem, and one that is all the more unforgivable considering the excessive price we pay for these "intelligent" batteries.

I do thank the OP for posting this and bringing it to my attention, so that I make sure not to trust the battery capacity indication. I hope the voltage indications are correct, so I can go by those. I would also advice you to contact DJI. This is not your fault, its theirs.

It looks like dji has taken the responsibility of this flight and saying that I was at no fault. However they said because I don't have original proof of purchase they are not going to replace or give a discount on a future device. I do have once employee contacting management on Monday. Nothing is promised but hopefully I will get some relief. I get the hard spot they are in but this drone was clearly purchased and clearly had a issue. I hope they help with something.


Sent from my iPhone using PhantomPilots mobile app

 

[WetDog]

Looking at the flight data, the OP took off with a battery that had ~3.6v per cell. Thats past the voltage I land my other planes/quads/etc, because the battery is like 95% depleted at that point. The minor variation between the cells is not a big deal, the lower the voltage, the bigger those discrepancies become because the remaining capacity is close to zero for all cells. To illustrate with an exaggeration, if one cell would be a 2.5v and thus say 0.1% remaining and the other at 2.7v and 0.2%, you may say thats a big difference, but its only 0.1% of their capacity and not an issue (other than you'd kill both cells going so low).

Anyway, the phantom and thus the app 'knew' those low voltages, because thats where we are getting the log from. Yet for some weird reason, that depleted state is reported as 57% Thats what he supposedly took off, and crashed with 56% when in reality his battery was beyond empty approaching 3V per cell.

I dont see how anyone can put the blame with the OP. Thats a serious problem, and one that is all the more unforgivable considering the excessive price we pay for these "intelligent" batteries.

I do thank the OP for posting this and bringing it to my attention, so that I make sure not to trust the battery capacity indication. I hope the voltage indications are correct, so I can go by those. I would also advice you to contact DJI. This is not your fault, its theirs.

"We" have long known that the percentage figure on the app is nonsense, hence the multitude of recommendations to put the voltage up on the screen and know what it means.

That said, DJI is being typically schizoid about this. It markets the Phantoms as easy to use, no detailed knowledge needed and then tries to dumb the system down without doing the requisite engineering. That's where DJI screws up time and time again. These things are still pretty complex. Not iPhone level of user friendliness by any means.

Fine by me, I can read and enjoying tinkering around with things. For others, not so much.

 

[AJAX-14]

Why take any risk? I mean really? DJI clearly warned us long ago that battery performance is not reliable/predictable if you take off with a less than fully charged battery. Lesson: Always charge your batteries to 100% before flight. If we don’t adhere to that recommendation, DJI isn’t liable.

It’s just a reasonable assumption. We all know, a car, a flashlight, or our Bluetooth speakers, will power on with a depleted battery. But the car may not start, and the other devices will not operate long. That is the nature of the battery physics and has little or nothing to due with operating temperature, altitude, atmospheric pressure or solar flare ups.

Sitting idle the Voltage (E) is static at the rated E of the battery. However, as the charge is depleted the Current (I) the battery can deliver is drawn down, below the rated Power (P - which is E x I). As we draw (accelerating) on the battery I increases, E decreases. But a battery will generally ALWAYS indicate its rated E until it is asked to deliver I.

Looking at the log, it’s obvious the quad lifted off with 56% battery P and 100% E. However, it quickly depleted to 88% E as the pilot accelerated. At 2:04 flight time accelerating out to sea, the I drew the battery below nominal operating P.

What is more curious, and should clearly be investigated by DJI is the fact the battery indicator continued to read 56% (assumed P) even though the E dropped below 88%, and below the apparent minimum operating voltage for the motors (12V). May not have helped in this case since the time from TO to failure was only 2:00 minutes.

 

[Mark The Droner]

...
What is more curious, and should clearly be investigated by DJI is the fact the battery indicator continued to read 56%....

<sigh>

 

[Vertigo]

It’s just a reasonable assumption. We all know, a car, a flashlight, or our Bluetooth speakers, will power on with a depleted battery. But the car may not start, and the other devices will not operate long. That is the nature of the battery physics and has little or nothing to due with operating temperature.

I expect my car to start and drive when the fuel indicator indicates 50% fuel (or 50% charge in the case of an electric car). The indicator doesnt have to be perfect, if I keep driving with a warning light, I'll take the blame, the estimated range may be off, but If it stalls on the highway with an indicated 50% capacity, I blame the manufacturer, not the driver for not fueling or charging his car. OP never even got a low battery warning.

Sitting idle the Voltage (E) is static at the rated E of the battery. However, as the charge is depleted the Current (I) the battery can deliver is drawn down, below the rated Power (P - which is E x I). As we draw (accelerating) on the battery I increases, E decreases. But a battery will generally ALWAYS indicate its rated E until it is asked to deliver I.

You are confused or confusing. No battery will deliver nominal voltage when its depleted, even with no load. Take any empty lipo battery, and you will get something like 3.2v per cell, no where near 4.2. The opposite is just as true, if your lipo battery delivers 4.2V with no load, its fully charged, always. It may be faulty, but its as full as it gets.

Now voltage will sag when under load, that is true. Voltage under load therefore doesnt correlate directly with capacity. But especially on a quadcopter, that load is fairly constant and predictable. Not only that, the load is actually measured and the voltage sag is known and taken in to account. A simple voltage reading needs context; 3.8v at rest is only half full, 3.8 under high load might be a full battery. But that is why we typically dont get to see voltage, instead a calculated value. Its like that with just about everything, including your phone. Which I bet, doesnt suddenly turn off even though it says 50% battery left. In this case, it was WAY off.

Looking at the log, it’s obvious the quad lifted off with 56% battery P and 100% E.

What are you talking about, "100% E" ? His cell voltage on take off was ~3.6v. Thats no where near fully charged, even under maximum load. If it was, then the battery has an inadequate C rating. A fully charged battery is 4.2v per cell. That may sag to 3.9 or so under peak load. Not 3.6. He took off with a nearly depleted battery, and for some reason, the software didnt read it as such, even though anyone could tell just by looking at the same voltage values that the software saw.

What is more curious, and should clearly be investigated by DJI is the fact the battery indicator continued to read 56% (assumed P) even though the E dropped below 88%

Thats in no way weirder than indicating 56% for a battery that couldnt possibly have that much capacity left.

 

[impilot51]

"But especially on a quadcopter, that load is fairly constant"

I would tend to disagree with this statement. Perhaps at a constant hover, yes. But under a hard climb while accelerating you will have a significant change in load. Which if that load is too much, the battery cuts out. End of story.

All the arm chair electrical engineers crack me up. Vendor says, charge before you fly. We see plenty of cases (especially on one specific firmware release that was buggy), lots of unexplained, mysterious falling P3s. Then we get plenty of reports of erroneous readings when taking off with partially charged batteries. And yet, a segment still wants to argue that the battery should not do that! Sorry, but the evidence speaks to the contrary. Get over it. Charge before you fly or tempt the battery Gods to come out of hiding and smite your P3!

 

[Vertigo]

Of course load varies even on a quadcopter, but its a lot more constant and predictable than say an airplane. Or for that matter, a car - since quadcopter dont tend to fly very well or long with near zero load, a plane will. And prolonged periods of 100% throttle is also more exception than rule, for obvious reasons. If you deplete your battery by only climbing, you have a big problem.

And as importantly, just about the only variable is your throttle position. On a plane airspeed is a big factor as well, as it will draw far more current at full throttle on the ground than it will full throttle in a dive. Prop stall is another factor you dont have to contend with. Thats why I said its relatively easy to calculate for a quadcopter; if you know the voltage and the throttle position(s), you should be able to work out a good estimate of battery capacity for any given battery type*. If you measure the actual current draw, as Im pretty sure the phantom and every similar multirotor does, the estimate should be close to perfect.

* And we only get to choose 1 battery, so thats another thing to make it easy.

(by throttle position(s), I dont mean the one on your controller, I mean the ESC setting of each motor)

 

[AJAX-14]

Unless we know the actual measurements taken and the algorithms DJI uses to calculate battery use and condition, it's pointless to make assumptions on how battery management is accomplished. I was merely stating electrical fact (Ohm's Law), current and voltage are conversely proportional and their product is power (load).

The DJI battery is rated at 15.2V (or 3.8V/cell) nominal, not actual. The OP log indicates battery condition at TO was 15.387V and average of 3.85V/cell. His battery was at nominal operating voltage at takeoff.

You have basically said he same thing I offered in my post. Varying the voltage (ESC setting) thousands of times a second on four motors simultaneously to maintain attitude, altitude and heading produces a varying load and current on the battery source during flight. Accelerating and climbing greatly increase the load and the current, so the only factor left is voltage, mathematically it has to drop.

I expect my car to start and drive when the fuel indicator indicates 50% fuel (or 50% charge in the case of an electric car). The indicator doesnt have to be perfect, if I keep driving with a warning light, I'll take the blame, the estimated range may be off, but If it stalls on the highway with an indicated 50% capacity, I blame the manufacturer, not the driver for not fueling or charging his car. OP never even got a low battery warning.



You are confused or confusing. No battery will deliver nominal voltage when its depleted, even with no load. Take any empty lipo battery, and you will get something like 3.2v per cell, no where near 4.2. The opposite is just as true, if your lipo battery delivers 4.2V with no load, its fully charged, always. It may be faulty, but its as full as it gets.

Now voltage will sag when under load, that is true. Voltage under load therefore doesnt correlate directly with capacity. But especially on a quadcopter, that load is fairly constant and predictable. Not only that, the load is actually measured and the voltage sag is known and taken in to account. A simple voltage reading needs context; 3.8v at rest is only half full, 3.8 under high load might be a full battery. But that is why we typically dont get to see voltage, instead a calculated value. Its like that with just about everything, including your phone. Which I bet, doesnt suddenly turn off even though it says 50% battery left. In this case, it was WAY off.



What are you talking about, "100% E" ? His cell voltage on take off was ~3.6v. Thats no where near fully charged, even under maximum load. If it was, then the battery has an inadequate C rating. A fully charged battery is 4.2v per cell. That may sag to 3.9 or so under peak load. Not 3.6. He took off with a nearly depleted battery, and for some reason, the software didnt read it as such, even though anyone could tell just by looking at the same voltage values that the software saw.



Thats in no way weirder than indicating 56% for a battery that couldnt possibly have that much capacity left.