Phantom 3 Professional Battery Failure when I was over 50% battery level

...I have 6 batteries and charged all prior for the day run, ...
How did you have six batteries almost 3 weeks ago, when almost no one had more than a single battery until very recently?
 
Maybe has other quads and forgot to mention that.
 
I don't see that flying over water had anything to do with the problem. I fly over water almost every time out.
I'd guess this incident was caused by an improperly seated battery.
I don't exactly slam my battery in, but I do give it a fairly good "pop" into the chamber.
 
"sure, he has 6 Phantom3's"

Huh???
 
I truly feel for you. I may still be able to find mine, launching a expedition this Sunday to look for it at the bottom of the lake. View attachment 21610

I have had a similar experience with my p3pro. I was at lake Powell and while flying over a few feet of water I heard landing, landing, landing. I attempted to get a return or movement away from the water without success. After some e mail negotiations I settled by paying over $800 to get a new one. I unfortunately am a slow learner and after reading about flight logs I checked mine. I found out the drone had 22% battery when it landed.

I have contacted DJI and asked them too re-open my file with the finding. I am anxious to see their answer.
drone picture fall.jpg
 
let me add an afterthought . the battery was seated. when I recovered the drone it was hard to pull out. the battery after recovery was dead. Don't know if it died before or after it landed in water. the above picture shows most of the flight was over water. Actually it was mostly over land
 
If not a poorly inserted batt, my belief the next likely cause is a bad cell or even a dumb *** smart battery. I say this off my experience with 3 P2's and soon to be P3 pilot. And of course we are going to fly over water, we fly where the beauty is. My favorite is the nudist camp or White House lawn (kidding). All 3 of my P2's have severe crashes due to the failure of the battery as described above. The most recent this week gave me some ideas to research. As before on the previous 2 battery failure crashes, battery was firmly inserted and this time was hovering only a few feet from me for the purpose of running batt down to approx 50-60% since I had not used it on the weekend and may be weeks before using again. All normal until 79% and 11.1v**, suddenly it went to 10%-10.8v, batt icon was empty and flashing, red LEDs flashing and going down fast. Being close I reached to catch and just as quick the voltage shot back over 11v, didn't notice what the percentage was with the chaos, but everything returned to normal seemingly. As I stepped back it immediately went back to before with batt now showing 10.6v and less than 10%, as I caught it I continued to apply power to watch the battery readout. It would alter between a reading of 11.1 or .2 or .3v running strong, to 2-3 seconds later back to 10.4 and falling, with motors going to auto land. Each time the batt icon would show 3/4 full to blinking empty. The back and forth almost seemed like a loose connection with the abruptness of the changes, but now each swap in v readings on the lower end keep getting into the range I thought this thing would not do. It hit 9.8, 9.6, 9.3v and somewhere along here the motors finally shut off. I charged it back up later and after the second flashing light went to solid green, it stopped charging, but pressing the batt button shows a full charge. One of the other failed batt did the same after reaching the third solid green light, can't remember details of the first batt. The Assistant SW showed no indication a problem with the batt, but the cell voltage readings were off a little; 1 3880 2 3815 3 3879. This mean anything? Today I will remove the cells, and try to rebuild using the best cells from my P2 batt infirmary. I'm not sure how to pick the best or identify the bad ones, they all are reading close in volts (smart cap problem?)

With amount of money invested in the pricier drones, in my opinion the battery does not give me the confidence I need my investment will come home tonight (like my ENRON investments). I wonder if a electronic device that can automatically kick in with a batt failure with just enough batt juice to get something like a P2 or 3 say an extra 50-100' for an emergency landing. But thats added weight and cost, plus you add another failure potential. I like the idea though.
**Some values I am not 100% correct, but it definitely got down to the low 9s, thought it shouldn't;t even run that low.
 
Several people on this thread stated you should post the video, but it is my understanding that the only thing you have left after an accident is the flight path information. The video and photos are not on the table, only on the SD card. Am I correct? I know it is different if you are "live streaming" but for most flights the video and stills are only available if you can get the micro SD card.

There are ways to "transfer" from the SD card to the tablet, but that takes quite a while and is not practical during an actual flight.

If you have video caching turned on in the Pilot app, the video is also stored on the tablet.
This is how you can view video in the User Center.
 
If not a poorly inserted batt, my belief the next likely cause is a bad cell or even a dumb *** smart battery. I say this off my experience with 3 P2's and soon to be P3 pilot. And of course we are going to fly over water, we fly where the beauty is. My favorite is the nudist camp or White House lawn (kidding). All 3 of my P2's have severe crashes due to the failure of the battery as described above. The most recent this week gave me some ideas to research. As before on the previous 2 battery failure crashes, battery was firmly inserted and this time was hovering only a few feet from me for the purpose of running batt down to approx 50-60% since I had not used it on the weekend and may be weeks before using again. All normal until 79% and 11.1v**, suddenly it went to 10%-10.8v, batt icon was empty and flashing, red LEDs flashing and going down fast. Being close I reached to catch and just as quick the voltage shot back over 11v, didn't notice what the percentage was with the chaos, but everything returned to normal seemingly. As I stepped back it immediately went back to before with batt now showing 10.6v and less than 10%, as I caught it I continued to apply power to watch the battery readout. It would alter between a reading of 11.1 or .2 or .3v running strong, to 2-3 seconds later back to 10.4 and falling, with motors going to auto land. Each time the batt icon would show 3/4 full to blinking empty. The back and forth almost seemed like a loose connection with the abruptness of the changes, but now each swap in v readings on the lower end keep getting into the range I thought this thing would not do. It hit 9.8, 9.6, 9.3v and somewhere along here the motors finally shut off. I charged it back up later and after the second flashing light went to solid green, it stopped charging, but pressing the batt button shows a full charge. One of the other failed batt did the same after reaching the third solid green light, can't remember details of the first batt. The Assistant SW showed no indication a problem with the batt, but the cell voltage readings were off a little; 1 3880 2 3815 3 3879. This mean anything? Today I will remove the cells, and try to rebuild using the best cells from my P2 batt infirmary. I'm not sure how to pick the best or identify the bad ones, they all are reading close in volts (smart cap problem?)

With amount of money invested in the pricier drones, in my opinion the battery does not give me the confidence I need my investment will come home tonight (like my ENRON investments). I wonder if a electronic device that can automatically kick in with a batt failure with just enough batt juice to get something like a P2 or 3 say an extra 50-100' for an emergency landing. But thats added weight and cost, plus you add another failure potential. I like the idea though.
**Some values I am not 100% correct, but it definitely got down to the low 9s, thought it shouldn't;t even run that low.


Here's a way to assess the health of a [LiPo] battery:

http://flitetest.com/articles/LiPo_Battery_Internal_Resistance_Testing
 
Thanks for the link, that's my project for today. With 3 organ donors, I may end up with one good one (or may be ordering the P3 sooner than expected) What the heck, my number of crashes is about to exceed my IQ, and I know that can be interpreted either way. But I learn from every mistake, crash and rebuilds, and experiences of others from the forum. Getting all this knowledge may soon bump my IQ up to two digits!
 
Are you aware there are 6 cells inside the battery pack?
It's actually a 2S3P pack.

If your data is correct it looks like cell-2 is the outlier. This makes it a wee bit easier since it will be the center pair.
 
I suspect #2 also, but the smart battery I had taken apart last year after failure, I did not check with Assistant SW to see which cells were suspect. So pulling two good cells from that group might come down to trial and error. I will use jumpers to connect cells to cap to charge and running test with instructions you provided. Originally to test the cells I tried to convince my wife to stick each cell to her tongue like we use to do with 9v batteries, but I think she was wise on that one. Will report on repair hopefully tomorrow. Again thanks for the instructions.captg
 
Well not going as hoped, removed inner two cells, and planned to solder a jumper wire to the metal tabs from the older batt cells to the circuit board in place of the removed cells, but solder will not stick to tabs sticking out of batt. Must be aluminum or something else. Whatever is soldered to the circuit board is then crimped onto the tabs sticking out of the battery. Have to figure a mechanical attachment. I probably will only go far enough to see if feasible, but not to use in actual flight. Was fun up to now.
 
let me add an afterthought . the battery was seated. when I recovered the drone it was hard to pull out. the battery after recovery was dead. Don't know if it died before or after it landed in water. the above picture shows most of the flight was over water. Actually it was mostly over land
LET Me add an update.
DJI has advised me they will do nothing more to assist in the water landing..they sent me a new unit for $800 +. not sure what to do now. water landing occurred when 22% left of battery.
 
Yes and the DJIFlightRecordxxxx].txt has all that data - volts, amps, watts and battery temp (amongst others).
Convert it into a csv http://www.djilogs.com/
Play it in Dashware if you have the profile (not too hard to create if you have the time)
and you may be able to figure out whether battery was at fault or a CSC or other.
So if anyone interested post a log file of the crash (and 1 or two before the crash to compare battery performance) and I or maybe someone else can check -
Her's an example of what the DJI flightrecord can look like in Dashware
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