WTH Just Happened? Props just flew off!

yorlik said:
burlbark said:
I just had a customer contact me from Florida. Same exact thing just happened to him with his 5 week old Version 3. Was flying at 60ft elevation and all 4 motors shut down while he was flying forward. It came crashing to the ground totaling it. I have referred him to DJI, if they dont know whats going on they wont fix it. It has to hit them in the pocket book for them to change it.

Jeremy

EXACTLY same scenario for our #2 unit, 4 wk old. sent back to ca dji with paperework filled out requesting warranty rpr due to bad battery. time will tell...

So in this brief period of time we have 3 reports of Version 3's shutting down midflite with no apparent reason... As least with motor lead failures we could see what was happening. This leaves us to ponder all sort of explanations and no concrete evidence at this time.... :?:

Jeremy James
 
burlbark said:
jshull0 said:
IflyinWY said:
Did you use the wrench and torque your props?

I never use the wrench, but for some reason with the new v3.0 motors the wrench doesn't seem to work well anyways. I always spin tighten and make sure the blades spin on nice and tight. Never had a problem prior, but it makes me rethink.

Post a pic up of the gimbal if you can.... It may be repairable. As long as the crash didnt jam the j-arm into the main board it can be fixed. I have only had 2 sent into me that crashes had completely wiped out and they where not repairable.

Jeremy

I would send you mine but hoping the the repair will be covered under the waranty...

viewtopic.php?f=27&t=36623
 
our esc all 2.1, yellow marker on cap. motor leads fine. IIRC they also had the dji solid wire fix (silicone glue around them to prevent the vibration broken wire issue (ie, no need to replace motor leads with hi flex cable). ours was definite battery issue. fully charged, right off charger, brand new battery, yet it shut off in air after 2 minutes, and fell. this would not happen to me flying my #1 unit, as i will have flite log showing all variables and screen recording. unfortunately the others who fly #2 unit at our place are no where near as thorough, hence the questions afterward.
 
burlbark said:
I just had a customer contact me from Florida. Same exact thing just happened to him with his 5 week old Version 3. Was flying at 60ft elevation and all 4 motors shut down while he was flying forward. It came crashing to the ground totaling it. I have referred him to DJI, if they dont know whats going on they wont fix it. It has to hit them in the pocket book for them to change it.

Jeremy

Dang, I've been busy with work the past few days and have started to rebuild the phantom and saw this. I'm curious as to what dji is going to say about the matter. Don't want to rebuild and have the same thing happen again. :shock:
 
IflyinWY said:
So, we're still wondering WTH really happened, aren't we?

I would like to know more about your battery.
What is the discharge rate?
What does DJI say about battery performance at high altitudes? :lol: Yea, I know that was funny.

If I read your posts correctly, you took off from 11,000 feet above sea level, with the ambient air temp between 30 and 40 degrees Fahrenheit, & went straight up quite a ways, then went hauling butt for a quarter mile with a top speed of 38 mph and hit reverse,
so to speak.

I don't think this really is a factor, but it may be.
Can you guess what the temperature of the battery was when you started the motors?

Did it spend the night in the trunk of the car?


I'm leaning more and more towards "sucking the power faster than the battery can supply".

When I do that to my dumb batteries, they just make the bird want to land.
I wonder what happens to those smart batteries when they drain too fast.

I think we may have just found out.

Let's see, the batteries were stored in the house and fully charged the night before flight. I had the heat on with everything riding in the back seat. Batteries couldn't be too cold maybe 60 - 70 degrees. I didn't have any heater vents blowing directly on bird or batteries. Before flight I did compass cal, and made sure to manually lock home point, Started vision+ utility, and started logger. Logger is stored locally in phantom and has to be downloaded from phantom at end of flight.

Battery was off when I found the bird, however battery showed a charge. I sure as heck didn't turn the battery off when phantom was 600 ft up. Did battery turn it's self off due to some internal safety feature? The batteries basically went from 60-70 degrees F to being left in 38 degrees for about 4 - 5 min before motor startup. I don't think I mentioned it before, but I'm running 3.08.
 
djsydvicious said:
I would send you mine but hoping the the repair will be covered under the waranty...

viewtopic.php?f=27&t=36623

Wow sounds too familiar to be a coincidence. Now I'm starting to think that it doesn't matter how much money I throw at this thing in parts if I'm doomed to repeat. Being worried while flying takes the fun right out of it.
 
I'm thinking of doing a load test on the battery, does anyone know what the maximum current draw of the phantom 2 vision + is, more specifically a v3.0? I want to measure voltage drop and see if I can trigger a safety shutoff.
 
Thanks for the reply jshull0,

So now we know the battery wasn't too cold to function properly.
I would imagine your smart batteries keep themselves warm, as my battery does, as it discharges.

I hope you can perform a good load test. That will be good data.
I'm surprised the discharge rate isn't commonly known.
 
IflyinWY said:
I'm surprised the discharge rate isn't commonly known.

It is recorded once per second in Ken's ultimate flight log. Example attached. It is the currentCurrent column and is in milliamps for our 5 amp-hr rated batteries.....

1-2 amps props idling on ground before take off
14-18 amps holding altitude against small sind gusts
20-30 amps rising depending on speed
 
Great discharge info for the Phantom.

My bad, I should have specified the rated "Battery Discharge".
 
IflyinWY said:
I should have specified the rated "Battery Discharge".

What does that mean?

It is a 5000mah battery. Means it can put out 5000ma, or 5 amps, for 1 hour.
 
burlbark said:
So in this brief period of time we have 3 reports of Version 3's shutting down midflite with no apparent reason... As least with motor lead failures we could see what was happening. This leaves us to ponder all sort of explanations and no concrete evidence at this time.... :?:
Jeremy James

A friend experience something very similar to what is being discussed here. A few weeks ago his P2V+ ver 3 suddenly fell out of the sky.

At the beginning of his flight he did the typical left-right, forward-back, up-down maneuvers to test the quad before setting off. All was well.
Then, as it was flying slowly forward, the bird suddenly tilted and fell straight to the earth, severely bending the gimbal. One of the props was totally missing and was later found undamaged about 60' from the crash site.

Later, we tested the motors and all except for the poor gimbal seemed functional. All four motors sounded normal and felt normal when spun by hand. We then opened the shell for the first time to look for any signs of ESC trauma. All looked well on and around the v2.1 ESCs.

The craft is currently moldering on a pallet somewhere in a DJI repair queue. My friend is hoping for a warranty repair but without any video of the malfunction he may end up paying for a new gimbal ($$$$$).
 
yorlik said:
IflyinWY said:
I should have specified the rated "Battery Discharge".

What does that mean?

It is a 5000mah battery. Means it can put out 5000ma, or 5 amps, for 1 hour.


Well, I understand the "C rating" of a LIPO battery to mean:
the rate at which the battery can be safely discharged without damaging the battery.

The batteries I use have 3 important bits of information on the label:
1) mAh or milliamp hours
2) S or how many cells are connected in series
3) C which is preceded by a number like 10, 20, 30 and so on; otherwise known as "the continuous discharge rate"

Some batteries also include the "maximum burst C rating" which will be higher than the "C" number, and indicates how rapidly you can discharge the battery for a few seconds.

The stock Phantom FC40 battery is a: 2200 mAh, 20C, 3S
My battery doesn't say it's a 3S but it came with the bird and has 3 cell leads coming out of it, so I know it's a 3S.

EDIT:
I almost forgot the most important part.
My stock battery can discharge at a maximum sustained load up to 44,000 milliamps or 44 amps.

It seems the only common information about your smart batteries is the mAh.

EDIT #2:
There's a lot of good info here:
http://www.rchelicopterfun.com/rc-lipo-batteries.html
 
Yep, there is lots of interesting details on batteries!

Charles Coulomb came up with the famous C rating back in the 1780's. It used to be used for 1 or less, until more recently when folks began adding the >1 number in front of it to show max charge and discharge capabilities. Interesting article at Battery University on it: http://batteryuniversity.com/learn/arti ... the_c_rate

The phantom vision+ v3 is a 3 cell lipo (easy to guess that 'S' number since rated voltage/3-4vpercell tells that) is rated 5ah. Your phantom FC40 only has a 2.2ah battery? Seems like that would mean your flight time is 1/2 the pv+?

Also interesting that your battery has so many leads coming out of it! mine has just 2 power leads - they handle equalizing the charge among the 3 cells electronically inside.

Based on the csv files I have seen for my pv+, the MAX current draw is limited to 32.6 amps peak....
 
Wow lots of good info being exchanged, I would post up some pictures of esc, motors, wires, but site keeps giving me issue as far as posting pictures is concerned.
Ah, there we go. Well all the connections look solid except this one on the main board to the esc. The wires were pinched upon impact from esc to motor, and one of the FET's on that esc defiantly got hot. In fact that same FET on all 4 esc looks like they got hot.



 
yorlik said:
Yep, there is lots of interesting details on batteries!

The phantom vision+ v3 is a 3 cell lipo (easy to guess that 'S' number since rated voltage/3-4vpercell tells that) is rated 5ah. Your phantom FC40 only has a 2.2ah battery? Seems like that would mean your flight time is 1/2 the pv+?

Also interesting that your battery has so many leads coming out of it! mine has just 2 power leads - they handle equalizing the charge among the 3 cells electronically inside.


Yep, about half the flight time you get.
We get 10 to 15 minutes of flight time, according to DJI. http://www.dji.com/product/phantom
The P2V+ gets 25 minutes of flight time, again according to DJI. http://www.dji.com/product/phantom-2-vi ... us/feature

So now we know one of the added features of your "Smart" battery, over mine. Yours doesn't need each cell directly connected to a charger which does the thinking for it.


jshullO, am I looking at copper in the red wire? Are there any signs of arcing?

How can we find out if your FETs got hot prior to or as a result of impact?
 
jshull0 said:
Wow lots of good info being exchanged, I would post up some pictures of esc, motors, wires, but site keeps giving me issue as far as posting pictures is concerned.
Ah, there we go. Well all the connections look solid except this one on the main board to the esc. The wires were pinched upon impact from esc to motor, and one of the FET's on that esc defiantly got hot. In fact that same FET on all 4 esc looks like they got hot.




That sure was a cold solder joint. I would expect the copper to tear off the mainboard before the solder let go. That could have been your failure.

Jeremy
 
All the wires were pinched against the esc when the arm bent. All the damage to wires were caused by crash. There's no visible sign of arching on wires or esc.
 
burlbark said:
jshull0 said:
Wow lots of good info being exchanged, I would post up some pictures of esc, motors, wires, but site keeps giving me issue as far as posting pictures is concerned.
Ah, there we go. Well all the connections look solid except this one on the main board to the esc. The wires were pinched upon impact from esc to motor, and one of the FET's on that esc defiantly got hot. In fact that same FET on all 4 esc looks like they got hot.




That sure was a cold solder joint. I would expect the copper to tear off the mainboard before the solder let go. That could have been your failure.

Jeremy

That's what I was thinking too, is it that imperative to keep heat off the main board or esc while soldering? I ask because I was debating on using a fine silver solder that requires a little bit more heat to melt, but is better at handeling current. I have a adjustable iron with a very very fine point, just wondering.
 

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