P3P - Loss of Power and Crash

[EVDrones]

Good morning.

Last Wednesday I took my P3P out for a quick flight to get a couple of pictures. The flight was quicker that I though. 10 seconds on the ground and 3 seconds in the air, straight up and the power shut off and the bird fell to the asphalt parking lot.

Gimble is toast. Legs are bent and the housing has some issues.

Contacted my retailer for the bird and opened a DJI support ticket because the battery was purchased directly from DJI.

I was able to power up the bird with a different battery and download all the flight logs. I have also saved the logs from the iPhone 6.

A little background. Last Sunday I upgraded the DJI Go App to the latest version, upgraded firmware on the receiver and phantom to the latest and made sure all four batteries where cycled through the phantom and fully charged.

Took 4 flights on Monday without issues Three on one battery and the last of those flights with the battery used on Wednesday and just the one quick flight on Wednesday.

So a fully charged battery with a 5 minute flight and then two days later a 3 second light at 54%

I will post some pictures and a video of the flight log shortly.

Any recommendations on how to navigate the the RMA maze?

 

[Zach2.0]

Good morning.

Last Wednesday I took my P3P out for a quick flight to get a couple of pictures. The flight was quicker that I though. 10 seconds on the ground and 3 seconds in the air, straight up and the power shut off and the bird fell to the asphalt parking lot.

Gimble is toast. Legs are bent and the housing has some issues.

Contacted my retailer for the bird and opened a DJI support ticket because the battery was purchased directly from DJI.

I was able to power up the bird with a different battery and download all the flight logs. I have also saved the logs from the iPhone 6.

A little background. Last Sunday I upgraded the DJI Go App to the latest version, upgraded firmware on the receiver and phantom to the latest and made sure all four batteries where cycled through the phantom.

Took 4 flights on Monday without issues One of those flight with the battery used on Wednesday and just the one quick flight on Wednesday.

I will post some pictures and a video of the flight log shortly.

Any recommendations on how to navigate the the RMA maze?

Wow that sucks I haven't had any problems like that with p2v+.

 

[EVDrones]

Flight Log video.

Notice that the only stick movement is during the liftoff. No other input. Maximum altitude was 41' straight up (with a little horizontal wind drift movement).

 

[Zach2.0]

Flight Log video.

Notice that the only stick movement is during the liftoff. Maximum altitude was 41' straight up (with a little horizontal movement).

Thats weird. I have never seen that before,also is your p3 ok?

 

[rmfa]

Did you start with a fully charged battery?

 

[bluer101]

Looks like you flew on a previous used battery. I see no flight time on the meter. From some other people reporting and seeing you gun the throttle to 100% up the P3 sucked too much juice and with partial battery shut off. This is just my opinion, have not been flying long.

 

[EVDrones]

 

[Zach2.0]

Contact DJI support for help or someone that does repairs

 

[EVDrones]

Here is the Healthdrones.com report

HealthyDrones.com - Innovative flight data analysis that matters

And yes the battery was not at full charge but it had a full charge on Sunday, one 5 minute flight on Monday and was only going to be used for a less than one minute flight for a single picture on Wednesday. The battery showed 54% at the beginning of the flight and also at the end of the 14 seconds. (10 seconds on the ground with the props spinning and 3.x seconds of flight.)

Rotating the healthdrones view shows that the area was asphalt and clear of the trees.

Went straight up, motors quit and fell.

I know everyone says you need a full charge but at 54% it should have had enough power to at least land on its own and not just shutoff by itself. If that is the case DJI has some major liability on their hand when birds start crashing into people.

 

[Luap]

Here is the log from the dat:

You will note that battery capacity indicates 54% at end of flight (red bar on chart) but voltage per cell is between 2.84 and 2.93v. A lipo indicating such low voltage means battery is empty - so again this is an error/bug in the smart battery thinking it has 54% remaining capacity when it should be 0%.

Here same pattern Phantom 3 fell from the sky today (lost power?) | Page 3 | DJI Phantom Forum
I wonder when DJI will come with a fix for this.

 

[Timelinex]

I feel for you. It is most likely because of the battery not being charged recently. There have been multiple threads with the same thing happening. The battery indicator is wrong. It's an inherent flaw in the way battery remaining is measured.

Unfortunately you won't get much sympathy on this forum, because everyone on here believes you should be born with the knowledge of not flying on a battery you didn't charge in the last 2 days (even though it says you have battery left). In their eyes it's your fault. You should have know better, don't you always throw out your calculator batteries when you haven't used them in a few days? (/end sarcasm).

The reality is there is no excuse for this to happen. If it's known by insiders that battery capacity is inaccurate when not charged in the last X days, then the 'smart' batteries should not allow you to use them. The same way they know to drain themselves in X amount of days.

 

[bobmyers]

Here is the log from the dat:
View attachment 37624
You will note that battery capacity indicates 54% at end of flight (red bar on chart) but voltage per cell is between 2.84 and 2.93v. A lipo indicating such low voltage means battery is empty - so again this is an error/bug in the smart battery thinking it has 54% remaining capacity when it should be 0%.

Here same pattern Phantom 3 fell from the sky today (lost power?) | Page 3 | DJI Phantom Forum
I wonder when DJI will come with a fix for this.

DJI recommends flying with a fully charged battery. There is a reason for that recommendation and this is the reason. The P3 may crash with a partially charged battery. The readouts are apparently not accurate unless the battery starts at 100% fully charged.
Sorry about the loss.

 

[Scozz76]

I did a drain test on one of my batteries and found the pack will turn off at 12.2v (3.05v/cell).
Under no load the batteries voltage is going to be higher than it's actual voltage. Maybe it'll pay to hover a few feet for a short time and let the battery/meter stabilise.

 

[bobmyers]

I did a drain test on one of my batteries and found the pack will turn off at 12.2v (3.05v/cell).
Under no load the batteries voltage is going to be higher than it's actual voltage. Maybe it'll pay to hover a few feet for a short time and let the battery/meter stabilise.

Probably be better to recharge to 100%. Draining a lithium ion or lithium polimar battery that low, will not help the life of the battery and you could well brick it doing that kind of testing. Tester beware.

 

[MattyDread]

It shows your battery cells 3.3 or below = toast. Best to check the voltage levels & not battery %

The moral of the story - always fly with fully charged batteries

 

[Scozz76]

Probably be better to recharge to 100%. Draining a lithium ion or lithium polimar battery that low, will not help the life of the battery and you could well brick it doing that kind of testing. Tester beware.

I'm well aware of how these batteries work and was ready to pull the testing at 12v (3v/cell).
I'm suggesting that maybe the meter needs time to respond accordingly to the voltages.

 

[bobmyers]

I'm well aware of how these batteries work and was ready to pull the testing at 12v (3v/cell).
I'm suggesting that maybe the meter needs time to respond accordingly to the voltages.

The meter is based on starting with the battery at 100% charge. That is what it calibrates from.

 

[Scozz76]

The meter is based on starting with the battery at 100% charge. That is what it calibrates from.

Well then, there is really no point to this meter and you'd be better off modding the batteries to include a voltage monitor/alarm.

 

[TheRealNick]

So sorry for you crash. Looking at the flight data I can add some possible insight/help/explanation.

When he powered on the voltage was at 15.1 V or 3.76V. At this point this is the only information the Phantom has to determine the SOC for the battery. From my experience flying from a full pack that is about where the Phantom estimates the remaining charge to be around the 54%. As he took off the voltage dropped rapidly. It was below 14V at about 3 second and I figure he had maybe 1 second to notice and land (see chart below). As Luop mentioned I not sure why the SOC of the of battery didn't change, unless is sets based on the starting voltage and then uses current integration from there or is not re-calculated frequently....

I just looked at another DAT file and noticed capacity did not change for about 8 seconds....so perhaps it does not update that often, what do you think @BudWalker, how often does remaining capacity update?

The amount of energy taken from the battery before crash was very low by my calculations, like less than 1 Wh (the battery is 68 Wh).

It does not appear the initial assessment of the battery's SOC was off based on the voltage, but it seems that the Phantom did not determine soon enough that the SOC was not accurate....

 

[alokbhargava]

Well then, there is really no point to this meter and you'd be better off modding the batteries to include a voltage monitor/alarm.

We can't use a voltage monitor for such batteries as the voltage characterizes are very flat and suddenly droop after a knee value. One has to work out a charge curve to estimate the remaining juice at any time.