P3 turned off and fell from the sky

[ParsnipHysorter]

Are you suggesting this is a fact, your theory, or a flaw in the DJI smart battery design?

I must be misunderstanding you, it seems you are asking if it is possible to put a battery that is in auto-discharge mode into a P3? The answer seems obvious, though I wonder why you would question this. If your asking if its a design flaw that it should fly like that -- I would say yes, the P3 firmware should not allow the flight to commence if the battery was recently in auto-discharge mode. However we are really off topic here since the OP says it was recently charged so could not have been in auto-discharge mode.

 

[msinger]

I was told when you conduct a FW update you should leave the update on the SD card and place all of your batteries in the bird so they get updated also with the latest FW

Right -- that only applies to the P3. And, you only need to do it if the firmware includes a battery update. I think DJI recommends always keeping the latest BIN on the memory card since many people are unaware when there is a battery update available.

 

[msinger]

I must be misunderstanding you, it seems you are asking if it is possible to put a battery that is in auto-discharge mode into a P3? The answer seems obvious, though I wonder why you would question this.

You brought it up... and I love to learn new things

The reason I believe this is impossible is because the auto discharge process stops when you press the battery button. And, it certainly needs to be pressed in order to power on the battery.

 

[ParsnipHysorter]

You brought it up... and I love to learn new things

The reason I believe this is impossible is because the auto discharge process stops when you press the battery button. And, it certainly needs to be pressed in order to power on the battery.

Right, that makes sense to me that it could not be in process during the flight. But nothing stops someone from putting an auto-discharging battery into the P3 and going for a flight, along with the possible havoc it caused with battery voltage levels. Actually that makes even more sense when you think it: When a battery is discharging (either during flight or by auto-discharge) the voltage levels are suppressed. Suddenly take away the power load and the voltage will spike for a short period of time -- so you put an auto-discharging battery into the P3, hit that button on the battery, which shuts off the battery discharge load. The P3 turns on, senses a normal voltage, and makes an incorrect assumption about starting power levels based on further assumption that the battery has not been recently discharging... I admit I am making some guesswork of how the P3 firmware logic might process its sensors, but I have some experience with battery behavior in response to loading.

 

[JustinJ]

Right, that makes sense to me that it could not be in process during the flight. But nothing stops someone from putting an auto-discharging battery into the P3 and going for a flight, along with the possible havoc it caused with battery voltage levels. Actually that makes even more sense when you think it: When a battery is discharging (either during flight or by auto-discharge) the voltage levels are suppressed. Suddenly take away the power load and the voltage will spike for a short period of time -- so you put an auto-discharging battery into the P3, hit that button on the battery, which shuts off the battery discharge load. The P3 turns on, senses a normal voltage, and makes an incorrect assumption about starting power levels based on further assumption that the battery has not been recently discharging... I admit I am making some guesswork of how the P3 firmware logic might process its sensors, but I have some experience with battery behavior in response to loading.

The P3 was not "assuming" ANYTHING!?

The battery started @ 58% - it is very SIMPLE to understand..

The load on remaining battery was too much - it was OP error for fly up & away immediately

(They also stated not watching the screen - other than seeing "safe to fly" & did not hover at home point to make quick & simple checks)

 

[msinger]

When a battery is discharging (either during flight or by auto-discharge) the voltage levels are suppressed. Suddenly take away the power load and the voltage will spike for a short period of time -- so you put an auto-discharging battery into the P3, hit that button on the battery, which shuts off the battery discharge load. The P3 turns on, senses a normal voltage, and makes an incorrect assumption about starting power levels based on further assumption that the battery has not been recently discharging

It's an interesting theory for sure. However, when I smell pilot error, I like to rule out all logical possibilities first.

 

[ParsnipHysorter]

The P3 was not "assuming" ANYTHING!?

The battery started @ 58% - it is very SIMPLE to understand..

The load on remaining battery was too much - it was OP error for fly up & away immediately

(They also stated not watching the screen - other than seeing "safe to fly" & did not hover at home point to make quick & simple checks)

I know these threads can be hard to follow, but I was not saying in this particular case the P3 assumed anything. I was talking about auto-discharge in general, which appears to not be a factor in this instance because the OP had charged the battery just the day before.

However, the OP says it reported 98% prior to the flight. The flight log says it started at 58%. But the flight log begins at takeoff while it seems he looked at the screen before takeoff. Did he misread it ? Maybe. But if dropped out of the air after a 30% drop immediately after takeoff there must be a fault somewhere, probably in the battery. And even if the OP flew away at 58% I wouldn't call it OP error necessarily; these do not automatically drop out of the air if you take off at 58% -- shoot I've done that many times and had no problems, though I generally try to make sure I fly with a full battery.

 

[msinger]

And even if the OP flew away at 58% I wouldn't call it OP error necessarily; these do not automatically drop out of the air if you take off at 58%

Agreed -- else we'd see this same post numerous times per day here. The OP didn't just casually fly away though. Check out the log if you'd like to see exactly what happened.

 

[TheRealNick]

The .dat file starts as soon as power-up, so from that you could plot the voltage until takeoff.

Jake,

When you play back the flight in the DJI go app what battery levels does it show? That log also starts before takeoff.

Voltage is not an accurate way to determine SOC....and it is also all that is available when you start. It can be accurate at full charge. I always check that battery voltage is at >17V before flight....anything less and I would definitely not fly....

 

[JustinJ]

I know these threads can be hard to follow, but I was not saying in this particular case the P3 assumed anything. I was talking about auto-discharge in general, which appears to not be a factor in this instance because the OP had charged the battery just the day before.

However, the OP says it reported 98% prior to the flight. The flight log says it started at 58%. But the flight log begins at takeoff while it seems he looked at the screen before takeoff. Did he misread it ? Maybe. But if dropped out of the air after a 30% drop immediately after takeoff there must be a fault somewhere, probably in the battery. And even if the OP flew away at 58% I wouldn't call it OP error necessarily; these do not automatically drop out of the air if you take off at 58% -- shoot I've done that many times and had no problems, though I generally try to make sure I fly with a full battery.

Maybe hard for you to follow but I'm doing ok thank you for your concern.

I still believe OP error.. the evidence so far suggests this (whereas the theory does not disprove anything)

 

[ParsnipHysorter]

Maybe hard for you to follow but I'm doing ok thank you for your concern.

I still believe OP error.. the evidence so far suggests this (whereas the theory does not disprove anything)

No need to thank me. Some people struggle with poor reading comprehension combined with short attention spans which makes it difficult to see past the prior post on these forums. They readily take things out of context when they post. I don't know if this is the fault of the individuals or the educational system today but it is just something we need to recognize and deal with.

 

[msinger]

NSome people struggle with poor reading comprehension combined with short attention spans which makes it difficult to see past the prior post on these forums. They readily take things out of context when they post. I don't know if this is the fault of the individuals or the educational system today but it is just something we need to recognize and deal with.

Welcome to the Internets.

 

[Luap]

This is typical crash when flying with batteries that have not been fully charged.
At least since roughly two months - never read of any of these posts / logs before that - so probably from an update DJI did.

 

[Scottb527]

The Phantom does have a built-in fail safe that is supposed to auto land the Phantom at its current location when it detects the battery is critically low. It seems there are some scenarios where that fail safe is not activated though. A rapid steep climb on a low battery is one of those scenarios that has popped up a lot lately.

Where are you getting your information from? You are an approved vendor, but is that an official response from DJI? That would be ridiculous for a rapid climb to suddenly drop a battery so low that it shuts off. The technology in these machines is amazing. To not be able to climb out at full throttle with even a 40% battery would have these things falling out of the sky steadily. Please verify if this statement you've made is an official statement from DJI?

 

[msinger]

Where are you getting your information from?

Endless hours of research.

You are an approved vendor, but is that an official response from DJI?

All comments and/or opinions are my own. I do not work for DJI, nor do I represent them in any way.

That would be ridiculous for a rapid climb to suddenly drop a battery so low that it shuts off.

The battery was nearly half depleted at the time. And, it was about 28% away from the level when most people are (or should be) considering landing (~30%). This is of course what the logs are telling me. I don't know what really happened since I was not there.

The next time you take off (on a full battery), gun the throttle really hard and ascend straight up. Watch what happens to the battery voltage. It'll dip and then come back up when you let off the throttle. Now, imagine that dip when the battery has half that charge and you put the same amount of stress on it. It's pretty easy to see how you could reach the 3.0V danger zone.

Please verify if this statement you've made is an official statement from DJI?

Nope. I don't speak for DJI. I do however use logic and reason to put two and two together.

 

[Scottb527]

Thank you for your replies.

 

[Tony Wilson]

I read somewhere when you conduct a FW update before removing the micro card you should place every battery in the craft and turn them on for a up-date. This crash came on the second battery. Was the second battery updated before the flight ?

 

[alokbhargava]

I read somewhere when you conduct a FW update before removing the micro card you should place every battery in the craft and turn them on for a up-date. This crash came on the second battery. Was the second battery updated before the flight ?

If the battery was not updated previously, it will get updated when you switch it on aircraft and the SD card had the bin file.

 

[1st_time_flyer]

Endless hours of research.


All comments and/or opinions are my own. I do not work for DJI, nor do I represent them in any way.


The battery was nearly half depleted at the time. And, it was about 28% away from the level when most people are (or should be) considering landing (~30%). This is of course what the logs are telling me. I don't know what really happened since I was not there.

The next time you take off (on a full battery), gun the throttle really hard and ascend straight up. Watch what happens to the battery voltage. It'll dip and then come back up when you let off the throttle. Now, imagine that dip when the battery has half that charge and you put the same amount of stress on it. It's pretty easy to see how you could reach the 3.0V danger zone.


Nope. I don't speak for DJI. I do however use logic and reason to put two and two together.

Now I'm totally confused, you mean to tell me that if I stick a battery in my P3 that is at say 50% charged and I fly it aggressively causing the battery to go into what you call the 3.0V "danger zone" that it's MY fault??!!? I am not the OP of this thread but I find It very hard to believe that I can't fly my quadcopter with a 50% charge aggressively without it falling out of the sky........

 

[Lonewolf]

Now I'm totally confused, you mean to tell me that if I stick a battery in my P3 that is at say 50% charged and I fly it aggressively causing the battery to go into what you call the 3.0V "danger zone" that it's MY fault??!!? I am not the OP of this thread but I find It very hard to believe that I can't fly my quadcopter with a 50% charge aggressively without it falling out of the sky........

Believe it. Because, I did it. Just to see how long I could fly with a battery that was 53% charged. Fired up my P3 lead it at a low hover & flew it slowly around at that hover level of 3ft. Flight lasted less than 2 minutes & it went into auto land.