P3A fell out of sky... can someone look at data and explain???

[flyNfrank]

I guess that means that not everyone on the internet has read your posts.

There's too much victim blaming on this board. How would a new DJI customer know that their batteries need to be fully charged? Is there some kind of warning before you buy one? Is it on the box? No, well then DJI should replace it, fully charged before flight or not.

I've also never seen anything but anecdotal evidence that this is true. I know frank will come say, "Every time I see a post about a bird falling from the sky, they took off with less than 100% battery." Well, duh, most people take off and land multiple times per session. Odds are that most failures will hit people who have taken off with less than 100%.

It's not my post that someone needs to be concerned with reading. The manual clearly states to never fly without a fully charge battery. Had you read the manual yourself you would know this.

 

[GimbleOut]

May I ask out of curiosity as to why you shouldn't fly your phantom with a battery that isn't 100%...

That's like saying guys don't use your tablet unless it's 100% it might just die randomly because well you didn't charge it?

Makes no sense. 100% or 50% the volts should be consistent?


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That's the issue exactly. As load increases volts drop. With a battery that isn't fully charged the takeoff energy capacity is an estimate. The longer the battery sits the more uncertainty in the actual energy available. Only under load will the actual energy available be known to the system. If your up and it ain't enough....problems.



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[Rommel]

Very interested in this thread. I've only had my phantom 2 months so I've never had a battery sit more than 3 or 4 days. But I do take it down to 30 percent sometimes and often do a few short fights on one change.
Not arguing with or questioning anyone here, but it seems absurd that I shouldn't be able to safely fly my drone at 50% charge.
There's got to be more to this and I wonder if thing are exaggerated since people mostly come to forums to report a problem. Dozens of people saying "done fell from sky". But you never read about the countless fights with a battery below 50% cuz nothing went wrong.

Tony

 

[Rynocity]

That's the issue exactly. As load increases volts drop. With a battery that isn't fully charged the takeoff energy capacity is an estimate. The longer the battery sits the more uncertainty in the actual energy available. Only under load will the actual energy available be known to the system. If your up and it ain't enough....problems.



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You have any source to back this up or is it a wag?

 

[Rynocity]

It's not my post that someone needs to be concerned with reading. The manual clearly states to never fly without a fully charge battery. Had you read the manual yourself you would know this.

The manual says to always update to the newest firmware before flight, do you do that?

 

[msinger]

Just lost pro 3 in the ocean.

That's quite the special case. The OP admitted he never updated the firmware (he could have been using 1.5) and DJI replaced his Phantom for free.

 

[Mocho]

IMHO the only logical reason DJI put's such nonsense in their manual is that their smart system is not really that smart and they don't trust it.
So to compensate they ask the user's to fly with 100% battery.

Because it say's so in the manual, is NOT a good enough answer. It needs to be backed up with reason, else it's just fluff and a reason to blame pilots for crashes.

I've used LiPo's for my R/C hobbies for a lot of years and have never heard such nonsense, as far as the battery itself is concerned.

 

[D'sAdvanced]

No and more no.

The battery capacity value that DJI puts up on the screen is very approximate and typically spurious. It is calculated using several ASSumptions that often do not hold up.

Furthermore, if the battery has sat unattended, uncharged and unloved for several days, it is anything but clear that the numbers displayed on the app mean much of anything. Supposedly they have fixed this after the 1.6 upgrade but many of us wonder. The OP really had no idea what his battery status actually was when the thing crashed. The logs will help.

Always turn on 'Show voltage on screen' from the app and look at it carefully. Land early, land often.

I usually keep fully charged batteries 3-4 days prior to flying. The battery I flew yesterday sat fully charged for 8 days and flew perfectly. Landed twice and took off 3 times all on same battery - no issues whatsoever.

 

[kirk2579]

Very interested in this thread. I've only had my phantom 2 months so I've never had a battery sit more than 3 or 4 days. But I do take it down to 30 percent sometimes and often do a few short fights on one change.
Not arguing with or questioning anyone here, but it seems absurd that I shouldn't be able to safely fly my drone at 50% charge.
There's got to be more to this and I wonder if thing are exaggerated since people mostly come to forums to report a problem. Dozens of people saying "done fell from sky". But you never read about the countless fights with a battery below 50% cuz nothing went wrong.

Tony

I think the issue about battery charge and flying is when the FIRST flight of the day is started with a less than fully charged battery.

If one is flying and simply lands , for short time and re takes off the issue is not so much..

The reason is the first case (battery sitting and maybe into self discharge mode) the actual charge level is a GUESS.
the second case the charge has been calculated and known by the system is much more accurate.

good luck and have fun flying!

 

[kirk2579]

You have any source to back this up or is it a wag?

No its not "wag"

its history and been there done that for the most part.

go back about 6 -9 months back and google the forums about battery and phantom, much discussed and all these questions have been gone over and over.

good luck and have fun flying!

 

[impilot51]

Every flight is not the same, and anecdotal evidence of someone flying in a manner that they should not is not proof that one should not do that. Flying cold with a partially charged battery may not have the capacity or deal with a high load situation (full owner take off, for instance). At least that's what I seem to have gleaned from all the posts. Before anyone bashes me, I don't know this to be true, just a condensed version of what I have read.

So, I choose to believe the manufacturer when they say to start with a fully charged battery. Cheap insurance and a little piece of mind. Of course many will choose to do their own thing, and then wail that it should not be that way. To each their own.


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[t2adze]

I have question to people who claim it is a problem that OP took off with 75% battery.
With that logic, you are saying that: If you fly one place, your battery goes downs to around 70%. And then you have to drive somewhere else and fly there - that can't happen without your bird dropping out of the sky?
Doesn't make sense for an "expensive toy".

 

[impilot51]

I'm not saying it will happen every time. Of course not. But based on enough threads here discussing the topics and phantoms dropping due to low voltage (that did not start out with a full charge), and the manufacturer very clearly stating in their battery documentation the following:

Then I guess I choose not to tempt the battery gods. I will do a touch and go at the same location, but only after the batteries are well warmed up (at least 25% discharged), and on the ground for no more than may be 1 minute max. But if I shut down and move to a new location, that battery is done for the day.

 

[msinger]

But based on enough threads here discussing the topics and phantoms dropping due to low voltage (that did not start out with a full charge)

I've only seen Phantoms running firmware 1.5 drop on their own. Assuming people are running the latest firmware, there should be nothing to worry about. The fail safe features should make the Phantom land before the battery shuts off. That could mean a crash landing too if the pilot is not aware of how those fail safe features work.

 

[impilot51]

Not willing to take that chance...to each their own. Especially when the solution is trivial.

 

[HWCM]

No. He's saying you never should have launched in the first place. You should not launch with your battery at 75%. That was your first mistake.

Your second mistake was launching yet again on the same battery.

Both launches were fatal errors. You got lucky on the first flight. Fate prevailed on the second flight.

Next time, be sure to have a fully charged battery. If you want to make multiple flights, carry multiple fully charged batteries with you.

Sorry for your loss.

I don't, it's not my post. I was making a point.

Before you go too far in to retrieving logs, I assume that you checked to make sure all the props, or at least the prop hubs were still attached when you retrieved the aircraft? If not, then you know what happened.

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[HWCM]

Here is what happens and to help clear this up.
It's called voltage sag.
So he took off with 32% battery on a cold battery. 32% was correct, the phantoms flight controller is basically a computer and can do simple voltage readings.
Now, he flew around and out 150 feet waiting on the failsafe, to show his buddy. Maybe he full throttled it a few times and that pulls a lot of current, this is where voltage sag comes in. Those quick fast full throttle bursts cause the battery to immediately dip, sometimes drastically. His battery dipped below the required current/voltage to run all four motors and keep the quad in the air. So they cut out and drastically slowed down...no motors spinning fast = no lift = crash.
Now, on the ground, with no load the battery will bounce back to say...20+%. Then you are confused as to why it crashed with 20% battery left and the failsafe did not kick in.
You can test this with a lipo alarm or lipo meter with digital display.
You can plug the lipo meter into a lipo battery (one with a balance plug), start the motors and read the voltage 12.97 volts, hold the quad down and full throttle (load) you can watch the lipo meter voltage start to drop instantly, if it's a low "C" battery, it could dip as low as 10v.
So if you start with 11v and full throttle it or fast maneuver it = voltage sag= not enough power to run four motors and props = gravity = crash.
Okay, we are done here.

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[msinger]

HWCM, that story would be very believable if the OP was running firmware 1.5. We still have no idea what happened since he is MIA.

 

[flyNfrank]

The manual says to always update to the newest firmware before flight, do you do that?

Are you aware this is a Phantom 3 forum? If you are,...then you have really shown your ignorance in the quoted post above.

Also as you may know it's just not good to use multiple accounts to disagree and argue with members. Basically if you don't have any intention on contributing some positive things to the community, then there's really not much reason for you to stick around, is there?

 

[fastfed]

Sorry about your accident, but yet again the dreaded "fell out of the sky" and all because you didn't have your battery fully charged before flying, NEVER fly your phantom with a partially charged battery, always fly with a fully charged battery, there are countless threads about this

well regardless, they need to fix that issue then, whether its a reading issue that the readings are off or a major defect in the battery.
I've had too many RC's and many other things under battery power and I've never seen it go from 30% to 0% in the matter of a second. Something is wrong