It was second fly today and there was about 40-50% battery charge, when I got a message "Critically Low Battery Voltage", "Landing Now", "Disconnected" all during 1-2 seconds. Power disconnected, motors stoped, aircraft fall down from 100m altitude and crashed. Completly broken.   What is the problem?
   Everything was Ok, IMU - Ok, Compass - Ok, Safe To Fly Mode (green button on screen). Firmware/Software up to date.

   Last recorded file damaged and cann't open with my desctop. Anyone have an idea how to recover unfinished MOV?

Did you start the flight with a full charge?  You need to stick sd card back in a phantom p3 and turn it on.  That should fix it for you.  Your device might have the cached version for you if you had video caching turned on.

I recommend to full charge before flight.. dont dare to 40-50% to fly 100m high, 30% balance start 1st warning, and another 20% make final warning critical low battery warning.. that time you still 100 m high, no power to return back, i guess..

It was 100% charged today. I made one fly about 10 min, stop device, power off, go to another place and start the second fly with 65% charged battery at the start.
Do not confuse "Low Battery Warning" with "Critically Low Voltage Battery". It was first time i saw this msg.
And another thing - I have no time to do something 1. Safe to fly, 2. Msg "Critically Low", 3. Disconnect aircraft - all within 1 or 2 seconds!
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I'm carefull to turn it on before DJI Support give me answer.
I can recover file with recover_mp4_to_h264.exe

You need to open a ticket with DJI and send it in.  Possible battery not in properly or failure.  Starting from 65% is not recommended but I have done it my self.  That should broke try of power but to be 100% clear DJI only recommend flying a fully charged pac, I would not start a flight much below that though unless just hovering.

clear 100% is not every time right after charge, 98%, 96% - is it safe to fly with 95%?, or 90% after colibration and IMU check - what is the safe power charge? =)))))
I think 30% - warning and 10% Critical Level as default settings are. And "Safe To Fly" means - Safe to fly.
I sent a message via Contact Support Page - is it correct? Or what is the ticket you mean?

grigorriy Posted at 2015-10-8 03:16
clear 100% is not every time right after charge, 98%, 96% - is it safe to fly with 95%?, or 90% afte ...

I'm with you on this point.  If the app says "Safe to fly", then... it should be safe to fly.

Mad_Angler1 Posted at 2015-10-8 05:04
You need to open a ticket with DJI and send it in.  Possible battery not in properly or failure.  St ...

I've done the same thing, a few times with no problems.
Can anyone explain why it's not ok to fly.., then land.., then fly again?

What's the difference between flying in the air with a 100% battery.., which will eventually drop to 60% and still fly all the way to 30%.

As opposed to flying in the air with a 100% battery.., which eventually drops to 60%. Then turn off motors and land for 10mins.., and fly again.

How does the 10min rest affect the batteries? Should this be made clear in the safety manual?

Kit Walker Posted at 2015-10-7 14:58
I've done the same thing, a few times with no problems.
Can anyone explain why it's not ok to fly. ...

I believe it is all in the voltage.  Not in what percent the device is saying is left.  Make sure your voltage is being displayed on the device right under the percentage.  If that  green voltage color turns orange bring her back because if it goes to the next step it will try to land on its own.

So if you have 60% battery when you take off, what is the voltage?  That is the thing to watch.    Next time watch the voltage and see what it was when you land and wait 10 minutes.  Then take off and go up 50 feet and look at the voltage.  It usually drops rather quickly and then slightly starts rising a little before it levels off.   I watch my voltage as much as I watch where I am flying.  If I remember correctly it will turn orange before it gets to 3.60 volts then turn red at or near 3.60   The trick is to not let it get to 3.60.   If you look at the battery screen it will show all four cells.  Then there is a toggle to show voltage on the main screen.  This will show the lowest voltage of the cells on the main screen.

Phantom 3 is not The Battery Game - its Aircraft Game. There is so clever battery unit with a chip  and 160$ - not a trifles. So is it defect battery unit or software incorrect interpretation or both. Anyway I'm waiting for DJI reply.

Sir Edward K Posted at 2015-10-8 08:04
I believe it is all in the voltage.  Not in what percent the device is saying is left.  Make sure y ...

I do check my voltage, and have it shown on the main screen. Thanks for the info but. I wasn't aware of this a month ago.

I guess I was assuming the OP was already aware of this.., and was wondering why a 10 minute rest would decrease the battery life, power or voltage. (Assuming all cells are healthy)
It just seems like I should NEVER land and re fly in any circumstance. Even if for a 1 minute rest.
If so.., this is another peice of VERY important information that everyone should be aware of.

Kit Walker Posted at 2015-10-7 17:40
I do check my voltage, and have it shown on the main screen. Thanks for the info but. I wasn't awar ...

I am not sure it is a problem for a rest as you are using it (right back up).  But to pack up and let the battery get cold drive to another location and fly with a couple hours between might pose the problem.

I have had my voltage on a battery I charged fully but did not use for two days drop to color orange after about 5 minutes.  I think it was showing like 3.65 voltage but my battery was 75% at the time.   That is when I started putting them back on the charger if I did not fly them within 24 hours of the full charge. And really watching my voltage.

By the way thanks for the help with premiere pro.  I have used it a lot since then.  I think I might just purchase a subscription for it.

Sir Edward K Posted at 2015-10-7 23:54
I am not sure it is a problem for a rest as you are using it (right back up).  But to pack up and  ...

Stopping for 10-15m should not be an issue it the longer resting time that is the problem, i have flown many packs from 50% TO 20%after a few days before recharging them to full with out problem but DJI do not recommend it,

DJI state to only fly from 100% charge down but a pack can not just loose its remaining charge with out reason.

Wow I am interested to here what DJI says.

Sir Edward K Posted at 2015-10-7 17:54
I am not sure it is a problem for a rest as you are using it (right back up).  But to pack up and l ...

That is when I started putting them back on the charger if I did not fly them within 24 hours of the full charge.

Topping them off without using them is specifically NOT recommended in the care and feeding of Lithium battery chemistry.  

i,v had My first crach!
Does the batteri need to discharged completely whith stand on the ground?some batteris have "memory"so the battery nerver goes fullt loaded.if you start loading the battery evetytime whith 50-60 power on IT.
Hope you understand My pore english.

I need to send logs from crashed Phantom, and when I connect aircraft to the PC, turn on Read Flight Mode (on the mobile app) it shows up as Unknown USB device. I have tried another cables, other PC, plug in to my MacBook, restart aircraft, RC, application. Reinstall USB host drivers. No success. Have anyone idea to get the logs?
Also I have checked the battery health, it is 100%, 33 charge times, and 32% charge (first connect after crash).

I think everybody of us is aware of how a Lithium battery should work and should be treated but I also came to the conclusion that this does not fully apply to the Phantom battery, for whatever reason. Maybe because the battery for an aircraft is much more complex than a battery for a cell phone, maybe DJI technology is not sophisticated enough, who knows, we can start a long list of speculation again.
Fact is: it just doesn't seem to work as it does with a cell phone. When my cell phone indicates 60% or 50% or even 20% battery, I still make phone calls. That apparently does not work with the Phantom.

As Edward has pointed out, also in another thread in which I contributed my critically low voltage experience, it looks like you really should start with always 100%, with one hour breaks probably tolerable. I started with 65% and after one minute I got a critically low power with auto landing at 62%. I didn't crash as I had the weird feeling that this might happen and the Phantom was very close and I was still able to steer the Phantom back to where I was.

My learning: I would fly a battery with 50% left only if I have a one or maybe two hour break. Two hour break I would probably start to be very careful. In any other case, less power left or longer breaks, I would leave the battery and recharge it when I know I will fly that battery within the next 24 hours.

Again, we can discuss if that is how a lithium battery should work and we probably get a lot of answers saying no. But it's just the way it is.

That's my opinion, probably reflecting Edward K's, sorry SIR Edward K's opinion

I also think that new pilots should be made much more aware of behavior like that. Sorry for that experience grigorriy!

I would not trust the battery percentage (top right) as I've had the opposite problem. Full charge, flew for 10 mins with battery down to 48%.  Next week charged to 100% went to fly and the Dji app and p3p stated 48%. I did check the battery state on the main Dji battery screen and they all stated 100% on all cells so decided to fly. Got  a full flight with the normal 30% warning after 18mins or so.

Recharged again and both app and p3p back to normal. I did notice looking at the flight log on health drones I had one cell I had many more deviations which have been gradually decreasing on every charge since this incident.

I now charge my battery to 100% from whatever is left from the last flight.

Cell voltage is not the same if the battery is hot or cold. On my last flight, I landed at 36% battery, 3,62V (lowest cell value indicated in yellow on the main screen), all cells equal.
Back home, the battery was cold and when I powered on the quad, I had 37% battery and... 3,78V on all cells (green on the main screen)
I never takeoff below 95% and never do 2 short flights on the same battery.

grigorriy Posted at 2015-10-15 16:09
I need to send logs from crashed Phantom, and when I connect aircraft to the PC, turn on Read Flight ...

I'm very concerned about this problem, as pretty much the exact same thing happened to me.  

Did you succeed in getting ANY responses from DJI?

DJI care of me from my first email. I send them some technical and descriptive information about fly and crash. Without tech. logs from quad. And now I'm waiting for their decision and response.
Here is my log from mobile device (Android) http://healthydrones.com/main?fl ... ENERALNotifications
We can see some cell warnings during the fly.
Is it different logs from mobile and Phantom memory?

A number of people have reported similar events when the battery is not pushed in all the way - and/or when the battery or telemetry pins are dirty.

Use DeOX gold on the battery pins and always make sure the battery is fully seated.

I'm not saying this is the problem in this thread - just putting the information out there for those who may want to avoid battery problems.