I got a critically low voltage warning when the battery still have 58%, the aircraft start to land immediatley!!
I have saw some other people having a similar issues in another thread too..

My aircraft firmware  version is 1.4 and I am using Ipad Mini 4 with IOS 9.02. Do you think this is another IOS 9 Issues??

I fid it strange that you only charged it 19 times and you are already down to 89 percent life on the battery.  I am over 45 and mine just clicked down to 99 percent life left.  You have to watch the voltage.  You have your voltage toggled off so you can't see it while you are flying.   Did you start with a full charge?  

Sir Edward K Posted at 2015-10-6 01:44
I fid it strange that you only charged it 19 times and you are already down to 89 percent life on th ...

Nope , it start it with around 75% of charge.

Have you download your flight log to healthydrones.com?
Have you recharged your battery and flown again?

kbjyin@gmail.co Posted at 2015-10-5 12:49
Nope , it start it with around 75% of charge.

I have seen a lot of cases where this is happening if you start off with less than a fully charged battery.  If you go by the book they say alway fly with full charge battery.   The voltage is the problem. It can say 3.66 while it is on the ground but if you put it through stress like liftoff that voltage can dip to critical.

Phantom Pilots Forum have talked about it some.

CFM01 Posted at 2015-10-6 01:49
Have you download your flight log to healthydrones.com?
Have you recharged your battery and flown ag ...

not yet, but I have attached the flight log with this thread again..

Sir Edward K Posted at 2015-10-6 01:59
I have seen a lot of cases where this is happening if you start off with less than a fully charged ...

Thanks for the tip, but I have fly it without full charge many times and this is the first time I see this errors after I use an IOS 9 device.. Not sure they are related  or not..

kbjyin@gmail.co Posted at 2015-10-5 13:22
Thanks for the tip, but I have fly it without full charge many times and this is the first time I  ...

And maybe that is why your battery life expectancy is dropping fast.   Just a thought.

Holy c__p you were over water when it happened and you had your wife with you standing near railing by the water (wow healthy drones show a lot!).  What a time to have that happen.  I looked at your logs and saw the warning while you were out over the water.  But your battery itself did not show any signs that something was going on (HealthyDrones).  No major deviations found.   Very interesting.  Did you have to fight it hard to make it not land?

Sir Edward K Posted at 2015-10-6 05:44
Holy c__p you were over water when it happened and you had your wife with you standing near railing  ...

Yes, You bet! It scare me out when it decided to land over water all of a sudden.. Am glad the drone was landed safely finally ..  

kbjyin@gmail.co Posted at 2015-10-6 05:22
Thanks for the tip, but I have fly it without full charge many times and this is the first time I  ...

Just to answer the other part of your question, no, iOS 9 has nothing to do with the issue.

Sir Edward K Posted at 2015-10-6 05:44
Holy c__p you were over water when it happened and you had your wife with you standing near railing  ...

Can you or the original poster please share the link for this incident's log on HealthyDrones?  I'd like to get better at reading them.  I'm also curious as I had a similar critical battery problem.

Thanks.

Bluevista Posted at 2015-10-7 14:33
Can you or the original poster please share the link for this incident's log on HealthyDrones?  I' ...

sorry, it looks like he removed the flight log that was posted in the initial post.  I looked at it on healthy drones and did not see anything battery related that should have gave him this warning.   But I deleted it as it was not mine.

But I did save some things in text document about it because I am keeping track:

General:
Flight time 03m 52s
Takeoff Battery 76%
Landing Battery 58%
P3A/iOS DJI 2.2.0

Battery:
Manufactured: 20-Jun-2015
Battery life 89%
Min Temperature 80.5f
Max Temperature 102.1f
Times charged 19

Flight time 03m 50s
Total Mileage 3,422 ft
Max Height 489.5 ft

Minor Deviations
Cell 1 - 2.8
Cell 2 - 0
Cell 3 - 4.1
Cell 4 - 2.1

Battery All Good No deviations found.

Tips:
A        00m 00s        0.0 ft        0 ft        Mode        Mode changed to GPS_Atti
B        00m 02s        0.0 ft        0 ft        Mode        Mode changed to AssitedTakeoff
C        00m 02s        0.0 ft        0 ft        Tip        Tips__RC Assisted Takeoff
D        00m 08s        0.0 ft        0 ft        Mode        Mode changed to GPS_Atti
E        00m 55s        468.5 ft        1,286 ft        Mode        Mode changed to AutoLanding
F        00m 55s        468.5 ft        1,286 ft        Tip        Tips__Critically low power, the aircraft will land now. You can throttle up to reduce the speed of d
G        02m 14s        32.2 ft        26 ft        Mode        Mode changed to GPS_Atti
H        03m 36s        6.9 ft        3 ft        Data Loss        Downlink data connection lost for 1.1 seconds
I        03m 41s        6.9 ft        3 ft        Data Loss        Downlink data connection lost for 1.9 seconds

Sir Edward K Posted at 2015-10-7 22:37
sorry, it looks like he removed the flight log that was posted in the initial post.  I looked at it ...

that looks like a bug in the FW,

DJI Dave can you Pass this one Up to be looked at as its a little worrying.

@kbjyin, I think I read another one of your posts from last month.  Did you drop a bird in the drink last month?  I was looking at the battery info from that flight and I had a thought.  Are you using the same battery you were using in that flight as well?  It had 12 charges then and I think 92% life.   If it is the same battery, Do not fly with that battery again!  I think there is something wrong with it even though Healthy drones did not show anything this time.  The last post you made when it fell into the sea, did show severe problems with the battery.

I recently experienced a very similar issue. Started flying with 62% battery charge, phantom 3 advanced with SW version aircraft 1.4.10, rc 1.3.20 and app 2.3.0 also using an iPad mini 4 with iOS  9.0.2.

Got a critically low power message, even though my battery still had 62% charge, and the drone changed to landing mode. I also had RTH enabled and didn't work, it just landed where it was.

Almost lost my drone because it was at around 150 ft away.

I had a similar situation happen today in conditions I've flown in many times before.  Healthy Drones shows some cell voltage issues.  However, I've seen these as well, and never had it autoland.  It was pretty scary that it decided to do so.  I was able to fly it back to me and it autolanded.  

http://healthydrones.com/main?share=NDQ1NTA&page_id=POWER

Has anyone resolved this issue?   LIke the OP, I had the same thing happen to me (Mavic 2 Pro) with a critical low battery warning (10%) yet the battery level was 58%.   I'm thinking the warning was actually in relation to the ipad mini battery level -- which was very low.    Does it make sense that the DJI Go 4 app monitor the external display battery level?

QUBO1234 Posted at 12-22 15:45
Has anyone resolved this issue?   LIke the OP, I had the same thing happen to me (Mavic 2 Pro) with a critical low battery warning (10%) yet the battery level was 58%.   I'm thinking the warning was actually in relation to the ipad mini battery level -- which was very low.    Does it make sense that the DJI Go 4 app monitor the external display battery level?

No.  Early auto landings are usually because either the battery is swollen or a cell is out of balance (low voltage) relative to the others.  

Good luck.

QUBO1234 Posted at 12-22 15:45
Has anyone resolved this issue?   LIke the OP, I had the same thing happen to me (Mavic 2 Pro) with a critical low battery warning (10%) yet the battery level was 58%.   I'm thinking the warning was actually in relation to the ipad mini battery level -- which was very low.    Does it make sense that the DJI Go 4 app monitor the external display battery level?

If you fly with a battery that isn't fully charged and hasn't been fully charged for a few days, The percentage it shows will not be what it says it is. The only time the percentage is correct is when you start with a fully charged battery.

You probably had this warning because some time had lapsed between your flights.  This has happened to me several times too.  I found out if you land, shut everything down, then restart, it solves the problem.

Thanks for the feedback on getting a 10% low battery critical warning with 58% battery remaining.   After getting home, using the same battery (no recharge), I flew around and all was normal.   Perhaps shutting it all down and restarting cleared some bug?  At any rate, I've recharged and used the battery a couple of times since and it seems ok.    Thanks for the feedback that DJI GO 4 app is not monitoring the ipad battery level (which was very low).