Please select Into the mobile phone version | Continue to access the computer ver.
Mini 2 lost in the ocean, Battery died, Wind 14mph? LOGS. UPDATE
12Next >
2343 70 2020-11-18
Uploading and Loding Picture ...(0/1)
o(^-^)o
djiuser_s235TQXSXtNO
lvl.2
Flight distance : 489026 ft
United States
Offline

Thank you DJI Stephen, JJB, Labroides, ABeardedItalian, and all the others for your detailed replies! I did not add enough information and have replied below and will add more info now!
DJIFlightRecord and Dat https://drive.google.com/drive/folders/1x4m3fuVEviTwQ9eTyRbdEw_nvi5_1uvB?usp=sharing
App airdata log: https://app.airdata.com/share/UIXaJX/GENERAL
Phantom help https://www.phantomhelp.com/logviewer/ZO9YVHHKUZ2OU61BFWQ3/

I have flown other drones before and use as many wind signs and tools that I feel are safe. UAV app, google weather, palm trees, hotel flags, etc. EVEN RETURN tests during flight (@3m20s I returned east at 14-15mph).
Further more knowing the wind is South south east I tried to use the wind to return south on the beach from my orginal starting point.
@ 7m5s 67% battery I turned around heading eastish reaching 6mph.

@ 7m54s 58% battery I start heading slightly south reaching 10mph.

@ 8m16s 54% battery my south direction is working and I reach speeds of 14-20mph almost the way back.

@ 11m18s 23% battery I drop to 10mph for a few seconds but cut south more returning to 20mphs.

@ 13m1s 8% battery my speed rapidly goes from 13mph down to 6mph.

Somewhere around 10% battery I switched to sports mode and tried to now head directly east at my last attempt home.
@13m22s 6% battery I am full throttle east toward the beach but now so close the the coast and BlackRock (cove like structuer?) the wind is drifting me south.

@14m 29s 0% battery my hope is lost and I take a phone screenshot and I know he did his best!
I do still feel my battery drained fast after returning home @67% 7m5s. My flight out was 19-22mph, most of my return was 15-22mph as I angled with the wind as much as I could.

Screenshot_20201118_150201_dji.go.v5.jpg


Last video during last flight, Cached!










--------------------------------------------------------------
ORIGINAL POST
Anyone else lose their poor little drone?

I started my return at 67% battery, 7 Minutes 4 seconds and my flight ended in the water at 16minutes 4 seconds.

DJI estimated flight time is all over the place btw...
I didn't exactly trust it but my dji flight log showed:
At 2min 29s I was at 91% battery with 28m28s left.
At 3min 20s I was at 88% battery with 16m26s left.
At 6min 13s I was at 75% Battery with 18m43s left.
At 6min 47s I was at 70% battery with ONLY 7m7s left. So I started my return.
At 8min 38s I was at 51% batteru with only 4m24s left. I knew it was a 50/50 chance.
At 10 min 38s I was at 29% battery with only 2m42s left.
At 12min 51s I was at 9% battery with only 1m11s left. It was over.

Wind was only 14mph.

Screenshot_20201118_151504_com.uavforecast.jpg

I was really hoping the Mini 2 would be better in the wind with the faster speed and level 5 wind scale rating. I was even as safe as I could knowing to return at around 70% battery.






2020-11-18
Use props
DJI Stephen
Super Moderator

Offline

Hello there. I am sorry to read and to know what happened to your DJI Mini 2. Since this unfortunate incident happened and you have lost the said drone. I would recommend for you to contact our DJI Support Team at https://www.dji.com/support?site=brandsite&from=nav for further assistance. We have a team that will do there best to help you and give out the best resolution for the said issue. Again, I am sorry for your loss and thank you for your understanding.
2020-11-18
Use props
JJB*
Captain
Flight distance : 4575374 ft
  • >>>
Netherlands
Offline

Hi,

Sorry for your MM2 loss, amazing distance travelled btw : 6670 meters.

The RTH countdown was cancelled (red cross in the chart) by you, fly back home yourself.
But you lost some direction towards HP, see the chart.
If i draw the line straight back home from the red cross, think your MM2 landed in at the spot near you.

cheers
JJB

analysis1.png
2020-11-18
Use props
Suren
Captain
Flight distance : 7737779 ft
  • >>>
New Zealand
Offline

Hey Mate, so sorry for the loss of your drone. Looking at Airdata, your app must have been screming  wind warnings - why did you not turnaround and fly back when you were getting these warnings at almost 1km out?
2020-11-19
Use props
DAFlys
Captain
Flight distance : 1155026 ft
United Kingdom
Offline

Try looking at your log here it usually has more detail than airdate - http://phantomhelp.com/logviewer/
2020-11-19
Use props
Labroides
Captain
Flight distance : 9991457 ft
Australia
Offline

Wind was only 14mph.
Correction .. your wind forecast app suggested the wind speed might have been 14mph.
But there are lots of reasons that the actual wind at your flying site could be significantly different.
Forecasts are just forecasts, not the actual wind.

Your mishap was due to not paying attention to the wind direction and how it would affect your return flight.

You flew almost two miles out with a tailwind..
Your choice meant you would have to fight against a headwind to get back.
You can see what was going on and how the flight progressed here:
https://www.phantomhelp.com/logviewer/ZO9YVHHKUZ2OU61BFWQ3/

Your drone made an easy 21-22 mph heading out.
You turned and pointed toward the home point but with full stick your drone was only able to make 6-8 mph against the headwind.

You turned to face the drone toward a point about 0.6 miles south of the homepoint (was that intentional?)
Now the drone wasn't facing the wind head-on and it was able to reach 14-17 mph.
Later you turned further south and picked up more speed, but were heading even further away.
By the time the battery hit 15%, the drone was still almost a mile from home.
But at 13 minutes with the battery at 7% you turned even further from home and also away from the shortest path to land.Flying further south, the battery ran out with the drone nearly a mile from home and 1500 ft from the nearest land.

I was really hoping the Mini 2 would be better in the wind with the faster speed and level 5 wind scale rating.
If you push against a headwind, you have to subtract the windspeed from the drone's top speed.
Which means the drone can only make 7mph pushing against a 14 mph feadwind.

And if you are two miles out, that still means a slow trip home.
You could have checked by flying a short distance against the wind before heading offshore to see how fast you could fly into the wind.

I was even as safe as I could knowing to return at around 70% battery.
That's not much help when you can't steer a straight course towards home
If you want to fly offshore, you need a lot more awareness and caution because there's no room for mistakes out there.






2020-11-19
Use props
ABeardedItalian
First Officer
Flight distance : 1034633 ft
United States
Offline

Was this your first drone? First time flying?

UAV forcast, Ventusky, others are only points of reference for wind, unless you measured the wind where you were standing the numbers these app's report are only an Estimate at"There Location" meaning the wind where you are could be very different.

Whatever the app reports the wind to be at ground level, double it for every 100 feet. The wind only increases in strength the higher you go up, so even on calm day's with no wind at 100ft it could be a very different story and you won't have any visual indicator unless a high wind warning is prompted.

Your battery estimations were fluxing because the mini was battling strong winds, it was figuring out how much energy was needed to fight the wind. These kinds of winds will Eat your battery life away as your drone spends more then half it's flight just trying to keep it's position.

------------------

You started the motors before letting the home point be set, it's best to wait for the HP to be set before take off. Many mini's have been lost by HomePoint being set after take off and in the Event of an RTH the drone fly's out to sea because the HP direction was set mid flight.

While the mini 2 is a great drone it's not necessarily for beginners, many have been RAVING about the mini 2's wind capabilities but many of these posts/videos are comparing it against a known rating. They either had the mini 1 or have other drones to compare it's abilities against, a new pilot getting started hearing how well it handles the wind is a recipe for destruction. These new pilots are unaware of the dangers of flying in any wind let alone high winds with the mini, were going to see more posts like these of people buying the mini 2 thinking it has world class wind resistance only to be lost by a strong sea breeze.

I'm sorry to hear about your loss OP but this could have been prevented with a little reading or video watching.
2020-11-19
Use props
Labroides
Captain
Flight distance : 9991457 ft
Australia
Offline

ABeardedItalian Posted at 11-19 02:00
Was this your first drone? First time flying?

UAV forcast, Ventusky, others are only points of reference for wind, unless you measured the wind where you were standing the numbers these app's report are only an Estimate at"There Location" meaning the wind where you are could be very different.

You started the motors before letting the home point be set
That's not what the data shows.
2020-11-19
Use props
djiuser_jlXvtbqzCyHi
Second Officer
Flight distance : 3351978 ft
Spain
Offline

I'm sorry for your lost!! But unfortunately it looks / sounds like an pilot error......hopefully you have the chance to get a new drone......
2020-11-19
Use props
AdmBenson
lvl.3
France
Offline

Why 13 mn flight time only with a full charged battery ?
That's the supposed flight time in sport mode ?
2020-11-19
Use props
Labroides
Captain
Flight distance : 9991457 ft
Australia
Offline

AdmBenson Posted at 11-19 03:50
Why 13 mn flight time only with a full charged battery ?
That's the supposed flight time in sport mode ?

Because he was flying at full stick against a headwind.
Your car doesn't get good fuel economy if you drive at full speed up a high mountain.
2020-11-19
Use props
AdmBenson
lvl.3
France
Offline

I ask my question again: What is the supposed flight time of the Mini 2 at full speed in sport mode ?
I think it's good to know if it's less than 10 mn...
I mean. I got a P3P, an Inspire pro, a Mavic pro, I've never seen a so big difference of autonomy between min and max load

Actually, in this particular case, looking at the logs it's even worse: from 70% to 0% in 6 mn only :/
good to know if it's normal...
2020-11-19
Use props
Labroides
Captain
Flight distance : 9991457 ft
Australia
Offline

AdmBenson Posted at 11-19 04:06
I ask my question again: What is the supposed flight time of the Mini 2 at full speed in sport mode ?
I think it's good to know if it's less than 10 mn...
I mean. I got a P3P, an Inspire pro, a Mavic pro, I've never seen a so big difference of autonomy between min and max load

It's completely normal, but there's a lot more to the loss of this drone if you read my first post.
2020-11-19
Use props
AdmBenson
lvl.3
France
Offline

Okay. I got recently a Mini 2, don't use to fly so little drones
I guess that this little thing will fly most of the time close to its limits, and therefore its realistic autonomy is more something like 10-15 mn in (compatible) windy conditions.
Good to know
2020-11-19
Use props
JJB*
Captain
Flight distance : 4575374 ft
  • >>>
Netherlands
Offline

Hi,

Another interesting issue is the power a MM2 has after 20% batt juice left.
See the data in the chart.

Even with head and cross wind this MM made 20 mph! After 20% speed reduces while still 100% forward stick. See the speed line, speed in MPH.

If you like cloud upload your DAT (also on your mob device) file for this flight, it has wind data in there.

cheers
JJB
analysis2.png
2020-11-19
Use props
Chrismm
lvl.2
Flight distance : 489026 ft
United States
Offline

JJB* Posted at 11-18 23:57
Hi,

Sorry for your MM2 loss, amazing distance travelled btw : 6670 meters.

Thank you for the reply and EVERYONE ELSE (I will be replying to a few and adding more info).

You are correct, I did cancel the RTH that started around 2m 08s.
I tested return speed at 3m 18s and speed reached 15mph.

I did lose direction toward home as you mention. I started to battle the wind at points reaching only 10mph and decided to go with the wind and land on the beach south of where I had launched.
At 11m 4s I was at 20mph but dropped to 10mph in a few seconds.
At 11m 23s I angled south to fight less of the SSW wind in attempt to land on the southern part of the beach.
Attching DJIFlightRecord and FLY011.DAT file , (Is this what you were looking for?)
https://drive.google.com/drive/folders/1x4m3fuVEviTwQ9eTyRbdEw_nvi5_1uvB?usp=sharing

Thanks again!
2020-11-19
Use props
Chrismm
lvl.2
Flight distance : 489026 ft
United States
Offline

Labroides Posted at 11-19 01:35
Wind was only 14mph.
Correction .. your wind forecast app suggested the wind speed might have been 14mph.
But there are lots of reasons that the actual wind at your flying site could be significantly different.

THANK YOU for the detailed reply!

I will reply as best I can ( I did have some trouble finding the exact points you mention without time references)

For me to say the "Wind was only 14mph" may not have been fair to the scenario. I work on the beach and have to take down umbrellas, once it reaches over 15mph.
I do try to use all the info available to me, google weather, UAV app, palm trees and flags on the hotels nearby. (which is very different to the wind over the water between 3 islands, Moloka'i, Lanai, and Maui.)

Flight log. The wind seemed to generally be South southwest. It was only a slight tailwind? I did figure I would have to fight a little of the wind as you may have noticed I tried to go with the south wind back to land on the beach.

The only point I turned to test the wind was at 3m 20s and I reached 14-15mph heading back.
Yes at 7m 17s I was around 6mph heading back.

At 7m 55s I angled south and picked up speed from 10-20mph.

My goal was to go with the wind and land south on the beach. Every time I faced directly east to the beach my speed was severely reduced, so I angled south slightly.

At 11m 9s my speed started to slow to 10mph, and at 11m 24s I angled south reaching 20mph.
At 13m 1s my speed drastically slowed to 6mph and I was facing directly east toward the beach.
At 13m 19s you may notice I was full throttle forward heading east but making almost no progress and drifting south. (I assume this is because I reaching BlackRock and the wind is pushing off of it like a little cove?)

Last 2 quotes.
When I started flying I thought the wind was South south east from the UAV app and all the signs around me.
I again even tested the wind at 3m 20s (reaching a return speed of 14-15mph).
Lastly I used the south wind to reach return speeds up to 20mph which was the best I could do and try to land south on the beach.
Looking back the BlackRock half -like-cove I think was the nail in the coffin.?.

Thanks again for your reply and I hope I explained better my attempt to measure the wind and return with the south wind back on the beach south of where I had launched!!



2020-11-19
Use props
JJB*
Captain
Flight distance : 4575374 ft
  • >>>
Netherlands
Offline

Chrismm Posted at 11-19 09:07
Thank you for the reply and EVERYONE ELSE (I will be replying to a few and adding more info).

You are correct, I did cancel the RTH that started around 2m 08s.

Hi Chris,

Cannot download your DAT from google drive, simply does not work.
Any other link possible?  wetransfer.com to jjbsoftware@gmail.com?  or any other something  ;-)

cheers
JJB
2020-11-19
Use props
A J
Captain
Flight distance : 13838848 ft
  • >>>
United Kingdom
Offline

Sorry to read that
2020-11-19
Use props
Chrismm
lvl.2
Flight distance : 489026 ft
United States
Offline

ABeardedItalian Posted at 11-19 02:00
Was this your first drone? First time flying?

UAV forcast, Ventusky, others are only points of reference for wind, unless you measured the wind where you were standing the numbers these app's report are only an Estimate at"There Location" meaning the wind where you are could be very different.

THANK YOU FOR YOUR REPLY!

I have flown other drones, P4P, Mavic, Air, MP2, and Mini1.

Yes I did not explain enough. I do mostly use UAV for reference along with google weather, palm trees, flags on hotels nearby and I even TEST return home speeds (3minutes 20 seconds, I was fine at 14-15mph directly east return direction).

I detailed more of my wind circumstances in a previous posts (inbetween islands +BlackRock cove like structure).

The battery estimation I felt like was a problem because, #1 I took in all wind conditions near me that I felt I could, #2 I tested return flight at 3m20s, #3 I started return at 7m 3s 67% battery.

I further think the estimation was an issue because their may have been something wrong with the battery? I always flew with the wind to some degree and heading out I was around 20 mph and returning I used the wind at was mostly between 15-20mph again.

-----------
I did start the motors but the home point was set before I flew away from me. The Phantom log shows it https://www.phantomhelp.com/logviewer/ZO9YVHHKUZ2OU61BFWQ3/

And thank you again for your reply and condolences!
2020-11-19
Use props
JohnLietzke
First Officer
Flight distance : 2746864 ft
United States
Offline

Wind can dramatically change at different altitudes and due geographical attributes. Sport mode to fight the wind resistance consumes battery at a very high rate.

The Mini and Mini 2 do not have same ability as the Pro/Zoom or Air 2 to power through wind. The power and weight of the larger drones make it less susceptible to wind.

But a 20mph listed head wind consume battery very fast.  If the forecast suggested the wind would 20mph that may not account for gust different locations and altitude.

It appears to me after viewing your logs that you pushed the little guy far beyond his limits.
2020-11-19
Use props
Chrismm
lvl.2
Flight distance : 489026 ft
United States
Offline

JohnLietzke Posted at 11-19 13:32
Wind can dramatically change at different altitudes and due geographical attributes. Sport mode to fight the wind resistance consumes battery at a very high rate.

The Mini and Mini 2 do not have same ability as the Pro/Zoom or Air 2 to power through wind. The power and weight of the larger drones make it less susceptible to wind.

Hi thank you for the reply. And yes there is always more to learn for everyone! ))

Where did you see a 20mph listed head wind?
Sports mode was not activated until around 10% battery.
The log shows I did not fly into a head wind, but more of a cross wind.  20mph flying out, 15-22 mph returning.

I left plenty of battery to return and even tested return conditions. I was just out of luck this time.
2020-11-19
Use props
JohnLietzke
First Officer
Flight distance : 2746864 ft
United States
Offline

Chrismm Posted at 11-19 14:00
Hi thank you for the reply. And yes there is always more to learn for everyone! ))

Where did you see a 20mph listed head wind?

On the weather chart posted it showed 20+ mph gusts.

You are right, it does indicate more of a cross wind but trying to return to your first Home Point would have given you a head wind as the wind direction was Southwest and your location was to the Northeast.   

I mentioned Sport mode because that is often a method used when strong winds are encountered.  And to note that the battery consumption is more rapid.  When fighting a cross wind, in my experience, drones seems to perform better in Sport mode and have less lateral drift.  But when you engaged it that battery was already very low.  

I have had my share of close calls with wind and battery even when the forecast said there was virtually no wind.  Especially around ocean, cliffs and mountains.  I empathize with your situation.
2020-11-19
Use props
trader6777
lvl.4
United States
Offline

I nearly lost my Mini 1 in a similar situation (over water, headwind on return).  I knew it would end up in the water if I brought it all the way back so I emergency landed on a beach 3,000 ft away.  An old lady who was walking thought it was abandoned and took it.  I posted lost drone signs and got it back a few days later.

So what lessons did I learn?
#1  Do not fly more then 11,500 ft over water from nearest dry land, my flight was 13,500 ft).
#2  Do not rely on battery % indicator over water.  My RTH was 72% battery and the wind drained it faster than I thought possible.
#3  If wind is draining your battery, drop as much altitude as possible!  I know flying 50 ft over the ocean is scary, but you won't be fighting as much wind.
#4  Put your phone number or email on your drone.  More often that not, people who find it will contact you, instead of keeping it.
2020-11-19
Use props
Labroides
Captain
Flight distance : 9991457 ft
Australia
Offline

Chrismm Posted at 11-19 09:50
THANK YOU for the detailed reply!

I will reply as best I can ( I did have some trouble finding the exact points you mention without time references)

I hope I explained better my attempt to measure the wind and return with the south wind back on the beach south of where I had launched!!
As it turned out, the wind estimate was probably close to the actual wind encountered.
But that made no difference to the outcome.
Your test at 3:20 (0.8 miles out) gave a misleading indication of the potential return speed.
Your second test at ~7:20 (1.9 miles out) showed you had to deal with a much stronger wind further out.

Some rough calculations on battery burn rate, speed and distance suggest that if you had persisted with flying straight back toward the homepoint, you might have just made it back safely.
If the wind speed decreased closer to shore, you probably would have made it.
But steering off to the southeast ensured that the drone was never going to reach shore before the battery ran out.

Flying out to sea with a tailwind can be a risky venture .
Flying too far offshore with a tailwind is always going to end badly.




2020-11-19
Use props
David Martin Graff
Captain
Flight distance : 38060446 ft
  • >>>
United States
Offline

Sorry to hear about your loss, the Mini 2 around turbulent waters with high wind advisory should be taken with high caution.
2020-11-19
Use props
Suren
Captain
Flight distance : 7737779 ft
  • >>>
New Zealand
Offline

That poor mini, that video shot how windy it was and that poor drone was fighting for its life trying to return. Pilot error mate accept it, learn the lesson and move on.
2020-11-19
Use props
gfab71
Captain
Flight distance : 279429 ft
Italy
Offline

AdmBenson Posted at 11-19 04:57
Okay. I got recently a Mini 2, don't use to fly so little drones
I guess that this little thing will fly most of the time close to its limits, and therefore its realistic autonomy is more something like 10-15 mn in (compatible) windy conditions.
Good to know

The batteries need some charging cycles and subsequent use, before having their optimal performances.
If the battery he used was brand new (first use) and never used and recharged, maybe this could also be one of the reasons of the short duration flight time, moreover in such special conditions, against strong wind and with a great flight distance.
May have had a stressful use as the first time ..

31 minutes of estimated duration is understood i think in normal conditions with calm wind and quiet flight.
It is obvious that if you fly against the wind with moderate or strong winds, or if you set for example sport mode,
the duration decreases significantly due to the greater power (and consumption) required by the engines.
2020-11-20
Use props
FloridaNext
Second Officer
Flight distance : 58320 ft
Germany
Offline

gfab71 Posted at 11-20 08:35
The batteries need some charging cycles and subsequent use, before having their optimal performances.
If the battery he used was brand new (first use) and never used and recharged, maybe this could also be one of the reasons of the short duration flight time, moreover in such special conditions, against strong wind and with a great flight distance.
May have had a stressful use as the first time ..

I don't believe that a battery gets any better after some charging cycles, it's a rumor. There was a comprehensive article in the internet which researched exactly into that. It showed that a battery degrades already with the very first charging cycle with no improvement whatsoever. I can't find it right now and I don't even remember whether it was in german or english. But it was made pretty professional.
2020-11-20
Use props
Chrismm
lvl.2
Flight distance : 489026 ft
United States
Offline

FloridaNext Posted at 11-20 10:04
I don't believe that a battery gets any better after some charging cycles, it's a rumor. There was a comprehensive article in the internet which researched exactly into that. It showed that a battery degrades already with the very first charging cycle with no improvement whatsoever. I can't find it right now and I don't even remember whether it was in german or english. But it was made pretty professional.

Agreed, I always thought that maybe,,,,,,,,,, but until I see someone test multiple batteries and show the first 10 charge cycles (in a windless room at the same temperature, etc etc). I wont 100% believe it XD.
2020-11-20
Use props
rwynant V1
Captain
Flight distance : 4842277 ft
  • >>>
United States
Offline

Chrismm Posted at 11-19 14:00
Hi thank you for the reply. And yes there is always more to learn for everyone! ))

Where did you see a 20mph listed head wind?

If I may ask,  how many charge cycles on that battery?

The reason I ask,  is brand new Lithium batteries need several charge cycles for them to be at their best performance for power and longevity.

But fighting that wind is just a bad plan.  The diameter of the props on the little bird is just not moving enough air to fight that wind.

Aerial Traffic
Randy
2020-11-20
Use props
TDZHDTV
First Officer
Flight distance : 2068550 ft
United Kingdom
Offline

gfab71 Posted at 11-20 08:35
The batteries need some charging cycles and subsequent use, before having their optimal performances.
If the battery he used was brand new (first use) and never used and recharged, maybe this could also be one of the reasons of the short duration flight time, moreover in such special conditions, against strong wind and with a great flight distance.
May have had a stressful use as the first time ..

21 - 22 minutes is the norm for Mavic Mini and Mini 2, you can’t get anywhere near 30 mins outside
2020-11-20
Use props
Chrismm
lvl.2
Flight distance : 489026 ft
United States
Offline

rwynant V1 Posted at 11-20 14:47
If I may ask,  how many charge cycles on that battery?

The reason I ask,  is brand new Lithium batteries need several charge cycles for them to be at their best performance for power and longevity.

3rd flight. I think I reused one of the batteries, so 1 charge cycle.

I tried to google this and could not find any info on Lithium batteries needing a few charge cycles. Any idea where to find such info?
2020-11-20
Use props
rwynant V1
Captain
Flight distance : 4842277 ft
  • >>>
United States
Offline

Chrismm Posted at 11-20 17:00
3rd flight. I think I reused one of the batteries, so 1 charge cycle.

I tried to google this and could not find any info on Lithium batteries needing a few charge cycles. Any idea where to find such info?

10 Years experience and knowing RC electric gurus who KNOW!   It is written somwhere, but where I do not know.

Test with caution, watch your cell voltages, and DO NOT rely only on Battery Percentage.

TODAY I have an M2Pro battery read 91%.....I then put her in the air......under load the cells were reading 3.65v each......landed and took off again......92%,   3.7v per cell......3.7 under load is about 40% maybe less.

Aerial Traffic
Randy
2020-11-21
Use props
Chrismm
lvl.2
Flight distance : 489026 ft
United States
Offline

rwynant V1 Posted at 11-21 18:30
10 Years experience and knowing RC electric gurus who KNOW!   It is written somwhere, but where I do not know.

Test with caution, watch your cell voltages, and DO NOT rely only on Battery Percentage.

Thanks.

So from my log -- https://www.phantomhelp.com/logviewer/ZO9YVHHKUZ2OU61BFWQ3/

How far off would you say any of these percentages are? And should I look at total or each cell??

I started at 8.666V. (99%)
@20 seconds in 8.439V. (98%battery)
@3min20s 7.948V (88% battery)
@7min5s 7.708V (67% battery)
@8m 44s 7.388V (50% battery)

@10m 31s 7.215V (31% battery)
@14m 25s 7.215V (0%battery)

@15m 51s 7.098V (0 %battery)
@16m 4s 7.098V (0% battery)




2020-11-23
Use props
K6CCC
First Officer
Flight distance : 631224 ft
United States
Offline

Sorry for your loss.  Standard recommendation if you need to fly in windy conditions.  Fly out against the wind so you have the wind at your back on the return flight.
2020-11-23
Use props
rwynant V1
Captain
Flight distance : 4842277 ft
  • >>>
United States
Offline

Chrismm Posted at 11-23 13:38
Thanks.

So from my log -- https://www.phantomhelp.com/logviewer/ZO9YVHHKUZ2OU61BFWQ3/

Each cell.....

50% battery left the cells should read about 3.8vdc each, or 7.6vdc total.....you were reading 7.3x total

The % system by DJI always seems to be off a little, sometimes alot.  In this case it looks like the little bird was simply working so hard, she ran out of battery much sooner that one would think.

I am sorry you lost your AC.

Randy
2020-11-23
Use props
akozc
First Officer
Flight distance : 931381 ft
Japan
Offline

sorry for  loosing  your MM2.
I do not enter too detail but that choppy sea already giving a warning for high wind speed at the  location where your MM2 was flying or lost.
I agree with other commentators,  neither of the wind speed apps could give you a precise speed , as those data are all collected by meteo stations and may not represent the current wind
specially on the sea where the  wind direction and speed could be drastically and abruptly  changes.
I ,therefore ,never ever fly even my M2P over the sea if choppy waves are clearly visible from any distance.
Nevertheless ,consider it as a lesson to learn
2020-11-30
Use props
AdmBenson
lvl.3
France
Offline

1/ What is the discharge curve of a "good" battery for the Mini2 ? I mean , Volts = f(time) for different sink currents ?

2/ Is there a way to calibrate the % displayed, as for example for the Inspire ?

I remember in the past some issues with drones falling from the sky due to operators trusting a wrong % display while the voltage was down
Also about drones falling from the sky due to overcurrent/thermal protection of the motors switching off the main power supply of the drone
I'm still surprised by an autonomy of 14 mn in the described conditions (50% at low load, 25 % at max load in normal mode and 25% at max load in sport mode - if I'm not wrong)
Still not convinced that it's an operator error. I think something was wrong with the battery
2020-11-30
Use props
Labroides
Captain
Flight distance : 9991457 ft
Australia
Offline

AdmBenson Posted at 11-30 08:03
1/ What is the discharge curve of a "good" battery for the Mini2 ? I mean , Volts = f(time) for different sink currents ?

2/ Is there a way to calibrate the % displayed, as for example for the Inspire ?

2/ Is there a way to calibrate the % displayed, as for example for the Inspire ?
No there isn't (and probably wasn't for the Inspire either)


Still not convinced that it's an operator error. I think something was wrong with the battery
It's very, very clearly operator error.
He flew out too far with a tailwind, wasn't able to make good speed directly into the headwind when out at sea, and then steered off where the drone was never going to reach land before the battery ran out.

2020-11-30
Use props
12Next >
Advanced
You need to log in before you can reply Login | Register now

Credit Rules