Hi folks

I was watching one of Henrik's videos and noticed that he took off from the sunroof of his car with his Mini 2.

I remember doing this once with my P4P and it very nearly ended up ''boobs'' up, the drone shot off to the left immediately
on takeoff, it didn't even get to its takeoff height, it rose a few feet and shot off at speed to the left and control of it was very difficult.
I did mention this in the P4P section a few years back and all was explained, I've never taken off anywhere near any metal since.

So, my question is, is the MM2 impervious to sources of metal as Henrik seems to believe or was I wrong letting him know the issues
of using this method? I thought sources of metal affected any drone with a compass? unless of course, the MM2 is heavily shielded?

It's not "sources of metal" that's a potential problem, it's having steel (or cables carrying live current), close enough to the drone's compass at power up to affect the compass which could cause the gyro sensor to get an incorrect directional value when it initialises with the compass values.

If he's far enough from steel, he'll have no problem.
If his drone's compass is too close, he could have a problem.

Perhaps he checks the orientation of the drone icon on his screen map to confirm that it's pointing in the same compass direction as the real drone is to confirm that everything is OK.
But if he just assumes everything will be OK, maybe one day it won't.

And if a compass is "well shielded" it won't be able to function as a compass.
It has to be able to sense small changes in the earth's magnetic field.

Thanks,, but what about rebar, manhole covers etc, those do not have a current running through them?  
Disregard that comment, I misread the brackets

I always say sources of metal as it's easier for others to determine than which actual metal is a potential problem and which isn't, for example, aren't manhole covers iron?

Bashy Posted at 7-26 18:11
Thanks,, but what about rebar, manhole covers etc, those do not have a current running through them?
Disregard that comment, I misread the brackets

I did advise that at the very minimum he should be turning on the drone away from the car and wait until the gimbal has finished its dance

Bashy Posted at 7-26 18:11
Thanks,, but what about rebar, manhole covers etc, those do not have a current running through them?
Disregard that comment, I misread the brackets

Steel or iron.
Steel is just an alloy of iron

Copper, zinc, lead, aluminium, silver, gold or just about any other metal you're likely to encounter won't have any effect on the compass.

True, but I find it better to say metal, least that way bases are covered, a small example would be copper, you said its OK, but on the other hand you said its not, cables with a live current, another would be aluminium, many car skins are built from it, yet there's plenty of steel and copper in there also.

Anyhoo, thanks for the replies, one is going back to bed now, 3:30am here still

Current thru cables produce a magnetic field, like Labroides already said. Large Iron objects also have a big influence on the drone's compass.

I remember one day, trying to take off from a rock in iceland with my mavic (1) pro. I got a warming to calibrate the compass. Took it from the rock to calibrate. Warming gone. Calibrate. Put it back on the rock to take off, as that was an open place between a lot of greenery. Compass calibration error again. Had to had lunch. I guess the was a lot of Iron ore in that rock.

Hello there. Good day and thank you for reaching out. All metal objects and structures can give out magnetic interference and might affect your flying experience and please take time to check your compass arrow if it is pointing on the right heading as well. Have a safe and a happy flying always.

DJI Stephen Posted at 7-26 20:00
Hello there. Good day and thank you for reaching out. All metal objects and structures can give out magnetic interference and might affect your flying experience and please take time to check your compass arrow if it is pointing on the right heading as well. Have a safe and a happy flying always.

All metal objects and structures can give out magnetic interference and might affect your flying experience

Who tells you this nonsense?
It's bad when DJI is a source of misinformation.

Almost no metals will cause magnetic interference.
But iron and steel are the most commonly encountered metals and they do create magnetic interference.

JohnDG Posted at 7-26 19:23
Current thru cables produce a magnetic field, like Labroides already said. Large Iron objects also have a big influence on the drone's compass.

I remember one day, trying to take off from a rock in iceland with my mavic (1) pro. I got a warming to calibrate the compass. Took it from the rock to calibrate. Warming gone. Calibrate. Put it back on the rock to take off, as that was an open place between a lot of greenery. Compass calibration error again. Had to had lunch. I guess the was a lot of Iron ore in that rock.

I got a warming to calibrate the compass. Took it from the rock to calibrate. Warming gone. Calibrate.
DJI's warning is very badly worded.
There is no need to recalibrate a perfectly working compass when it warns you of magnetic interference nearby.
The compass is fine and recalibrating it won't change a thing.
Just power off, move the drone and start again.

Labroides Posted at 7-26 21:27
I got a warming to calibrate the compass. Took it from the rock to calibrate. Warming gone. Calibrate.
DJI's warning is very badly worded.
There is no need to recalibrate a perfectly working compass when it warns you of magnetic interference nearby.

I realised it when I put it back on the rock and got the same calibration error. Took it off the rock and hand lauched it. No problem flying it.

As I was on a cliff with all around bushes, I had only a small space to fly the drone out and get the picture. Didn't want to have problems with the compass. And I was quite a noob at that time. I bought the mavic pro (1st edition) a month before going to iceland for the first time.

I started from sunroof many times with mini 2 and i've noticed zero problems with this kind of starting.

Bashy Posted at 7-26 18:11
Thanks,, but what about rebar, manhole covers etc, those do not have a current running through them?  
Disregard that comment, I misread the brackets

Some sports fields in Australia have concrete cricket pitches with synthetic turf on top. Even it will play-up with the IMU.

donmusico Posted at 7-27 04:35
I started from sunroof many times with mini 2 and i've noticed zero problems with this kind of starting.
https://youtu.be/rmmmNIk0PI4

Just because nothing has happened does not mean it won't happen.

Take it from me, my laguna had a large sunroof, larger than many other cars, plus some of the car was plastic, wings etc, when I took off the 1st time from the glass, the drone had a fit, had the row of trees been 20m closer, I would have taken the p4p home I a carrier bag.

If you start the drone away from the car and wait till the gimbal has stopped doing its dance of its peoples then you minimise the risk because its set itself up for the magnetic field already.

Labroides may remember my incident, it's in the phantom section, will try to find it...

I can't find it, weird....

I agree with many others in this thread, I personally wouldn't recommend launching around anything that could affect the drone's compass.  I'm guessing DJI's software has gotten better at dealing with sudden magnetic deviations better than it did in the past, but I personally wouldn't trust it.  

Dose everyone understand the compass is in your iPhone.  So all that metal could actually affect the compass.
I would never do that and having all that metal around.  Yes you may get away with it but there had been crashes.
I never takeoff near any metal.
Doug

Donut Michigan Posted at 7-29 11:15
Dose everyone understand the compass is in your iPhone.  So all that metal could actually affect the compass.
I would never do that and having all that metal around.  Yes you may get away with it but there had been crashes.
I never takeoff near any metal.

It has nothing to do with the compass in the phone, it is to do with the compass in the aircraft.

Donut Michigan Posted at 7-29 11:15
Dose everyone understand the compass is in your iPhone.  So all that metal could actually affect the compass.
I would never do that and having all that metal around.  Yes you may get away with it but there had been crashes.
I never takeoff near any metal.

An error of the phone compass would only affect the attitude/map display and not the actual flight control. Only the magnetic sensor in the drone controls the drone flight.

Geebax Posted at 7-29 16:44
It has nothing to do with the compass in the phone, it is to do with the compass in the aircraft.

Oh Really. Then when I removed my iPhone and rotated the phone only the map rotated with just rotated the phone only and not the controller. I don’t think there is a compass in the controller .

Donut Michigan Posted at 7-30 20:49
Oh Really. Then when I removed my iPhone and rotated the phone only the map rotated with just rotated the phone only and not the controller. I don’t think there is a compass in the controller .

Whatever you are trying to say, the meaning isn't coming through.
What you are describing is teh compass in your phone being affected by the magnetic parts of teh controller.
By turning the phone, you've put the phone's compass sensor further away from the problem.

But that only affects the display of the orientation indicator.
It has no effect at all on the drone's compass or how the drone flies.

I take off and land very often from the roof of my car - so far without any problems!  The Mini2 has even automatically balanced a start from a sloping surface.

ozoffi Posted at 7-31 02:39
I take off and land very often from the roof of my car - so far without any problems!  The Mini2 has even automatically balanced a start from a sloping surface.

Just be aware is all, it can easily happen, just because it hasn't yet does not mean it won't, I took off from my sunroof once, just the once, will never do it again, was a very scary moment, I had very little control, I was told after the event that I should have put it into ATTI mode, that way I could have controlled it, hindsight an all that..

Bashy Posted at 8-2 04:55
Just be aware is all, it can easily happen, just because it hasn't yet does not mean it won't, I took off from my sunroof once, just the once, will never do it again, was a very scary moment, I had very little control, I was told after the event that I should have put it into ATTI mode, that way I could have controlled it, hindsight an all that..

Something unexpected can always happen ... Only the metal of the car is hardly the cause.  Several things come together at once.  I can even control my Mini 2 from inside my car - certainly less than 100 meters, but it works perfectly in the immediate vicinity!  But I had problems outdoors on a hill, where there was a cell phone mast nearby (NO car, NO power lines, etc. nearby).

Good luck

ozoffi Posted at 8-2 22:02
Something unexpected can always happen ... Only the metal of the car is hardly the cause.  Several things come together at once.  I can even control my Mini 2 from inside my car - certainly less than 100 meters, but it works perfectly in the immediate vicinity!  But I had problems outdoors on a hill, where there was a cell phone mast nearby (NO car, NO power lines, etc. nearby).

What you are describing has nothing to do with the compass.   Metal in the car can cause major compass errors.   Had a tailgate on Chevy pickup that would make any compass in 20 feet stand up and take notice.

Then no navigation system should work on the mobile phone IN or directly next to the car ... but it does it perfectly (direction display of the compass). But maybe we have different vehicles here in Europe than in the USA
But yes, you are right - metal in sufficient amounts can affect a compass.

ozoffi Posted at 8-3 22:18
Then no navigation system should work on the mobile phone IN or directly next to the car ... but it does it perfectly (direction display of the compass). But maybe we have different vehicles here in Europe than in the USA
But yes, you are right - metal in sufficient amounts can affect a compass.

I might be wrong but i think there is a difference between the UAV compass and your phones. Please do not
look at it that way,  you will find time when you will come a cropper, and I am one of those that say "told ya so!" ;)

Of course you should never say never. But as I wrote, I have already successfully taken off and landed from / on my car roof and bonnet several times. Both when I was sitting in the car and when I was standing next to it or 5 meters away.
Since I don't plan to change my car or drone in the near future, I shouldn't have any problems.
I haven't had any problem in the immediate vicinity of power lines either. Only a cell phone mast disrupted the radio connection. But a change of location was enough - 100m further there were no more problems.
It was even more frightening when the APP froze ... I could still control the Mini 2, but the homecoming function was inactive ... So I had to fly on sight, which is not so easy when it quais in the sky with backlight becomes invisible and you don't have a video image to see where it is ...
But that was obviously a cell phone problem. After a restart, the APP worked perfectly again - now I always restart the mobile phone (Android) before using the mobile phone as a drone screen so that something like this doesn't happen to me again.
Perhaps it also makes a difference whether you use the automatic (take-off / landing button) or do it manually (I always take off and land manually)?

ozoffi Posted at 8-4 04:30
Of course you should never say never. But as I wrote, I have already successfully taken off and landed from / on my car roof and bonnet several times. Both when I was sitting in the car and when I was standing next to it or 5 meters away.
Since I don't plan to change my car or drone in the near future, I shouldn't have any problems.
I haven't had any problem in the immediate vicinity of power lines either. Only a cell phone mast disrupted the radio connection. But a change of location was enough - 100m further there were no more problems.

But as I wrote, I have already successfully taken off and landed from / on my car roof and bonnet several times. Both when I was sitting in the car and when I was standing next to it or 5 meters away.
Why even mention where you were standing?
If there's a problem, it's with the compass in your drone.
Where you were is irrelevant.

I haven't had any problem in the immediate vicinity of power lines either. Only a cell phone mast disrupted the radio connection. But a change of location was enough - 100m further there were no more problems.
No-one has ever had problems with power lines or cell towers ... unless they crashed into them/

It was even more frightening when the APP froze ... I could still control the Mini 2, but the homecoming function was inactive
That makes no sense.
If you have control signal, the RTH functiion will work just as joystick control does.

Perhaps it also makes a difference whether you use the automatic (take-off / landing button) or do it manually (I always take off and land manually)?
No .. that's as irrelevant as where you stand.

Labroides Posted at 8-4 04:52
But as I wrote, I have already successfully taken off and landed from / on my car roof and bonnet several times. Both when I was sitting in the car and when I was standing next to it or 5 meters away.
Why even mention where you were standing?
If there's a problem, it's with the compass in your drone.

You can only say so much, i learnt the hard way, I did just the once, I don't know, perhaps the Mini2 is more forgiving in his situation, but we know it will happen sometime, just a shame folks don't listen...

Interesting that some have problems in all sorts of situations as you can read here in the forum, others never ...

What's that saying?, "never say never"
My experience was with the P4P, like i said, the mini 2 could well be more forgiving. Good luck with it, I'm not saying don't do it, just be mindful that you are taking off of a steel object that has copper wires in the roof too

Unless of course, there could be a perfect reason as to why you guys are ok, what cars do you have and the year?

I've launched from the sunroof many times.  In some cases I would have to calibrate out the car then go back in and launch through the sunroof.  But everything was fine after that.  

https://youtu.be/7bCoPoL_RhM

There must sommat about these minis that draws folks to do these things, it must be more forgiving too, just bear in mind what we've said on this thread.
Ive not fully read the manual, actually hardly any to be honest, to be truthful, 1 page lol but, I bet there is something in there somewhere about the AC and
ferrous materials, if not, I would be very surprised, actually, I'm gonna have a wee browse now, BRB...

Well, what can I say, its a bit contradictory, page 40 says (see image)
In one breath they say to stay away from magnetic sources and in the next breath
they fly with caution from a vehicle, which to me means nothing about ferrous materials,

its more about safety, in my opinion, of which is crazy talk...

What say you, Labroides?
1
2

I have a question about the combo charging box (3 batteries) for the Mini2. It says at the back at input 3 volts, 5 volts and 12 volts.
Does that mean that you can connect another USB-C power supply to it, which brings more power and then e.g. to charge 1 or 3 batteries faster?

Would this power supply:

45W USB-C Netzteil Ladegerät HP A045R031L + Frei Ladekabel

Thank you for answer.

djiuser_uoKhxjK1H0JU Posted at 8-9 15:14
I have a question about the combo charging box (3 batteries) for the Mini2. It says at the back at input 3 volts, 5 volts and 12 volts.
Does that mean that you can connect another USB-C power supply to it, which brings more power and then e.g. to charge 1 or 3 batteries faster?

HI, it would, but not at a great speed as looking on Amazon.de, it is only 12v/2a = 24 watts, you want one that's 1 port @ 12v/3a=36w, it doesn't matter if they are more than one port, you need it to be able to
use the full 12v/3a from 1 port, more ports used it will share that power so charging speed will slow down,
such as this one

• Input: AC 110-230 V ~ 50/60 Hz, 1.5A Max
• Type C1 output: 5V3A; 9V3A; 12V3A; 15V3A; 20V3.25A; (65 W max)
• Type C2 output: 5V3A; 9V3A; 12V3A; 15V3A; 20V3.25A; (65 W max)
• USB output: 5V3A; 9V3A; 4.5V5A; 5V4.5A; (30W max)
• Type C1 + Type C2 Power: 45W + 18W (65 W max)
• Type C1 + USB output: 45W + 18W (65 W max)
• Type C2 + USB output: 15W + 15W (30W max)
• Type C1 + Type C2 + USB total power: 45W + 10W + 10W (65 W max)
• 
  

There are other chargers out there but to be fair, this is one of the very few i could find that
has 12v/3a from a single USB-C port

NOTE: I make no guarantees or endorse using 3rd party chargers, but as DJI do not actually do a fast
charger for their product that can actually fast charge, we are left with no alternative but to look for a
3rd party device or stick with snail pace.

PS. having said that, this is the very unit I will be buying myself after you let me know how it goes ;)
seriously though, its on my DJI wanted list, so it is earmarked to be bought, I just have other items
needing priority and there is no hurry has my Note 20 Ultra 5G charger works just the same as the one
above, just that its only a single port

Good luck

Bashy Posted at 8-9 17:28
HI, it would, but not at a great speed as looking on Amazon.de, it is only 12v/2a = 24 watts, you want one that's 1 port @ 12v/3a=36w, it doesn't matter if they are more than one port, you need it to be able to
use the full 12v/3a from 1 port, more ports used it will share that power so charging speed will slow down,
such as this one

Thanks @Bashy for your good answer.

So you mean, I can safely connect this HP charger to the DJI charging box and charge the battery with it. That's enough for me if I can charge just one battery a little faster than with the DJI 18 watt charger. Do not all 3 have to be loaded at the same time.

Is the charger you found from Amazon now better than mine, which I wrote here?

I just wanted to know whether I can connect this HP charger that I discovered to the DJI charging box without destroying the charging box.

You don't have to charge all three at the same time, that's up to you, but if you use 2 ports, like USB C and USB, USB C will be fast and USB will be normal at 18w.

The charger I found is far better and won't damage it

Taking off shouldn't be a problem.  It's the landing.  Almost damaged the DJI FPV drone when it landed improperly and bounced on the roof, then the hood, and luckily on the sidewalk where no one was and no property.  100% I had no control over that happening other than forcing a take-off during the bounces which could've resulted in problems.  I was in goggle mode too.  It worked fine a few times then got complacent.

AntDX316 Posted at 8-11 01:07
Taking off shouldn't be a problem.  It's the landing.  Almost damaged the DJI FPV drone when it landed improperly and bounced on the roof, then the hood, and luckily on the sidewalk where no one was and no property.  100% I had no control over that happening other than forcing a take-off during the bounces which could've resulted in problems.  I was in goggle mode too.  It worked fine a few times then got complacent.

No its not fine, but Labroids and I have pointed this out to the point of boredom setting in so I will leave you all to make your own choices, you have the correct information, what you do it with it is up to you.

As for landing on the roof, dot it slowly, although I think with the mini2 you don't get much choice in auto landing, but if you cancel that and wait until forced landing, you can then slow that down with the left stick up, in my case that is, just take it very slow and it shouldn't bounce...