TL;DR: Powering the RC, in flight, via the microUSB may lead to problems.
(If that's where you stop reading, a reply will show it; there are many details, please curb your enthusiasm :-)

 Lucky Me Lucky me, I'm about to leave for a visit to the AZ/UT region. I'll have six Mavic Air batteries; three are spanking new. But I'm afraid the RC power will poop out and put a stop to the fun at some point while I still have batteries ready to fly.
The microUSB port on the side of my RC is unused, because I connect my iPad Mini to the RC using the USB-A port between the grips (big shout-out to MavMount!). I believe that's common. :: The plot thickens :: I had heard that in this situation, you can plug an external power source into the microUSB port during flight; this should theoretically bypass the internal battery and power the RC. With a beefy external battery, I could fly all day without a care about the RC power!

So I gave it a try; simultaneously, I wanted to flight-test the three new MA batteries before hitting the road. And while the RC itself had a full charge, this setup actually seemed to work! The charge-indicator LEDs on the RC ran the charging sequence (1,2,3,4,repeat), but otherwise everything seemed normal. I kept the bird low, just buzzing around the yard and across my suburban street, maybe 120' (40m) distant.

But after a minute or two, the DJI GO 4 screen went dark except for a terrifying notice: Aircraft disconnected

 !! YIKES !! 
I do not like this. PANIC! It was only across the street, and I quickly realized that despite the black screen, the RC still worked! ("How can this be? What does 'disconnected' even mean, if the bird is. Not. Actually. Disconnected?!?") Flying back was easy-peasy, but I was queasy :-/ indeed. Without telemetry, flying blind is not likely to end well if the bird is essentially invisible, even if it's within LOS. Had this happened out over some arroyo or above a distant butte, I'd have had to rely 100% on RTH (stay on-topic, folks). My faith in failsafe systems is more fervent regarding the 'fail' than the 'safe'. [As it happens, the bird was actually under a tree; RTH would have made it—briefly—a wood chopper. I'm glad I took control before that kicked in!]

The Mavic Air occasionally has video lag, but if you trust the bird and pay attention, it's bearable. And I've had Strong Aircraft Interference warnings ("Go home now, Gomer!"). But a disconnect—the total loss of video and telemetry—is quite frightening, at least to a novice like myself. Even if it isn't really disconnected. (WTF?)

The battery in the M.A. wasn't exhausted, but I switched it out anyway (with the second of the new MA batteries). With the RC still plugged into that gassed-up 20,000maH power-pack, I reconnected and went for another flight. Again, I stayed low and just cruised around until the battery was 30%. There were no issues, so I began a shakedown cruise with the final new battery.

And it happened again: Aircraft disconnected Yikes again!! This time the bird was maybe 50' (16m) away, maybe 70° of elevation. I was done for the day & landed. Dalwhinney time.

 After the Adrenaline 
Today, I flew three similar flights with exactly the same setup, except no external power whatsoever. In particular, I flew two of the three new batteries, and one that has a few furlongs on it. Everything went swimmingly; no disconnects. YAY! [Except this nagging question: was the issue really external power?]

For those who will ask: all the firmware and software (bird, controller, DJI GO4, batteries, you name it) are current; in fact these were the first flights of any kind after the March 21 firmware update [Nag], and I'd applied it to all six batteries in one sitting. I had about 17 GPS satellites, and no compass warnings.

For the curious, this point-of-view in Google Maps shows the takeoff point (the driveway partially obscured by 2 green trash bins and a pickup) and the first point of disconnect across the street (±30" {0.6m} altitude, 5 feet from the open fence section where an American flag is visible, between the tree trunks there). There are no overhead powerlines, no obstructions, no utility boxes, a short distance, a neighborhood I've flown a lot with never an issue, and BTW greenery isn't greenery in March. When I replay the flight in DJI GO 4, it simply terminates at the point of disconnect (duh).

 Baseless Theories and Idle Speculation 
Maybe some confusion between the power-pack and the RC caused the disconnects. The power-pack is itself a smart device; maybe it's chattering data into that port and not just power, though I'd say doing so would be bad design. Cross-talk on that port would probably be 100% protocol errors, so there shouldn't be an issue, but shouldn't isn't couldn't.

Or perhaps there was a momentary disconnect-connect on that microUSB plug, sending the system down the rabbit hole. I was using a cable that I use all the time for my phone, but I noticed later that its microUSB plug doesn't softly click into place on the RC like it should (and like other cables do). But neither does it just fall out; once in, it tends to stay put. I didn't think to snug it in at any point, but I am a tad dubious that it was flickering power during these flights. I had the rig on a lanyard around my neck, and during this time I was bending and squatting and moving around with the power pack in my hip pocket; a plug so loose that it would flicker the connection should have just fallen out at some point. It didn't. Nor do the disconnects correlate with some significant movement on my part.

Or maybe it's just a bad idea, you know? Applying power to the RC whilst in flight might be stupid. As handy as it might be, it might also be just stupid. If doing this doesn't cut the battery out of the circuit entirely, then it's definitely stupid. I've been stupid before. But at this point I'm not going to risk disconnects! Nope. Whatever happened, it happened only on those three (mostly short duration) flights with external power to the RC; never before or (haha, three relatively short flights) since.

I can live within the power allotted to me by the RC; if the bird is grounded because the RC can't fly her, she's grounded until it can. So be it.

--Li'l Bertie

PS: Or maybe it was something else entirely. [Nag]

A whole separate thread, probably. Let's not hijack this topic; I'll start another if someone has insights I should know. Or PM me, if that's possible here.
For those who will suggest log files: I thought the flight records might hold a clue, so I used DJI Assistant 2 to pull them from the bird. On discovering they're binaries, I acquired DatCon 3.2.0 to extract the data within. While ExtractDJI appears to function, DatCon rejects its output files. OK, so I used DJI Assistant 2 to pull just individual flights, bypassing ExtractDJI. DatCon will accept these, and it spins like a ballerina while creating the CSV, TXT, KML, everything you could hope for. But when it's done, they're all empty files, zero bytes in size. Oh, great. Either DatCon has trouble with DAT files from the Mavic Air, or I missed some critical step. I'm guessing the former, since I work carefully, and DAT files seem to be pretty fluid in their structure. YMMV, mine sure does.

I have similar issues with phone disconnects while remote stays in control. I am not using an external power supply while flying, and I am fly Mavic Pro, not Air.

See my thread https://forum.dji.com/thread-138893-1-1.html

some related posts:

https://forum.dji.com/forum.php? ... 1&extra=#pid1242007
https://forum.dji.com/thread-138893-1-1.html
https://forum.dji.com/forum.php?mod=viewthread&tid=139205 entry 16#
https://forum.dji.com/thread-139254-1-1.html

However I suspect latest firmware I have no proof of it, because I did not fly in wintertime. Before wintertime no problems at all.
Still no solution. :-(

Please keep me informed.

You have 6 batteries flying time will be approximately 90/100 minutes, your RC will last over 2 hours don’t see what the problem is...

after 4 batteries in sport mode - i have around 40% rc battery remaining; after 4 batteries in gps mode i have around 15% rc remaining. Maybe the sweet spot is 5 a/c batteries per RC full charge, and keep the other for spare?

Bekaru MP UAV Posted at 2018-3-25 06:49
after 4 batteries in sport mode - i have around 40% rc battery remaining; after 4 batteries in gps mode i have around 15% rc remaining. Maybe the sweet spot is 5 a/c batteries per RC full charge, and keep the other for spare?

You can charge the RC with any USB/OTG cable just like charging a phone in your car although it will take longer as most phone blocks only put out 2-5Ma.

Thanks for the pointers, @chiplifter; I'll follow up on them later today!
Meanwhile, to those inclined to answer a question that wasn't asked, or offer tutorials on the obvious, well ... carry on, I guess. I downvote replies of that sort, though, since they just decrease the signal-to-noise ratio.

Li'l Bertie Posted at 2018-3-25 10:03
Thanks for the pointers, @chiplifter; I'll follow up on them later today!
Meanwhile, to those inclined to answer a question that wasn't asked, or offer tutorials on the obvious, well ... carry on, I guess. I downvote replies of that sort, though, since they just decrease the signal-to-noise ratio.

Your ignorance knows no bounds, you ask a long drawn out question more akin to someone with attention deficit disorder, you laud the one person who gives you all the information about Mavic Pro, yet your long drawn out question was regarding MavAir, information regarding transmission which is WiFi in MavAir and Ocusync in Mavic Pro , so totally different to what your flying.

You then have the audacity to downvote all those who gave you useful information which you obviously couldn’t work out for yourself , like simple math of dividing time of six batteries by the amount of time your RC lasts for.

Most people around here give up their time to help you and if some of it is pragmatic so be it, it’s not given for any reason only to help, so quit with the insults and be thankful that they’re are a few here who bothered to try to help.

Most didn’t, I expect this is as a result of the long winded question.

hallmark007 Posted at 2018-3-25 05:12
You have 6 batteries flying time will be approximately 90/100 minutes, your RC will last over 2 hours don’t see what the problem is...

You are absolutely right, he could fly quite a few more before RC gets critical.

hallmark007 Posted at 2018-3-25 11:53
Your ignorance knows no bounds, you ask a long drawn out question more akin to someone with attention deficit disorder, you laud the one person who gives you all the information about Mavic Pro, yet your long drawn out question was regarding MavAir, information regarding transmission which is WiFi in MavAir and Ocusync in Mavic Pro , so totally different to what your flying.

You then have the audacity to downvote all those who gave you useful information which you obviously couldn’t work out for yourself , like simple math of dividing time of six batteries by the amount of time your RC lasts for.

And you are right again!

First: If someone less disdainful of a newcomer has something to add, I'll be monitoring the thread and will gratefully accept whatever insights you may have.
Meanwhile: When I hit unexpected disconnects, I thought I'd write something that would cover the obvious questions (external power, firmware state, conditions, secondary issues, etc.) and avoid the endless clarifications that often prelude the actually helpful info.

Of course, that takes words, and who wants to read when you can just jerk your knee or sumthin'? Gently suggesting that useless input on the matter is, in fact, useless, I get vilified (as does @chiplifter for his on-topic, if possibly misguided as-if-that-matters, comment and links) because it's disrespectful? How disrespectful is it to tell me I can charge my RC at will? Now that's an insult, not to mention off-topic, but I'll bear it with a simple downvote, no other comment. That tells the commenter that the input was not helpful. In similar circumstances, I'd say to myself, "Yeah, he's right, my comment didn't remotely address his situation" and either move on or get back on-topic. In any event, a downvote is not a blanket denial of anyone's expertise or goodwill; it's just a notation that a particular comment was not helpful in the context in which it was made. No biggie. Is this hard to understand? Apparently so. You guys.

I have to say, the astronomical communities that I've been part of for decades are universally friendly to newcomers, understand the limitations of their knowledge, and also respect the integrity of a thread (not to mention its author) by staying on-topic. Perhaps I've stumbled into a less gracious subculture here. I have indeed wondered; I have seen bullying and condescension in various threads, but didn't pay much attention. My mistake.

I'll note, again, that only one member so far has attempted to even tangentially address the central question of the unexplained disconnects, and his comments, too, were derided. A bonus insult from the intelligentsia! What a great thing you guys have going! Keep it up!
    "O, Keep Your Circle Tight, Boys, and Paint your Faces Blue!"
Excuse me if I just show myself out of this circle ... sumthin'.

Seriously, I am so done with the Bluefaces, and I sincerely hope they are not the norm here. If you have any information about these unexpected, unexplained, and unnerving disconnects, I am all ears. Bluefaces need not reply. (At least I recognize a couple of those cobalt visages now, so I've got that going for me! :-) )

Li'l Bertie Posted at 2018-3-25 14:37
Interesting. The astronomical communities I've been part of for many years are friendly and respect the integrity of a thread and its author. Perhaps I've entered a lesser subculture. Excuse me. I'll just let y'all go.

Down voting people who are trying to help shows how little integrity you possess , to earn respect you must first show some respect.

“A lesser subculture” again only to willing to insult.

“No one is more insufferable than he who lacks basic courtesy.”

hallmark007 Posted at 2018-3-25 14:56
Down voting people who are trying to help shows how little integrity you possess , to earn respect you must first show some respect.

“A lesser subculture” again only to willing to insult.

Sez the guy who launched on my mild request with, "Your ignorance knows no bounds,"
Your message is loud and clear, though probably not the one you intended.

Li'l Bertie Posted at 2018-3-25 14:37
First: If someone less disdainful of a newcomer has something to add, I'll be monitoring the thread and will gratefully accept whatever insights you may have.
Meanwhile: When I hit unexpected disconnects, I thought I'd write something that would cover the obvious questions (external power, firmware state, conditions, secondary issues, etc.) and avoid the endless clarifications that often prelude the actually helpful info.

“Meanwhile, to those inclined to answer a question that wasn't asked, or offer tutorials on the obvious, well ... carry on, I guess. I downvote replies of that sort, though, since they just decrease the signal-to-noise ratio.”

So this was your first response to the new community you joined, how endearing.

Your done with the Bluefaces the circle of tight boys.

“I have 6 batteries but I’m afraid the remote control will Poop”

The fact that you didn’t know that your RC has almost double the power (3 hours) of your 6 batteries , could have avoided the long diatribe of a question that followed.
It may have benefited you to just ask “ would a beefy plugged into my RC while flying effect my transmission “

So members tried to help by considering your first point would your RC poop before 6 batteries, you obviously didn’t know or why else would you pose the notion, it was pointed out in good faith that you would have no problem with lack of power .
But you chose to insult those who in good faith tried to help, 1 by being obnoxious and 2 by being dismissive of some information you didn’t know and would clearly have benefited you going forward.

You then tried to compound things with name calling of people you don’t know instead of apologizing for your ignorance and moving on, but that’s up to you.

Li'l Bertie Posted at 2018-3-25 19:03
Sez the guy who launched on my mild request with, "Your ignorance knows no bounds,"
Your message is loud and clear, though probably not the one you intended.

My message is exactly how I intended it to be, if you can’t take it don’t dish it out.

L'il Bertie???  Now that user name does not check out, Big Bertie would suit a whole lot better.

I just can't believe there are people which can be so full of them selves. Thinking they made a huge discovery and writing a testamony like there is no tomorrow, because... you think the world would love to hear talk about your revelation. I've got news for you, you are not that important.

If you would have read posts on the forum, like you said you did, you would have noticed that Hallmark, Bekaru, Quad kid and Wachtberger will be the first to reach out a helping hand to anyone in need of advice, they are a prime example of how someone gives to a community. A 'thank you for your interest, but it doesn't really address the issue' would have been enough. But no, lets dedicate a compete post full of judgemental and self-righteous confessions because... you think its interesting.

Now you might not always get the answer you were looking for, but the way you are dismissive of someone tells more about you then about them. And that will reflect on you, and the answers you will get, which will probably be none if you keep acting like the toxic self-righteous prick that you seem to be. Its ironic to see, that with your 'elitist' replies you create your own self fulfilling prophecy. You may blame yourself for derailing your own thread.

You reap what you sow,


Good luck with your future endeavours, and happy downvoting mate.
Edit: added Quadkid and Bekaru.