djiuser_T47JcdrwtrbD Posted at 7-17 08:54
I'm also having this issue. It is definitely not happening in version .3 but I don't want to go back and miss the sweet 50mbps. Please fix this.

what are the ambient temperatures where you are flying?

Also affected, and I tried several SD-Cards. According to the FIlesize, we are talking about 50MBit or 5.5MByte/s. That's nothing, an old cheap Class10 should do the Job.   But it happens with V10 and V30 Cards.
1st flight it stopped after 2mins. 2nd flight was not even possible to start recording, permanent "SD Readonly" warning. I cannot even format the card in the airunit.  Something is seriously wrong.
At least I never had problems with the image in the goggles, it's rock solid, and the quality is stunning.

FPVZapod Posted at 7-20 13:13
Also affected, and I tried several SD-Cards. According to the FIlesize, we are talking about 50MBit or 5.5MByte/s. That's nothing, an old cheap Class10 should do the Job.   But it happens with V10 and V30 Cards.
1st flight it stopped after 2mins. 2nd flight was not even possible to start recording, permanent "SD Readonly" warning. I cannot even format the card in the airunit.  Something is seriously wrong.
At least I never had problems with the image in the goggles, it's rock solid, and the quality is stunning.

What are your ambient temps where your at? I've used fast and slow cards on 2 different air units and haven't had one flight not recorded, my ambient temps are very low in northern UK.

DJI Thor Posted at 5-6 18:49
Hi all, if you are encountering the same slow SD card issue, please try either method below:
1. Please restore the air unit to factory settings in the Goggles;
2. Please manually stop recording after takeoff and start recording again; disable auto-recording after armed and start recording manually.

I'm using a SanDisk ultra plus and it worked, honestly, before I crashed my drone a few times. After the last update, the air unit recording was disabled, but after turning it on, it started showing the "SD slow" message. Oh, I also used the power hack to get 1200mW.

I have the same problem, and tries to track down if there is something external.

I thought it actually might be something thermal, so I remounted the air unit with lot better cooling (thermal tape to the frame), and now it doesn't even get warm on the outside.

Might still be some issue with noisy voltage. But it is 8V and ripples around 50mV p-p, spikes at 100mV p-p or so, so not perfect, but not that bad (hasn't properly measured under load though). Using the regulator on a Kakute F7 HDV. Tested a spare on the bench, which has the same characteristics.

I have crashed it a few times, including hitting wet grass and such, so it might be a hardware fault too...

Changed the SD card from a Samsung EVO to the actual recommended.

But since it seems to work, and failed at the same time as a firmware update, I won't change the air unit without having any indication that it helps.

And it still fails recording mid flight, with the "SD SLOW" error.

Running mostly low latency in 50Mbps mode.
Is there any way to get a more verbose log with error messages, so it can be possible to track down what the actual issue is, if any metrics drifts/changes during the flight?

This is ridiculous DJI. I have 2 Air Units both with the same Sandisk Extreme brand card. One works flawlessly and one locks up into recording and shows "Slow". Always something.

This almost seems like a power issue, the air unit will use slightly more power as it heats up. I have questions about the thin gauge power wires that feed the air unit, especially at lower voltages such as 7.4V. The newer firmware will likely consume a lot more CPU capacity thus consume more power. For a device that is known to draw 7W and likely peaks much higher the more you turn up the tx power, the stock power wires themselves seem questionable.

spikestabber Posted at 7-30 06:40
This almost seems like a power issue, the air unit will use slightly more power as it heats up. I have questions about the thin gauge power wires that feed the air unit, especially at lower voltages such as 7.4V. The newer firmware will likely consume a lot more CPU capacity thus consume more power. For a device that is known to draw 7W and likely peaks much higher the more you turn up the tx power, the stock power wires themselves seem questionable.

I've been running at max TX power since day one and still haven't had one slow sd card error, I run 10 6s packs back to back every time i go out.

I'm having same problem with latest firmware.  I think a previous comment was talking about power issues and that have me an idea...  I'm connected to a 9v pad on my FC.   If the air unit is drawing such high wattage, the small power cable could be a limiting factor on amps.  I'm going to resolder directly to the 4S power feed on the board or battery and at 4S voltage will draw almost half (46 percent less amps) as many amps ensuring the air unit gets all the wattage needed.  For those not knowing that relationship the math is volts x amps = watts. So if you double the voltage, you can half the amperage to maintain the same wattage.

I'll report back if I have success.

Marty

mvroeghgmail.com Posted at 7-30 09:47
I'm having same problem with latest firmware.  I think a previous comment was talking about power issues and that have me an idea...  I'm connected to a 9v pad on my FC.   If the air unit is drawing such high wattage, the small power cable could be a limiting factor on amps.  I'm going to resolder directly to the 4S power feed on the board or battery and at 4S voltage will draw almost half (46 percent less amps) as many amps ensuring the air unit gets all the wattage needed.  For those not knowing that relationship the math is volts x amps = watts. So if you double the voltage, you can half the amperage to maintain the same wattage.

I'll report back if I have success.

I wonder if thats why im getting no issues as im using a DJI specific FC that has a connector designed to connect directly to the air unit with no soldering

spikestabber Posted at 7-30 06:40
This almost seems like a power issue, the air unit will use slightly more power as it heats up. I have questions about the thin gauge power wires that feed the air unit, especially at lower voltages such as 7.4V. The newer firmware will likely consume a lot more CPU capacity thus consume more power. For a device that is known to draw 7W and likely peaks much higher the more you turn up the tx power, the stock power wires themselves seem questionable.

I have some updates regarding power, since I've been trying to isolate the issue. And I have an extra spare Air Unit, which I've saved for another build. But wanted to test.

Calling the Air Units AU1 (old and well used) and AU2 (new).

Have been running it both on 25mW and 500mW. Both gave the same error on the AU1.

Thought it might be some problem with the Air Unit, for example some moisture might have slipped in. So changed to the AU2. No difference, still problem. So switched back, so AU2 can be saved to the next build.

Have been running it from the Holybro Kakute F7 HDV which contains a 8V 2A regulator, so rebuilt the cable to take power directly from the cap on the input, since i'm running 4S. No difference, same error.

I also thought it might be a thermal issue, so I remounted the AU so that it has thermal connection via thermal tape to the frame, and better in the airflow. Now I can't even feel it getting warmer when flying. Only when I have it standing disarmed for a while.

I downgraded v01.00.04.00 just to see if the problem still was available, and in fact it was. (Using AU1 on 8V, however cooler mount). Upgraded back to v01.00.06.00

Also started using the recommended SanDisk 128G card,  providing 81.7MB/s write and 89.7MB/s read using the Blackmagic speed test. Previously I used a Samsung EVO card with write speed 47.8MB/s and read speed of 90.0MB/s.


One note is that both Air Units was bought at the same time, so might be the same batch...

I'm happy to do some more research and testing, but at this point, I have not anything more to go on except the message "SD CARD Slow" in the goggles and an encrypted  from the tool. So is there any way to get a more verbose message, since I'm lost.

I have one last theory, which I can't really test... I'm thinking if there is a mechanical issue, that it appears during high-G events, and the physical connection between the card and the board glitches. Which if it just happens sometimes, I guess it should be possible to recover from? But if so, I would at least expect a an error message not saying the "SD CARD Slow", but rather write error. And possibly trying to recover the connection and write a proper file end so what's recorded actually is valid. (might be able to open the air unit and jam a paper over the card to add extra pressure)

pengi Posted at 7-31 10:06
I have some updates regarding power, since I've been trying to isolate the issue. And I have an extra spare Air Unit, which I've saved for another build. But wanted to test.

Calling the Air Units AU1 (old and well used) and AU2 (new).

I've had the problem happen twice now on my 450 helicopter, the only aspects are 7.4V bus & mounted on the bottom in full airflow. I thought it was vibrations at first. No corrupt video thus far on my 4S quad, no regulator in between. Possible issue with sd card slot itself? I have disassembled another air unit before just to see how its constructed, there are two board halves connected by a ribbon, interestingly the SD card slot sits on the RF board, the hottest of the bunch. The boards themselves seem physically secure to the chassis, as are the ribbons properly screwed down by captive brackets. Physical issue seems less likely however all bets are off if the sd card slot is fidgety under high G's. Thermal expansion could also cause issues with the slot? Has anyone actually tested what their SD cards do under >50C heat? I know for a fact that cheaper SD cards stop working during the summer in my dash camera with the windows up, the high endurance rated ones however no issues at all.

yeah... the AU1 I mentioned in the post has been disassembled, and also replaced the thermal compound since I wanted to make sure there was no issue with moisture entering. The AU2 I want to keep in good condition

I've measured the supply to 8V, however a bit noisy for my taste (ripple of about +/- 50mV, peaks at 100mV according to my oscilloscope). Reason for using 8V supply and not directly to the batteries is for me simply because it's available as a stock cable with the flight controller.  But should be within specifications afaik.

But for now, I think i can rule out high G, since I added a piece of adhesive plastic of about 0.1mm thickness to the back of the card to get a bit extra pressure to the connector. But the error appeared anyway, and also during some smooth flight, even with quite balanced props, so shouldn't be any significant vibration.

My bets are bit error during transfer, resulting in CRC error, and then bad error handling... Just a guess though...

But what I don't like is the lack of proper error messages, and that the error log is not really accessible (there is some, that gets encrypted via the DJI assistant tool).

It is obviously not a slow SD card, it is the exact model recommended which performs quite well according to benchmark software. So just give a proper error message so it can be fixed; if I need to update the power supply, soft mount it, cool it, or report a software issue and wait for a firmware update...

So...   the problem went away after I formatted my SD card with Windows 10 as exFAT.  If I format with the Air Unit, the problem happens again.  So...  seems reproducible for me anyway and I can seemingly avoid it.  Hope this helps some others.

Marty

MartyFufkin Posted at 8-4 08:25
So...   the problem went away after I formatted my SD card with Windows 10 as exFAT.  If I format with the Air Unit, the problem happens again.  So...  seems reproducible for me anyway and I can seemingly avoid it.  Hope this helps some others.

Marty

I tried formatting in windows 10 as exFAT too and I also increased the default allocation size from 128kb to 256 it seem sd card slow errors is gone but I only flew 4 batteries.

Same situation, as soon as I start doing freestyle the card fails.

DJI Thor Posted at 4-28 00:01
Hi, just to double confirm, the Slow SD card error doesn't appear when you start recording manually with the latest firmware, right?

It does, even starting manually as soon as you fly freestyle (700mw) the card stops recording in the AU. Normal flight is ok, but hig G maneuvers no.

djiuser_T47JcdrwtrbD Posted at 8-27 10:57
I tried formatting in windows 10 as exFAT too and I also increased the default allocation size from 128kb to 256 it seem sd card slow errors is gone but I only flew 4 batteries.

Ok, so this does not solve the issue. After more flights SD card slow error started to appear again... It doesn't happen that often but happens anyway

djiuser_T47JcdrwtrbD Posted at 9-6 03:09
Ok, so this does not solve the issue. After more flights SD card slow error started to appear again... It doesn't happen that often but happens anyway

Every flight I had a "Slow card" message, but today I tried to fly slowly without strong acceleration and I haven't seen this message! I flew 5 batteries slowly and no one time I had this message. Try the same. Maybe we need to put some capacitor for air unit?

I just had the same issue after 3:29 minutes when I accelerated hard forward. Also did that at the start of the flight and a bit harder, but then everything was alright (did have more forward momentum those times).

Just started with the hobby though so in the beginning I didn't have this error (flying slow/ cruising doesn't seem to get the error), but now that I'm doing 'trying' more tricks I get a SD Card Slow error midflight.

A week ago I did sometimes have a SD Card Readonly error but that seems to be gone now after I formatted the SD card (through the goggles because couldn't do it through the Air unit).

Ambient temperature: 26 degrees
Sunny, almost no wind.

DJI settings:
firmware v01.00.06.00
50Mbps
1000mW
autotemp off
autorecord on
radio on DJI HDL protocol
using the recommended sandisk 32gb

Quad specs:Airunit
4s 1800mah tattu R-line v3 120c
geprc mark 4 hd
tmotor f7 hd
tmotor pacer p60a esc
tmotor pacer p2208 2450kv
1000uf capacitor
Betaflight 4.2.2

pengi Posted at 8-1 07:49
yeah... the AU1 I mentioned in the post has been disassembled, and also replaced the thermal compound since I wanted to make sure there was no issue with moisture entering. The AU2 I want to keep in good condition

I've measured the supply to 8V, however a bit noisy for my taste (ripple of about +/- 50mV, peaks at 100mV according to my oscilloscope). Reason for using 8V supply and not directly to the batteries is for me simply because it's available as a stock cable with the flight controller.  But should be within specifications afaik.

Dear DJI Administrator,
pengi, the poster of my replied post did some serious engineering work regarding this issue, so please forward his findings to your engineers because it would surely help them to fix this problem so many of us have. Thanks in advance!

MindRIderFPV Posted at 8-31 07:27
It does, even starting manually as soon as you fly freestyle (700mw) the card stops recording in the AU. Normal flight is ok, but hig G maneuvers no.

I have the exact same problem. Fly slow - its fine. Do a powerloop or sharp turns - slow SD card error occurs. DJI, whats the plan here?

had my first experience of the sd card slow today, i had the hglrc zeus flight controller and and 60A forward ESC to try so i swapped out my iflight succex-D in my XL5 to the hglrc stack, everything else exactly the same, and BOOM 50%+ of my flights I was getting the sd card slow, looks like the problem is stack specific as ive had 2 builds both using the succex-d and not had a single sd card slow in months of flying them, first day on the hglrc stack and right from the get go problems.

Can people who are having SD card slow problems post what FC and ESC they are using

Bezik Posted at 9-18 04:55
Can people who are having SD card slow problems post what FC and ESC they are using

I'm using iflight succex-d hd stack it comes with 45a esc

djiuser_T47JcdrwtrbD Posted at 9-18 08:09
I'm using iflight succex-d hd stack it comes with 45a esc

and your getting slow sd card errors with the succex-d stack? kinda throws my theory out the window

Bezik Posted at 9-18 08:32
and your getting slow sd card errors with the succex-d stack? kinda throws my theory out the window

Yes, it's ok if I fly slowly and I get nice 7+ min video. As soon as I start punching throttle I get SD card slow error almost every time. Occasionally it's ok also when doing freestyle and I get  full flight recording but thats maybe 4 out of 10 batteries

spikestabber Posted at 7-30 06:40
This almost seems like a power issue, the air unit will use slightly more power as it heats up. I have questions about the thin gauge power wires that feed the air unit, especially at lower voltages such as 7.4V. The newer firmware will likely consume a lot more CPU capacity thus consume more power. For a device that is known to draw 7W and likely peaks much higher the more you turn up the tx power, the stock power wires themselves seem questionable.

Its fine because for wire size only amperage matters in heat production. Using 2S would give less than 1.5 amps for 10w and 1.5 amps is permissible even on tiny wires. Similarly modern phones charge 15W+ over usb wires using higher voltage (9+).

To someone who offered if its smaybe a mechanical thing related to sd case:
I did try to bend sd card holder, sd card was barely moving on its own (when you push it to come out), so it was 2x tighter in there,- didn't help at all.

I am having this issue on 1.0.600. anyone else still having problems?

Adding another account of this happening. Had my fpv system since December of 2019 and taken probably 200 recording via the air unit with no problem. 64gig Sandisk U3 card. Overall probably 5-10 hard crashes on it. Up until today it’s been fine and now no matter what I do it will record for a max of 30-40 seconds and then report a slow sd card. Hopefully there is a fix soon

I have figured out problem with SLOW SD it is protocol switch back to sbus_baud_fast = off  in betaflight and change setting in goggles to normal protocol

problem came back after couple  flights now have 2 of the 3 units I have not recording

kenp61 Posted at 10-24 08:27
problem came back after couple  flights now have 2 of the 3 units I have not recording

Did you format the sd card again (through the goggles), after having transferred the files from the air unit to the computer?
For now that seems to work for me, after each time I transfer files. Haven't had a slow sd card error in a long time. It's not ideal though, but better then errors. Don't know if it would work for you, let me know if it does or doesn't.
(Ambient temp. is colder now 15 degrees. Still using sbus_baud_fast = on and automatic recording.)

now 3 of 4 not working slow sd only 1 still working only 8 flights so far I covered  sd slot and usb maybe dirt or sand from crashes?

changes my thoughts on Air unit might only get caddex vista in future I build a lot of quads hope DJI is listening

DJI called me from overseas about my  4 air units there is no real fix for now just have to use goggles to record they are working on hopeful software update fix no time line hopeful near future

Hi to all,
You can try this workaround:
1. Format the card on Windows 10 with Full format feature, using 256k as default allocation. If is not working, try to increase the default to 512k.
Command used for Windows in order to use basic Format is:
a) press in Windows the Windows+R ...the command prompt will appear
b) write command: format X: (the X is the letter of your Card, be careful !!) /fs:exfat /A:256k
c) press Enter after you ensured that the letter of your card is correct, as it will format entirely that partition !

Drink 10 coffees...the process will take a while...
If the card is OK, at the end you will get a Successful Format message.
Do not reformat it in the unit ! will change the allocation units and all was for nothing.

Try to see if the error message for slow card disappeared.
Also pay attention at heat...some memory cards change parameters when they heat up...Sandisk is one of them...I use on summer Kingston Canvas React A1, no issues so far...with Sandisk were a few until reformat it...It seems Sandisk is more sensitive to heat and voltage...and drops a lot of speed on random writing.

Hope this helps a few...not all, as the issues can be different from one to another....
PS. Amazon seems to be full with Fake cards...try to purchase it from verified dealer!

Best regards.

So DJI, half a year has passed since this issue was reported (in this thread). I think we all deserve a statement/fix considering the premium price we all paid for your FPV system. Thanks.

airhax Posted at 10-31 08:39
So DJI, half a year has passed since this issue was reported (in this thread). I think we all deserve a statement/fix considering the premium price we all paid for your FPV system. Thanks.

Exactly What the **** is going on here. I've had 10 different DJI Air Units since this SLOW SD bs has started with an update. It happens on every single Air Unit at one point or another. Once day I can fly 5 batteries and they works as they should. The next day I get SLOW SD errors every flight.