Mavic Crash

[kmaluo]

Nope - they were wrong with their advice on earlier arcraft where they said to calibrate the compass at every new flying location. This caused more problems and flyaways because people just blindly followed those instructions without actually understanding why or the reason to calibrate.
Everyone just said "DJI told me to do it so I do it"

They've since accurately updated their compass recommendations as well as their IMU recommendation. I've had 10 flights with a factory calibrated IMU and all sensors have been green, range test was perfect, numerous RTHs were flawless. A DJI engineer has stated there are downsides to calibrating the IMU unnecessarily. I'll stick with that recommendation.

 

[The Editor]

They've since accurately updated their compass recommendations as well as their IMU recommendation. I've had 10 flights with a factory calibrated IMU and all sensors have been green, range test was perfect, numerous RTHs were flawless. A DJI engineer has stated there are downsides to calibrating the IMU unnecessarily. I'll stick with that recommendation.

Don't forget, you're not talking to R&D when you're on the phone to DJI.
There are no downsides to (correctly) calibrating the IMU - none whatsoever.
It should however be done on a cold machine.

 

[devinrhall]

Don't forget, you're not talking to R&D when you're on the phone to DJI.
There are no downsides to (correctly) calibrating the IMU - none whatsoever.
It should however be done on a cold machine.

how cold are you talking...room temperature or stick it outside when it's cooler out for a little bit


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[kmaluo]

Don't forget, you're not talking to R&D when you're on the phone to DJI. [emoji14]
There are no downsides to (correctly) calibrating the IMU - none whatsoever.
It should however be done on a cold machine.

It was an engineer directly related to the design of the Mavic who posted the recommendation, not a phone rep.

 

[The Editor]

It was an engineer directly related to the design of the Mavic who posted the recommendation, not a phone rep.

Where's the post? I'd like to discuss it!

 

[The Editor]

how cold are you talking...room temperature or stick it outside when it's cooler out for a little bit


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Having it sit outside on a cool evening for half hour (with it switched off) will be fine.
Then, as soon as it has booted, go straight to the calibration screen in the app and run the IMU calibration.
Make sure it is done on a level surface with absolutely no vibrations whatsoever. Even people walking around on the floor should be avoided.
Let it run its calibration - job done.

 

[Samm]

Where's the post? I'd like to discuss it!

The original post was on rcgroups but was reposted here:
Mavic New User Info before First Flight

 

[kmaluo]

The original post was on rcgroups but was reposted here:
Mavic New User Info before First Flight

And there's numerous discussions about it at DJI and RC Groups. My opinion is unless you can verify the IMU chip is exactly the same and confirm that it integrates into the system the same exact way, no one here should state matter of factly when to calibrate it based on past DJI drones.

 

[devinrhall]

Having it sit outside on a cool evening for half hour (with it switched off) will be fine.
Then, as soon as it has booted, go straight to the calibration screen in the app and run the IMU calibration.
Make sure it is done on a level surface with absolutely no vibrations whatsoever. Even people walking around on the floor should be avoided.
Let it run its calibration - job done.

yeah i've seen people having problems after calibrating it...honestly it probably wasn't cool enough...they said they were waiting two mins for the imu to warm up


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[The Editor]

The original post was on rcgroups but was reposted here:
Mavic New User Info before First Flight

Thank you.
It seems this individual is just trying to prevent people from losing a low temperature calibration which is easily achievable (see my post above about recommendation of calibrating on a cold aircraft)
The IMU calibration is nothing mystical or magical and is simple to perform reliably providing you follow a few simple steps.
The post omits to mention about physical shocks to the accelerometers ( crash etc or a courier who's kicked the package around) which would necessitate an IMU calibration but would not necessarily throw up an error or 'calibrate' message
I shall continue to do so.

However, if people are concerned they should always check their mod values at rest for both gyro and accelerometer before each take off.

Thanks for posting that btw.

 

[Mad_Angler1]

Thank you.
It seems this individual is just trying to prevent people from losing a low temperature calibration which is easily achievable (see my post above about recommendation of calibrating on a cold aircraft)
The IMU calibration is nothing mystical or magical and is simple to perform reliably providing you follow a few simple steps.
The post omits to mention about physical shocks to the accelerometers ( crash etc or a courier who's kicked the package around) which would necessitate an IMU calibration but would not necessarily throw up an error or 'calibrate' message
I shall continue to do so.

However, if people are concerned they should always check their mod values at rest for both gyro and accelerometer before each take off.

Thanks for posting that btw.

I got into a chat about it with Dr Turbo about this as I was recommending calibrate and my own stance is calibrate but Dr T is the man and I completely understand why he is saying what he is but as I posted in my thread I simply can not - not do it based on too many unknowns, I need a baseline and that is doing It my self under my own controlled conditions.






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[devinrhall]

Having it sit outside on a cool evening for half hour (with it switched off) will be fine.
Then, as soon as it has booted, go straight to the calibration screen in the app and run the IMU calibration.
Make sure it is done on a level surface with absolutely no vibrations whatsoever. Even people walking around on the floor should be avoided.
Let it run its calibration - job done.

if it doesn't happen to be cool outside and short of sticking it in a fridge what's a good way of calibrating the imu in that case?


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[Mad_Angler1]

Also on this stick thing

We need to see if this actually correlates to stick output or not, test it with the craft on the ground props off and you would instantly see if it's sticking or not.

Also some proper testing is needed, do both stick do it ? Changes stick modes and try again ? Reboot, firmware refresh, android vs IOS ?

This could purely be an App overlay issue not anything else


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[Mad_Angler1]

if it doesn't happen to be cool outside and short of sticking it in a fridge what's a good way of calibrating the imu in that case?


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Car aircon for a few minutes in front of the vents [emoji6]


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[msinger]

In West Virginia, it's cool outside in the morning/evening. Sit your Mavic outside for 10 minutes or so and it will be ready to calibrate.

 

[devinrhall]

In West Virginia, it's cool outside in the morning/evening. Sit your Mavic outside for 10 minutes or so and it will be ready to calibrate.

yeah it's getting real cool here...i was basically talking hypothetically but in the summer i'll just stick it in front of the air conditioner...by time i get it it will probably be snowing or close to it so the cold won't be a problem...ill toss it in the snow...jk


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[Grizz1]

He mentioned he uploaded the logs to Healthy Drones. What diagnostics can they provide?

I saw that his battery was 32 degrees F. that's cold for a battery !

 

[BD0G]

I saw that his battery was 32 degrees F. that's cold for a battery !

Correct Sir! If that value was accurate that is the lowest value that DJI indicates one should operate the Mavic Pro at. Below that temperature it is suggested to "pre-warm" the battery before flight and allow the Mavic to be powered on with props spun up but just idling for bit before attempting flight.

Operating Temperature 32° to 104° F ( 0° to 40° C )

Source: Mavic – Specs, FAQ, Tutorials and Downloads

 

[LivinLarge]

I saw that his battery was 32 degrees F. that's cold for a battery !

Where did you get that info? I looked at the Healthy Drones report and it showed 89.6 degrees F.

 

[BD0G]

Where did you get that info? I looked at the Healthy Drones report and it showed 89.6 degrees F.

I was not confirming that I observed this value, but was confirming that if the original poster @Grizz1 had observed this then yes 32 degrees was the lowest value that DJI recommends. Just wanted to clear that up and I have tagged Grizz! for comment by using the @ symbol in front of his username.