MAVIC ZOOM - BATTERY SEPARATION IN FLIGHT - POSSIBLE DESIGN FLAW? NO FAIL-SAFE FOR BATTERY EJECTION IN FLIGHT

[Ken-Mav-Mtl]

It was suggested to me that I post my experience in this forum since the cause of the crash was known:

I have just experienced a dive into water over the weekend. Luckily I was able to retrieve my drone the next day. It's now in a bag of rice to try to wick all the moisture from the drone. Also, lucky I have Care Refresh so once I get it dried out I will evaluate the need to use that service. If it works again, my loss so far is one battery (with less than 40 cycles and the props).

By the way, if anyone knows what can happen to a drone spending the night in a fresh water pond, please let me know. If there are any tests to perform to check the airworthiness of my drone, please chime in.

I have read quite a few reports of drones simply dropping out of the sky due to loss of power when batteries had enough charge to get them down safely.

This incident is also a good reminder not to fly over people or cars where a falling drone can cause injury or damage.

In my case, the reason the drone took a dive into water was clear. The battery separated from the drone while I was descending rapidly from 90 to 60 meters. The screen gave the red warning "disconnected" and as I looked up, the drone was falling with the battery about 10 feet above and beside the falling drone.

I discussed this failure with an industrial designer and pilot with 30 years of experience. His conclusion was that this is a design flaw, as a critical non-moving part such as the power source must have a fail-safe mechanism.

I had checked my battery for any sign of swelling or abnormality before every flight and I make sure to push it down firmly to hear the clicks by the locking mechanism so there was no error on my part.

The sudden and rapid descent caused the separation. Somehow the locking mechanism failed.

From now on, I will try the following fix:
Wrap a velcro strap around the body of the Mav Zoom and add a compressible material on the top to always maintain pressure, in case the locking mechanism fails again. Perhaps someone with talent can design this and add this fail-safe to existing models that use the same design as the Mavic Zoom.

Should I upload any other info? Flilght log, video, etc.? Not sure how to do this. Any suggestions?

 

[Phantomrain.org]

It was suggested to me that I post my experience in this forum since the cause of the crash was known:

I have just experienced a dive into water over the weekend. Luckily I was able to retrieve my drone the next day. It's now in a bag of rice to try to wick all the moisture from the drone. Also, lucky I have Care Refresh so once I get it dried out I will evaluate the need to use that service. If it works again, my loss so far is one battery (with less than 40 cycles and the props).


I have read quite a few reports of drones simply dropping out of the sky due to loss of power when batteries had enough charge to get them down safely.

This incident is also a good reminder not to fly over people or cars where a falling drone can cause injury or damage.

In my case, the reason the drone took a dive into water was clear. The battery separated from the drone while I was descending rapidly from 90 to 60 meters. The screen gave the red warning "disconnected" and as I looked up, the drone was falling with the battery about 10 feet above and beside the falling drone.

I discussed this failure with an industrial designer and pilot with 30 years of experience. His conclusion was that this is a design flaw, as a critical non-moving part such as the power source must have a fail-safe mechanism.

I had checked my battery for any sign of swelling or abnormality before every flight and I make sure to push it down firmly to hear the clicks by the locking mechanism so there was no error on my part.

The sudden and rapid descent caused the separation. Somehow the locking mechanism failed.

From now on, I will try the following fix:
Wrap a velcro strap around the body of the Mav Zoom and add a compressible material on the top to always maintain pressure, in case the locking mechanism fails again. Perhaps someone with talent can design this and add this fail-safe to existing models that use the same design as the Mavic Zoom.

Should I upload any other info? Flilght log, video, etc.? Not sure how to do this. Any suggestions?

We Designed the Wet Suit for those needing to fly in the Rain , and its entire focus is on creating an air tight seal on the battery and to stop it from Popping out or moving during flight or letting water into the battery.

Here is a Picture : You can see both the battery and Power Button is protected .
And Each Battery has its own Cover and Power Button Seal.

Email me at [email protected]
and I will send out some more Info thank you.

 

[lannes]

You need to get rid of the contaminants and muddy sediment out of the drone by dunking/ washing it in distilled water (without battery) , then spray isopropyl alcohol (99%) over the circuit boards and connectors, using a soft toothbrush to remove any visible corrosion.

Unfortunately you'll need to open up the AC to do this effectively. Then let dry for a week in rice or desiccant.

If it has been a while since it got wet, you'll probably need to use care refresh.

 

[Ken-Mav-Mtl]

Hi and thanks for the reply. I am well aware of your rain suit and the fact that the battery is well sealed. It is a great solution and my hat's off to you for coming up with a weatherproof system.

Personally, I prefer to fly only in good weather so never felt the need to suit up with a wet suit.

However, a fix is needed to prevent batteries from ejecting in flight. I suggested a simple velcro strap with a compressible material over the battery to maintain contact in case the battery wants to go its own way.

 

[Phantomrain.org]

Hi and thanks for the reply. I am well aware of your rain suit and the fact that the battery is well sealed. It is a great solution and my hat's off to you for coming up with a weatherproof system.

Personally, I prefer to fly only in good weather so never felt the need to suit up with a wet suit.

However, a fix is needed to prevent batteries from ejecting in flight. I suggested a simple velcro strap with a compressible material over the battery to maintain contact in case the battery wants to go its own way.

I am not sure why you would favor a Strap, that would need to be put on and undone every time you fly and carried with you over the Battery Covers ,that are seamless and never get in your way and provide protection for the Power Button.

I would think you want something that works and stays out of the way, that is what makes the Wet Suit so nice.
No amount of swelling of the battery is going to break the adhesive seal that battery covers provide and you dont have to worry about the Strap covering the Sensors on the bottom which can be a big problem .

Phantomrain.org
Gear to fly your Drone in the Rain.
Email me at [email protected]

 

[Ken-Mav-Mtl]

Can I get the battery cover without the entire wet suit? I am only looking for a way to avoid another battery ejection.

 

[Phantomrain.org]

Can I get the battery cover without the entire wet suit? I am only looking for a way to avoid another battery ejection.

The problem with that is you might rely on the battery covers to get you thru the rain, and its not enough.
You also have the vents, sensors, and the drip off masks. I sent you a Pm with more details.

 

[Johnmcl7]

Don't use rice to dry it:

https://www.ifixit.com/Wiki/Don%27t_Put_Your_Device_in_Rice._Here%27s_Why

...

There are some accessory mounts to add a tripod screw that strap on round the battery and body of the Mavic, I think of the heavier duty cable ties would do the job as well.

 

[DanMan32]

You won't necessarily detect swelling before a flight. As you fly, the battery heats up and that's when the most swelling will occur.

The app is supposed to detect when either of the latches are disengaged before flight, but I found that if only one latch is disengaged, it isn't depressed enough to detect being unlatched.

 

[sonof40]

The problem with that is you might rely on the battery covers to get you thru the rain, and its not enough.
You also have the vents, sensors, and the drip off masks. I sent you a Pm with more details.

From what I've read here, he doesn't fly in, nor need protection from rain. How does the seal keep the battery from separating?

 

[Phantomrain.org]

From what I've read here, he doesn't fly in, nor need protection from rain. How does the seal keep the battery from separating?

Good point, The problem with straps is that they our frustrating to deal with and you have to worry about the sensors below.
The Battery covers use a 3M adhesive that seals the battery all the way around making it almost impossible to pull out unless the seal is broken.

The last thing Pilots need is another Strap to negotiate.

Here is a video showing how that works:

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[Not A Speck Of Cereal]

Straps are easy, and one just needs to use proper placement to avoid covering sensors. I would be concerned with adhesive losing it's adhesiveness over time (much quicker than velcro would wear out).

 

[Phantomrain.org]

Straps are easy, and one just needs to use proper placement to avoid covering sensors. I would be concerned with adhesive losing it's adhesiveness over time (much quicker than velcro would wear out).

That is a good point, but the 3M adhesive that we used on the Phantom 4 is going on 3 years now. The Wet Suit Focus is on how to stop your batteries from swelling and being compromised.
Batteries our expensive and protecting them just makes sense. Strapping them in when there swelling is not a good idea and yet people do it to keep using there batteries.

Phantomrain.org
Gear to fly in the rain and float on water.

 

[Not A Speck Of Cereal]

That is a good point, but the 3M adhesive that we used on the Phantom 4 is going on 3 years now. The Wet Suit Focus is on how to stop your batteries from swelling and being compromised.

I'm confused. How does the wet suit keep battery cells in the sealed plastic battery shell from swelling?

Strapping them in when there swelling is not a good idea

Why?

Chris

 

[Ken-Mav-Mtl]

I am also a bit confused about the replies posted to my thread on why the Mavic does not have a fail-safe system to keep the battery from leaving the drone in flight.

Do I understand from some of the posts that a perfectly good battery with no signs of swelling and with fewer than 40 duty cycles can just overheat, then expand to the point of popping off in mid-flight?

In my post, my only manoeuvre was to descent full stick down from 90 to 60 meters which resulted in the detachment of the battery from the drone.

If a good battery can go bad on one flight, I'll have to consider using a parachute...

 

[Phantomrain.org]

I am also a bit confused about the replies posted to my thread on why the Mavic does not have a fail-safe system to keep the battery from leaving the drone in flight.

Do I understand from some of the posts that a perfectly good battery with no signs of swelling and with fewer than 40 duty cycles can just overheat, then expand to the point of popping off in mid-flight?

In my post, my only manoeuvre was to descent full stick down from 90 to 60 meters which resulted in the detachment of the battery from the drone.

If a good battery can go bad on one flight, I'll have to consider using a parachute...

NO - What happens it is very easy to miss the fact that your battery has started to swell , so what happens is your putting in a battery that has already swelled and you were not aware of it and than it heats up and expands and pop the battery just enough to disconnect. What causes the swelling is from our tests : Moisture getting inside the power button is one of the main reasons.

 

[Ken-Mav-Mtl]

Thanks for the detailed explanation on battery swell. I know that the battery never showed any sign of swelling. I am aware of the problem with battery swell, which is why I check the battery every time I place it in the drone and every time the battery completes a charge cycle.

My crash was not caused by a battery that swelled and popped out.

I need a solution to keep the battery in its proper place while the drone is in the air.

My suggestion to use a velcro strap, properly designed so as not to cover the sensors, seems like a solution.

My other solution is to wear my Gannet Bait drop device, since it has a strong elastic band to hold the bait drop mechanism in place, which would keep the battery in place if the battery latches failed. As you know, it is designed for the Mavic 2 Zoom.

 

[Phantomrain.org]

I'm confused. How does the wet suit keep battery cells in the sealed plastic battery shell from swelling?


Why?

Chris

When we first made the battery covers we left the Power Button open , that was our mistake as we quickly found out that the battery had swollen a few days latter. , Immediately after that we added the Seal on the Power Button and that ended the battery Swelling Problem from Moisture / Rain / Snow/ Humidity.

We also found out that the Battery once it started blinking after just a little rain on the power button gave us errors such as battery can no longer connect to the drone.
Followed by it falling out of the sky .

Right under the Power Button is a a Computer chip that tells the battery what to do , once that gets compromised You have all kinds of issues : GPS / Disconnect / Battery not dis charging .
So sealing that Power Button had some benefits.

Here is the video where we learned our first lesson of the Power Button being left OPEN.

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[Not A Speck Of Cereal]

What causes the swelling is from our tests : Moisture getting inside the power button is one of the main reasons.

Main reasons?

Can you please post results from these tests? Have they been reviewed by DJI or any other peer review unaffiliated with your organization?

Because a) we've had a LOT of swollen battery posts on this forum since the release of the M2P and b) I personally cannot recall a single post that mentioned flying in the rain. (Shall we take a poll of how many posters here even fly in the rain, regardless if they've had swollen batteries o not?)

I can imagine that rain could cause a failure in the power button switch mechanism, but it makes no sense that it would somehow lead to battery cell swelling, much less a "main reason".

Chris

 

[sonof40]

A scary thought but worth considering:
Maybe try a strap with the battery unclipped to allow for expansion but remain electrically connected.