Lost my M2 Pro with DH- weird speed limit descend

[cmunozs]

Hi all!
Sorry if this has been discussed but I could not find any info about this specific issue.

I have been flying my Mavic 2 Pro for a few years now, with the hack installed. I have used the hack several times doing this very same thing and for the time ever, this has happened to me. I was flying my drone around 2.3KM in a straight line up while I was standing. I had 31% of battery left, which is usually enough to come back down at that altitude, but I must admit I normally do not come down with 30%, but 40% when flying this high. And trust me, I have done it many times. The thing is, per some reason I started to descend the drone and I noticed my speed was limited to 3m/s. Normal descent speed is around 8.4m/s (meters per second), since I changed that with the hack. Long story short, I was able to descend until I was a 150 meters from the ground, with 0% battery left when the dron lost power while in the air and fell into some trees. I might be able to recover it.

Question is: does anyone know why this could happen? Is there anything am I missing here? I know I am pushing the drone for what his purpose was intended for, but In this case, I do not see why this happened due to the hack itself.
It is a very specific question to all of you that have a drone with a modified firmware on it, I guess.
Thanks!

 

[Rchawks]

I'm sorry to hear about you crash. I hope you'll be able to recover it ok.

 

[Conservative Nihilist]

Hi all!
Sorry if this has been discussed but I could not find any info about this specific issue.

I have been flying my Mavic 2 Pro for a few years now, with the hack installed. I have used the hack several times doing this very same thing and for the time ever, this has happened to me. I was flying my drone around 2.3KM in a straight line up while I was standing. I had 31% of battery left, which is usually enough to come back down at that altitude, but I must admit I normally do not come down with 30%, but 40% when flying this high. And trust me, I have done it many times. The thing is, per some reason I started to descend the drone and I noticed my speed was limited to 3m/s. Normal descent speed is around 8.4m/s (meters per second), since I changed that with the hack. Long story short, I was able to descend until I was a 150 meters from the ground, with 0% battery left when the dron lost power while in the air and fell into some trees. I might be able to recover it.

Question is: does anyone know why this could happen? Is there anything am I missing here? I know I am pushing the drone for what his purpose was intended for, but In this case, I do not see why this happened due to the hack itself.
It is a very specific question to all of you that have a drone with a modified firmware on it, I guess.
Thanks!

It can be baffling when a drone goes AWOL while following a path that it had flown without incident in the past. Since your Mavic 2 Pro was close to the ground when you lost signal, the "Find my Drone" feature in DJI Go4 should lead you to within 50 strides of the crash-landing site. To this day I haven't a clue why my first Mavic 1 Pro vanished into the horizon never to be seen again a year ago while out on a 9-mile round-trip Litchi waypoint mission. I can only speculate that sudden battery failure might be the culprit in that disappearance.

In my neck of the woods out in the Third World boondocks, FAA and CAA rules don't apply, and that means I can launch my Mavic 1 Pro and Mavic 2 Pro quadcopters on Litchi waypoint missions covering over 13 miles round trip, thanks to the non-DJI extra-range "hump-back" batteries I buy from Ali Express.

Starting with a few spiral-ascent test flights to generate battery durability data at 26 mph cruise speeds, I progress to sending the drones off on more daring cross-country sorties that probe the performance envelope of those batteries when smart RTH is de-selected, and all power-draining obstacle avoidance sensors fully calibrated but disabled.

Keep us updated when you finally retrieve that Mavic 2 Pro, my all-time favorite DJI drone bar none. I currently own two Mavic 2 Pros and one Mavic 2 Zoom, whose thumb-wheel zoom feature is the coolest ever feature.

 

[cmunozs]

Thanks for your words! Yeah, I have one of those "hump-back" batteries you mentioned. I have actually been using almost always with my now lost drone. This time, I was using one of the original batteries, which makes me think it was something related to a voltage issue on this original battery. It was recently charged, so it should not be bad charging, but age of the battery itself, I think.
I'll try to find the drone tomorrow during daylight (this happened while the sun was setting). I have a pretty good idea of where it is, but It would be very difficult to get it from those trees o even walk around the area. We'll see...
Of course, after this already had happened, I started to think on what else I could do to make it come down faster. I didn't try sports mode Maybe that could have helped to take the drone out of that "state".

 

[Felix le Chat]

I'm not condoning the 'pushing the altitude envelope' thing at all: I run both my Mavic 2's with D-H mods and still stick to operating in complete compliance with all aviation regulations, but that's my choice. Why have I got D-H mods installed if I'm such a stickler for the rules? Because I like to have the choice instead of being dictated to.

From an academic point of view, here's a couple of questions. Did you push your Mavic up through cloud or mist? Was there either on the way back down?

If so: there's the solution, the downward sensors may have registered cloud, fog or mist as an obstacle and slowed the descent in preparation for a landing on what the drone 'thought' was a surface directly beneath it.

 

[cmunozs]

Did you push your Mavic up through cloud or mist?

Hi! Nope. Not this time. I usually do if the clouds are not thicker than a hundred meters, but this time I had clean sky.

I have most of the obstacle sensors off during my flights. That is one thing that I made sure while on my way down. I did disable them all in case that was the cause, but no, it was not.
I have flown many time through clouds and never got that kind of problem either.

 

[sonof40]

Did your hack accomplish height restriction? If so How do I find that please?

 

[cmunozs]

Did your hack accomplish height restriction? If so How do I find that please?

Yes. I can't remember the exact steps, since I did it only once, about 2 years ago, but it is well documented in the D-H website.

 

[sonof40]

Yes. I can't remember the exact steps, since I did it only once, about 2 years ago, but it is well documented in the D-H website.

OK thanks. I'll do some research.

 

[HoozierDroneDaddy]

OK thanks. I'll do some re

Hi! Nope. Not this time. I usually do if the clouds are not thicker than a hundred meters, but this time I had clean sky.

I have most of the obstacle sensors off during my flights. That is one thing that I made sure while on my way down. I did disable them all in case that was the cause, but no, it was not.
I have flown many time through clouds and never got that kind of problem either.

Just a far out risky thing to try. A couple of years back there was a video on Youtube where an individual tested restarting the motors after shutting them down in flight. He shut them off and the drone starting falling, he restarted the motors and it recovered its flight. If you have a setup where you had something to catch it with without crashing it, you could test this theory at a limited height so if it didn't recover it would land on a soft surface. If it works, it would give you the ability to go higher shut off the motors for a limited decent, then restart at a safe height to bring it in for landing.

Keep in mind, I don't agree with what you are doing, and it is illegal here. I know your in Chile, I know it's unsafe, and may or may not be illegal there. I am only providing a slim but possible solution to your situation.

. Only pro

 

[cmunozs]

Thought about that too and I don't think it could work. If I do something like that with an almost depleted battery while flying, I don't think the software/app would let me turn the propellers back on due to low remaining battery. There would be no reason to do this if I have enough battery to come back down, so in a safe situation in terms of battery level, I would not do it either.

 

[cmunozs]

Went back and tried to retrieve the drone. No luck. Walked around the trees and literally walked on top of the bushes, but nothing. Also used my M3P to look for it on the canopy.
I wish I had a beacon of some sort that could keep working independently of the drone, so I can see it during the night time…

 

[Conservative Nihilist]

I highly recommend Firehouse strobe lights on all your drones. The strobes keep territorial birds at bay and help you orient yourself with the drone's trajectory as it flies. More importantly, if a drone makes an unscheduled landing, the strobe will keep flashing for nearly an hour, which can greatly aid in locating a downed drone.

My Mavic Pro Platinum suffered an in-flight battery failure 5 miles from home. The "Find my Drone" feature of DJI Go4 brought me to a corn farm where I stumbled about for a few minutes until those bright strobe flashes caught my eye. The drone was twenty feet from where I was standing but partially covered with tall grass, so I would never have found it were it not for that little Firehouse strobe light.

 

[cmunozs]

I will get some of those strobe you are mentioning. They seem a pretty good idea in general...

 

[Conservative Nihilist]

I just found out from another discussion in this forum that a battery retainer strap is MANDATORY for the Mavic 1 Pro and Mavic 2 Zoom/Pro family of drones. I learned for the first time from that 2020 discussion that when the Mavic 1 Pro and Mavic 2 Pro models are operated at high temperatures due to weather or extended use, the battery retention clips get hot and could then detach suddenly mid-flight.

I lost a Mavic 1 Pro two years ago that was fitted with an oversized battery and sadly just YESTERDAY, Xmas day 2024 I lost another identical drone model that is most likely as a result of the same battery ejection occurring during the drone's very first test flight that was in its 25th minute when the drone dropped like a rock due to battery ejection.

I am now hurriedly retrofitting my two Mavic 1 Pros, one Mavic Pro Platinum, two Mavic 2 Pros, and one Mavic 2 Zoom drones with velcro strips on the sides of the drone body to hold in place a velcro-secured elastic strap that I will fabricate in two different sizes, to fit the stock battery and a slightly longer strap to fit the hump-back Ali Express extra-range battery. Here is the link to the discussion about battery retention straps for these older Mavics.

Mid-Air Battery Fall Out! (Mavic Pro)

Jul 23, 2020

Has anyone else had this happen? Watch to the end... see what I have purchased... any one else bought this? Also, its pictured for the pro, whereas mine is the platinum... anyone know if it will still fit ok? Thanks guys!

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• Baq Paq Jaq
• Replies: 28
• Forum: Mavic 2 Zoom

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[Conservative Nihilist]

This looks like a nice cheap yet effective and lightweight battery strap that is affordable at two for $6 - very good drone loss preventative insurance for sure.

Battery Strap Non-Slip Black 220mm x2

Non-Slip Battery Straps Set of x2 220mm Long Heavy Duty Battery Straps with a Non-slip Coating to keep batteries and electronics securely in place

www.masterairscrew.com

 

[Conservative Nihilist]

As I continue to obsess over the phenomenon of unexpected mid-flight battery ejection by the Mavic 1 Pro and Mavic 2 Pro family of DJI drones, I spotted the simplest ever solution to secure batteries from mid-flight detachment, once again in another discussion elsewhere in this forum.

ZipTies can be synched down super tight to ensure that the drone battery does not budge before landing, while zip ties will inducer much less aerodynamic drag, and be considerably lighter than rubber or fabric bands used for the same purpose. Of course, ZipTies are NOT reusable and must be cut off after each use. That said, a Zip Tie holding the battery down has got to be the ultimate safeguard that will eliminate all battery detachment worries from the list of preflight concerns.

So, zip ties it is for me, until the cows come home, for all the Mavic Pros in my small fleet of DJI classics.

 

[cmunozs]

Now that you mentioned this, a few days before "my event", I flew my drone a few times with the original battery and the humpback from aliexpress. The aliexpress one does fit a little bit tighter than the original ones, so I usually press it against the drone pretty hard until it clicks and I've been doing this since I bought it. This might actually had an impact of how the original DJI batteries fit into the drone. I had not been using the originals much since I got the humpback one from aliexpress, so this might had deform the plastics on the drone just a enough for the original batteries to not fit properly anymore. Now, your post reminded me that I was trying to use the original batteries and per some reason, the drone did not wanted to take off. It was powering on, but it did not let me take off no matter what. It gave a message saying there was not enough power to perform a flight. I check for the voltage meters and it did say cero percent battery left. The battery was recently charged a few minutes before my attempt, so I thought for a moment it was some sort of miscommunication with the drone after being so "fresh". I really needed to get the drone in the air, so I tried another original dji battery, also recently charged and it worked.
After my flight, I tried the first battery again just to see if the problem was fixed and when I put it back on the drone, I remembered to press it hard against the body. This worked and the drone powered up normally.
So, to me, this could have been the real cause of my lost of power during flight. Per some reason, the battery is not getting tight has it should (might be due to aliexpress one or might be not), but in any case, I think a zip tie is not a bad idea to keep it from getting loose or falling down.

There are reusable zip ties. The reusable feature works well, but dies after some heavy usage. I have many of those.

 

[Conservative Nihilist]

This mention you've just made about reusable zip ties is the first time I've heard of such an invention, CMunozc, and I now know that using zip ties for my drone hobby need not create plastic waste.

It never occurred to me that the Ali Express extra range Mavic 1 and Mavic 2 Pro batteries might be capable of deforming the drone's battery retention clips whereby the stock battery might thereafter require a zip tie to ensure that the battery stays in place throughout the flight.

I committed a monumental blunder that led to the Xmas day loss of my Mavic 1 Pro, but initially decided to keep details of that avoidable error to myself because with hindsight 20-20, the fix was so simple. Right from the first use of the Ali Express extra-range battery that recently arrived in the post along with two others, I had become exasperated because one battery out of three that I ordered did not emit that audible "click" when pressed into the Mavic 1 Pro.

Rather than adding a DIY battery retainer strap right away, I tried to ensure the battery was properly attached, despite there being no confirmatory click sound by pressing hard on the battery before tugging upwards on it to ensure that it would not detach during flight. I considered the minor effort that it would take to fashion a battery retention strap, but to my lasting regret now, launched the drone without implementing that simple safety measure. On a positive note the crashed Mavic 1 Pro appears undamaged except for an obliterated camera, so repair might be an option at some point.

With my belatedly acquired wisdom kindly shared in your posts here, I have decided to suspend my drone flight operations until I have purchased re-usable or single-use zip-ties to affix before every single flight henceforth. It is educational to hear from another user of those Ali Express humpback Mavic 1 and 2 Pro batteries because I suspect those batteries are only sold to a handful of people worldwide, which means that user feedback about how those Ali Express batteries fare with extended use can be difficult to unearth online.

 

[Blue Thunder Pilot]

ZipTies can be synched down super tight

It wouldn't seem to me that zip-ties would need to be cinched down super tight to do be fit to task. Being super tight makes them harder to cut off. It's a choice and my would be for the straps.

The aliexpress one does fit a little bit tighter than the original ones, so I usually press it against the drone pretty hard

That would be a red flag for me. If it doesn't fit as slick as the factory kit, then it goes back or is binned, as appropriate.

If it were a slightly higher fit I might consider very slightly sanding/shaving some plastic to get a proper fit.

Seeing how phone's battery charge can drop quickly as its health – maximum capacity – drops, I'd be wary of third party batteries in general. Before replacing my phone's battery the charge dropped from 100% down to 50% a little faster than normal. But at some point <50% it would frequently drop to 20% instantly.

Too bad we don't know why the rate of decent was so slow compared to what you were used to.