Another I2 falling out of the sky

[The Editor]

OK, can we stop there please with the name calling etc.

I'm getting bored with explaining this which I have done many many times previously on the forum and it has been discussed ad nauseum previously over various threads. However, I will explain it again for those that missed it or are just too lazy to use the search function on the forum.....

Zero percent indicated on the app IS NOT zero volts. It never has been, it never will be. If it was your lipos would be destroyed beyond use.
The same way as your mobile/cell phone shows zero and turns off the phone, it is NOT at zero volts but has an LVC (low voltage cut-off) which is there to protect the battery.
DJI 'intelligent' packs are no different and have an LVC of just over 3 volts per cell to protect the pack. By running them down to zero (percent) to calibrate the packs will not destroy them because they will remain above 3.1v per cell and shut down to protect them.
This brings me onto my next point (which I have explained numerous times).
The percentage display is not accurate and relies on an algorithm to give an approximation of depleted charge state.
There is no correlation (or certainly no accurate one) between pack/cell voltage and percentage - it varies.
It is for this reason that ALL packs (yes even Inspire 2 ones) that rely on a fuel gauge/percentage display will need recalibration from time to time to teach the logic what is 'Full' and what is 'Empty'. These end points change with age of pack since the internal resistance of the cells increase over time/use as well as the capacity of the pack diminishes and the logic must be 'taught' where these end points have shifted.
So to summarise.
0% is not zero volts
An LVC protects the packs
Percentage displays are not accurate (percentage is arbitary whereas voltage is absolute)

Learn to fly by pack voltage rather than percentage and you will have no issues.
Anyone regularly flying their packs down to low indicated percentage levels is asking for trouble since you are approaching the plateau of Lipo discharge where it will just drop like a stone - this will cause your LVC to kick in (maybe before auto land level) and your aircraft can simply drop like a rock.

 

[Zip-Rush]

What don't you understand about 12% is too low period, full stop, end of story.

Again, pilot error, not a malfunction and totally preventable.

Sent from my SAMSUNG-SM-G891A using InspirePilots mobile app

Tell me... would you expect DJI to pay for you pilot error?

 

[Donnie Frank]

You shouldn't just assume that I am (again) and idiot beginner because I did drain my battery periodically and am not a biginner What is it with you guys judging everyone in the blog? Who are you anyway.

Who said anything about you being an idiot? Ironically, the only person to called you an idiot was you. What part of "With all due respect" did you not get? I was simply imparting information in a respectful manner. Reread what I wrote.

 

[The Editor]

This thread is getting near closure!
If you want to take a pop at each other take it to PM.

That way I don't have to read it!

 

[Donnie Frank]

OK, can we stop there please with the name calling etc.

I'm getting bored with explaining this which I have done many many times previously on the forum and it has been discussed ad nauseum previously over various threads. However, I will explain it again for those that missed it or are just too lazy to use the search function on the forum.....

Zero percent indicated on the app IS NOT zero volts. It never has been, it never will be. If it was your lipos would be destroyed beyond use.
The same way as your mobile/cell phone shows zero and turns off the phone, it is NOT at zero volts but has an LVC (low voltage cut-off) which is there to protect the battery.
DJI 'intelligent' packs are no different and have an LVC of just over 3 volts per cell to protect the pack. By running them down to zero (percent) to calibrate the packs will not destroy them because they will remain above 3.1v per cell and shut down to protect them.
This brings me onto my next point (which I have explained numerous times).
The percentage display is not accurate and relies on an algorithm to give an approximation of depleted charge state.
There is no correlation (or certainly no accurate one) between pack/cell voltage and percentage - it varies.
It is for this reason that ALL packs (yes even Inspire 2 ones) that rely on a fuel gauge/percentage display will need recalibration from time to time to teach the logic what is 'Full' and what is 'Empty'. These end points change with age of pack since the internal resistance of the cells increase over time/use as well as the capacity of the pack diminishes and the logic must be 'taught' where these end points have shifted.
So to summarise.
0% is not zero volts
An LVC protects the packs
Percentage displays are not accurate (percentage is arbitary whereas voltage is absolute)

Learn to fly by pack voltage rather than percentage and you will have no issues.
Anyone regularly flying their packs down to low indicated percentage levels is asking for trouble since you are approaching the plateau of Lipo discharge where it will just drop like a stone - this will cause your LVC to kick in (maybe before auto land level) and your aircraft can simply drop like a rock.

Sorry about the name calling. When someone "comes at me," I get defensive. My bad.

And for the record (I can't speak for everyone), I absolutely know that "0% battery left" is NOT zero volts. If someone assumed that I meant "zero volts," that was a highly erroneous assumption.

For further clarification, unless one goes through the trouble of dead shorting a TB47's posts or connecting a light bulb or motor or some other resistance device directly to the battery OTHER than the Inspire, there's no way to bring the battery to zero volts. I just assumed everyone in this forum knows this.

 

[Zip-Rush]

Who said anything about you being an idiot? What part of "With all due respect" did you not get? I was simply imparting information in a respectful manner. Reread what I wrote.

You said "if you would have discharge.... like I do" You did not say it but certainly imply it. Your comment was condescending for sure.

 

[NickU]

OK, from experience this afteroon, here's possibly a little more light on how this might have happened to the guy in the vid' -> Low battery, auto gear/land and refusal to land.

 

[Donnie Frank]

You said "if you would have discharge.... like I do" You did not say it but certainly imply it. Your comment was condescending for sure.

Well...I didn't mean to imply you were an idiot. I was just trying to suggest you "do what I do" and you shouldn't have those problems. That's all.

 

[Donnie Frank]

Lol... I like that 16 times is what your base for "a lot" of charges...

<sigh>...seriously? Please tell me you're not being serious here. Is it even possible to misread 2 paragraphs as horrible as you have??? Here...I'll bubble the math to the surface via a fun word problem:

16 flights to zero X charge-to-zero every TEN fights = ????????

A: 160 charges.

I consider 160 charges across 4 batteries a decent number. YMMV.

when you use as many batteries in as many devices as I do, I'll listen to the engineers over some idiot Chinese greedy people....

I would be happy to put my battery collection against yours any day. Cameras, audio equipment, wireless devices, drones, RC toys, and on and on and on.... Every flavor, every capacity. I literally have batteries charging at any given time 24/7. So I'm WELL aware of how rechargeable batteries work.

You keep draining those batteries, and I'll do my thing, I've read the book, I also use many more lipo batteries than most here and have read plenty on them. Even have a friend who designs specialty batteries, so who cares what you choose to believe.

It's been brought to my attention that, perhaps, you think "0%" in the DJI Go app means "zero volts." Nothing could be further from the truth. "0%" in the DJI Go app runs the battery down to about 3.3v per cell. I just assumed you knew this. My bad. I would never run a LiPo down to zero volts.

Good day.

 

[skybandit]

Request to The Editor: Please delete everything after your post above summarizing voltage, LVC, etc. I've found this forum to be a great source of information and discussion and that's why I come here. If I want drama I'll tell my wife she looks fat in her dress. Thank you.

 

[RobH2]

These individuals will fly down to way too low percentages of battery so not unexpected.
A Lipo discharge curve is virtually flat until it finally falls off the plateau like a rock.
These inexperienced flyers are not flying by pack voltage but the totally inaccurate percentage gauge. They then cry when their new toy drops because they pushed it too hard.
In thirty years of flying RC I have never had a crash because I pushed the pack too hard/low. Before telemetry I would fly by timing and measuring how many mAh I put back in the pack. When telemetry came along, I have always flown by pack voltage.
I have crashed for other reasons but never over stretching a flight pack.

I'm a new Inspire 2 owner and am reading a lot of posts as I learn this machine. I just wanted to say that the treatment the user who started this thread has received is unprofessional and unfair. The downfall of many forums is that it turns into a place where people try to "one up" each other and denigrate each other. It serves no purpose and it's counter productive. I'm a moderator on one of the largest 3d printing forums and we don't tolerate it. What many of the users here who insulted this guy forget is that we are all inexperienced flyers until we aren't. We all have to start from zero. And any of you who won't admit that in your early days you did something silly or dumb as you learned is certainly denial.

I've also been an Industrial Designer for 38 years and will tell you that the user was smart to try to see what the limits of his machine are. Any engineer will tell you that you that you should never operate any machine without knowing it's capabilities and limits. He just wanted to know what the limits of the batteries are. Sure, doing that at head height was probably not the best decision. I might have hovered at 1' over some tall grass or low plants instead. But I too have wondered when the machine shuts off. And anyone who has ever used a device, any device that uses batteries already has a preconception that when a battery says it has 14% left, then that's 14% left. You don't throw your beer out or your cheesecake out when there is 14% left.

In thinking about this I did a test yesterday with my drone. I started it sitting in my office and ran it, monitoring the battery delta until, until it shut off. I wanted to see safely where that threshold was. I realize I didn't have the load of the motors and other components but it was a fair test. I watched anxiously as the batteries crossed 20%, 15% and under 10%. It kept running and the cells had only lost about 0.1 volts. My controller of course was barking "low battery" at me and the display on the app was doing the same.

I was surprised to see the batteries reach 1% with the batteries still were above 3.5V. One battery dropped to 0% and then in about 30-seconds the other dropped to 0%. At that time I had a popup warning that said, "land immediately or risk damaging batteries" so I immediately shut off the machine.

Again I realize I was not flying, but that performance is what we have all come to expect out of a battery, that it runs until it's nearly dead. So for a machine to just "turn off" at 12% or 14% is counter to all that we know about the devices we use every day. And it was smart of the user to try to determine at what point the machine shuts off. It was wise to do that in his back yard instead of on a job or in public. He might do it at a lower altitude next time.

I believe he also makes a few good points that call into question some of DJI's business practices. I own 5 DSLR cameras and 6 GoPro cameras. If one breaks or gets damaged, I have others to use while it's being repaired. But a $3500-$6500 machine makes it impractical for most of us to own a backup. And I guess that the vast majority of drone owners are very accomplished mechanically. It makes no sense that we can obtain or stock a few repair parts other than blades. I've been repairing electronic devices and others like tvs, toasters, washers, irons, computers and cars (to mention just a few of the 1000s of things I've tinkered on and repaired) and without exception, if you need a part for them, you can get one and try the repair yourself and at your risk of voiding the warranty. I too find it very odd that we can't buy repair parts. Losing 3-weeks of revenue and having to mail in your delicate and expensive machine becasue you can't get a replacement landing gear foot is odd. I know that's not the part he broke, I'm just making a point.

I'm always trying to keep our 3d printing forum positive and professional. Sometimes it takes retraining some younger users and informing them that criticizing, calling names, insulting and flaming another user is just not helpful. It reduces the validity and credibility of the entire site and it's just unfair and short sighted. So I appeal to everyone to be tolerant. Before flaming a user, step back and take a moment to put yourself in their place. We all have different ways of expressing ourselves and don't critisize someone for not speaking or expressing they way you would. Try never to tear someone else down and only offer constructive advice and help. If you can't post something helpful, then just sit on your hands and don't post at all.

And finally, I hope the moderators here will do a better job of not allowing negative posts to proliferate. Instead of condoning them you need to condemn them. This site has a lot of very experienced and smart users with a lot of years of experience. It is a fantastic resource for those of us entering the Inspire world. It takes a lot of work to keep a forum strong and professional and it's the moderators who have that power and responsibility. Our actions as moderators will define whether our forums become the premier "go to" forum or if it's is overlooked because it has become another one of those ridiculous ones where the kids cuss at each other page after page.

So to the user who started the post, I appreciate your having taken the time. It gave me some things to consider and test and alerted me to a few of DJI's practices that I was unaware of. That's valuable information. Just don't test failure times on your batteries at 6'. Try 6" instead....lol.... Take care...

 

[pulsar747n]

These individuals will fly down to way too low percentages of battery so not unexpected.
A Lipo discharge curve is virtually flat until it finally falls off the plateau like a rock.
These inexperienced flyers are not flying by pack voltage but the totally inaccurate percentage gauge. They then cry when their new toy drops because they pushed it too hard.
In thirty years of flying RC I have never had a crash because I pushed the pack too hard/low. Before telemetry I would fly by timing and measuring how many mAh I put back in the pack. When telemetry came along, I have always flown by pack voltage.
I have crashed for other reasons but never over stretching a flight pack.

Could you explain how you fly by pack voltage? What voltages do you use for warning, time to fly back, voltage to safely land and the lowest safe voltage to fly?
Does it varies from battery pack to battery pack?
Thanks

 

[bluelight.support]

I'm a moderator on one of the largest 3d printing forums

so your the guy to help design add-ons for the Inspire 2 are you!!!!!!

 

[Ftolino]

So far what I've read is about inspire 1 batteries an discharging them down till they shut off . Isn't this a I2 discussion these are different batteries not required to reset like a I1 . I see some bad advice going off an app fuel gauge. More falling out of the sky to come

 

[DamesNY]

was temperature mentioned in that long video? I didn't notice it mentioned, but maybe I missed it. If it was 70 degree F or 15 F would make a world of difference despite the i2 heating systems.

 

[Gregp2017]

Hello everyone, from what I have read above, the only sensible think to do when flying an expensive drone like the I2 is use some common sense. Don't rely on the % of batt power left shown in the app, make sure your drone is close by and near the ground before the batteries get dangerous low. There is not a snow ball chance in hell, I'm will have my drone along ways out when the battery is getting low.......I don't see any point in pushing my luck.