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<50% batt life to 3% instantly experiment

Discussion in 'News' started by Shazbot4, Jun 6, 2015.

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  1. Shazbot4

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    i tried this in my back yard 1 foot off the ground so i don't want any "no the inspire doesn't do that" b.s.

    i keep getting a warning to discharge the battery to less then 5% then charge up to full and discharge to 50% for storage. ok so fastest way to discharge a batt is to fly it. a lot of you may already know this but i didn't. once the battery reading hits 10% automatic shut down of everything mid flight. i did this about 1 foot off the ground and the props just stopped and that's it, try to restart the motors and the app wont allow it because of low battery.

    if there is a reading that says the battery is at 3% when a second ago it was above 50% (which didn't happen to me) then the app / software whatever shuts down the props. i know dji are doing it to save battery life but what good does it accomplish if it crashes the aircraft destroying the battery to keep the cells from being over discharged, which get destroyed as collateral damage. at 2% there is enough power to keep this thing in the air.

    im going to inform dji what this feature in the battery software is doing. we should be able to discharge a battery down to 0% in the air if we want. even if it kills the cells and a person only gets 1/4 the cycles before it's burnt it doesn't matter. there shouldn't be anything that turns off the props other then there be no power left in the cells to run the lights or transmit data. they need to remove that programming that gives the app this much ability to just decide "time to turn the props off"
     
  2. DronePilot

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    Not to be argumentative or anything but the VPS and altimeter did know you were hovering 1ft off the ground. Perhaps the behavior is different when the inspire is at altitude. Not that I disagree with you. I have wondered that myself.
     
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  3. Shazbot4

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    im not ok with propellers shutting off when the aircraft is in flight. it didn't decend down nicely from 1 foot for a soft landing on auto pilot, it dropped instantly with no warning on the pilot app.. i was hovering over the home point just in case the thing decided to do a fly away.

    my experiment proves the software will shut down the props mid flight. try and argue with the people who get the 3% battery warning and pictures of busted inspires
     
  4. Kilrah

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    Whenever the battery has a cell go below 3.1V it shuts down itself, effectively cutting all power to the aircraft.

    To me it is not an issue, it's clear and easy enough that you must NOT fly it down to zero, period. And perferably obey the default 30% margin.
     
  5. Shazbot4

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    ok kilrah since you still have your "my inspire will never crash attitude" could you just stop posting? you never add anything constructive, im going to ask the mods to take your reply down.

    people are flying above 50% battery levels then it instantly drops to 3%. there is NOTHING you can do to prevent that.
     
  6. Kilrah

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    Sorry but you're the one not understanding what you're talking about and repeatedly trolling the forums.
    The fast drop is an issue that has been reported, that I'm fully aware can happen and that I'm prepared for - but more importantly I understand the reason for it, and the point is that it has nothing to do with what you've been talking about or testing in your OP. It's due to miscalibration of the capacity meter, it's unrelated to the low voltage cutoff and you won't be able to simulate it without messing with the battery.
     
    catware, acoll123 and fei8820 like this.
  7. BroxAg

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    In
    I have also done this experiment however my out come was slightly different to yours. I have done this with 3 batteries now while doing a complete discharge and while on the back lawn have been hovering at any where between 1-3 feet agl. All 3 times I watched the message come up on the screen saying critical power, landing now and then the I1 started decent, landed gently and then killed the motors - identical to a RTH cycle. I would be fairly confident to say that if you were ever flying in extreme conditions where you had to still be in the air at 10% batt (and there's no real reason you should) then the I1 would attempt to land before just plummeting from the sky. As for a drop in batt from 50-3% well that's something I hope I never have 1st hand experience at.
     
  8. Mike Ellgood

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    You can argue any argument.. why do people get struck by lightening.. who knows its called "shit happens" fly your inspire and if, and I mean if your battery issue happens guess what..

    shit just happened
     
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  9. DCGOO

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    If you push UP stick after the auto-land sequence has started, you can hold the aircraft just off the ground, and take the battery down to 0 fairly quickly, When it gets to 0 though, it IS gonna land, heheh.
     
  10. Shazbot4

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    yeah so how many situations could cause the landing sequence not to kick in? what if your like me and just happen to be above or even close to your home point? the premise for this discussion is DJI needs to remove the apps ability to shut down the motors period!
     
  11. Kilrah

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    Again you don't understand what you're talking about.

    When it hits 10% it doesn't shutdown, it lands where it is *right now* precisely so that it's on the ground before being out of juice for good where the battery shuts down. There have been zero reports that I know of where an I1 fell out of the sky after the "3% problem", the I1 always managed to land (even if not in a desirable place).

    The only reason for it to shutdown in flight is if you "fight" the autoland for too long. I.e. a double failure of yours, firstly for ignoring the first low battery warning, then insisting when it's trying to save itself.
     
  12. The Editor

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    OK guys can we take a few things into consideration here?

    1. As far as I am aware this 'sudden drop' in battery capacity has only occurred when people start their flight with a battery that is not fully charged (usually 70% or less). To my knowledge this anomaly has never occurred when starting a flight with a 100% charged battery.
    2. Irrespective of the battery protection circuit, nearly all esc's have a low voltage cut off or LVC built into them. This is usually (but not always) set at around 3v per cell for the size pack being used. Sometimes this is programmable by the user. The result of this is, when the pack reaches 3v per cell the esc's would stop the motors - the same thing that DJI's smart battery does.
    3. The normal discharge curve of any lipo is not linear. It is fairly flat down to around 3.4v per cell and then it will drop like a rock from there. It is a well know characteristic of lipos and certainly very well observed in the RC world. The result is a sudden drop to virtually nothing once it reaches this ledge.

    What DJI are attempting to do is prevent the non RC educated owners out there from completely destroying their packs and their Inspire by building in certain safeguards. If people choose to ignore those safeguards (flying below 20% or not calibrating their batteries etc) then unfortunately there is nothing DJI can do and Inspires will fall to the ground.
    This would happen even if there were no 'smart software' in the battery and people depleted their packs to get that 'little bit extra flight time' that certain individuals seem hell bent on squeezing out of their batteries.
     
    jon b, Scotflieger and Kilrah like this.
  13. BroxAg

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    Well said mr editor! Well said. There is no safe guard for stupidity.
     
  14. Mike Ellgood

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    I have 10 batteries for my inspire..... all fully charged when I start flying.. but having a " attention deficiency disorder " so after 5 mins I'm bored and land........... had over 200 flights and never had a battery issue... now i'm bored see ya!!
     
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  15. Kilrah

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    Wow, and I thought I was bad :p
     
  16. Shazbot4

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    right so where is it written down from dji not to fly a battery unless it's at 100%?

    sounds like you guys are cool with the possibility of using a battery at anything less then 100% could cause a unrecoverable crash. personally, im not. let people be idiots and blow through 1000 dollars in batteries before they learn taking them down to zero, people need to read the instructions from the factory and then they get educated.

    im not comfortable knowing at 10% my inspire could do any number of random things beyond my control, but again, some of you guys seem to be cool with it. i think the software needs a big change personally
     
  17. BroxAg

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    And that my friend is the basis of the declaration of independence, the right to freedom of speech and the ability of humans to form their own opinions. There will always be people that agree with you and those who don't. I understand the battery limitations on my machine and how it will react when I get to a set %. Fly your machine how you see fit and if you really think it's an issue then by all means put your opinion to DJI. If you still can't find joy in your I1 then I think maybe is is time to put it on the market and find another hobby.
     
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  18. Kilrah

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    It doesn't do "a number of random things", the only thing it does is land. The rest is just you not wanting to understand that.
     
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  19. The Editor

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    You should NEVER be flying your packs down to 10%. If you were flying anything RC you would probably lose it if you were flying your packs down to those sort of levels and you would get the same behaviour from any lipo pack.
     
  20. Mark Krieger

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    I saw this exact behavior today. I took off at 61% and flew to 200 feet up and 300 feet out when I got the same critical battery message. The rig started to fall out of the sky - and FAST. I was over the water and it was all I could do to pull it back to me and keep it in the air.

    Basically it went from 61% to 3% in about 1:45.

    I landed (thankfully) and then checked the battery status. It read 35%. I was able to take it around my yard at no more than 4 feet off the ground for about another 8 or so min.

    I have about 30 hours of flight time on this and have three batteries. I've never had this happen before and I most definitely have taken off on a battery that is less than 100%.

    For now, I know this is something to avoid, and I will always fly at 100% from now on. BUT - why is this all of a sudden happening to a lot of people. I have had my rig since December and have only seen this type of critical battery drop out issue in the past few days here in the forum. Something isn't right.

    Slightly off topic, I've noticed that a few people have posted videos of this the past few days. In those videos they show the data recorder playback. In that playback there is a altitude, speed, and battery indicator directly under the top header - but I don't see that on my screen at all. I've searched all the settings and have done several searches online. I'm using the Android version, so perhaps this is only for iOS?
     
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