ALTA death spiral and crash

Discussion in 'ALTA' started by Adam Varadi, Nov 26, 2015.

  1. Adam Varadi

    Adam Varadi Member

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    Let's hope we won't find any other ALTA crashed with graupner air module or with Xt90S in the next year. Then we can be sure. :)
     
  2. Tabb Firchau

    Tabb Firchau Administrator
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    Just a note,

    This report was from Dave Thomas, Shane Colton, and the Engineering team. I just posted it. If I had done it, it would be missing all punctuation and had lots of misspellings ;)
     
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  3. Dave King

    Dave King Well-Known Member

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    Tabb

    Thanks for being as transparent as possible. A couple things that stick out to me. One is that the data logging stopped prematurely. Could you please work toward making sure that the datalogging continues until the copter has a ground speed of 0? I think its really important to have all the data. Secondly could you please design a program that us users can use to look at flights in a more friendly manner. I know that Andy has worked on bandaiding this to together that requires a converter and then GPXtools but far from ideal and I don't believe all the data can be retrieved and its not exactly the most user friendly way to do it. Having a program where you can just import the flight and see all the variables in a nice graphic and ease to use interface would be extremely helpful not only to diagnosis flights but also to check to see how the Alta is working.
     
  4. Tabb Firchau

    Tabb Firchau Administrator
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    Copy that Dave! Thanks for the feedback.

    Data logging stopping prematurely is a tough one to solve in instances like this where a brownout is occuring. If you dont have sufficient voltage to power the

    Noted on the data visualization tool, we will try and get something ready.
     
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  5. Andreas Riem

    Andreas Riem Member

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    What about the Hercules Antispark. Was it not implemented onto the Alta as well?
     
  6. Adam Varadi

    Adam Varadi Member

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    No, only the XT90S was used woth the graupner air module. (The air module was only on one of the battery inputs)
     
  7. Andreas Riem

    Andreas Riem Member

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    Great investigation by Freefly, but unfortunately, with eye on the Graupner Electric Air Module without a clear conclusion.

    @Tabb: Did you also tried to reproduce the failure by "wrong/ unlucky" plugging of the XT90s? On one hand Graupner writes that you have to ensure, that minus is plugged before plus - on the other hand, you can buy the module with XT60 directly from Graupner.
     
  8. Steve Maller

    Steve Maller UAV Grief Counselor

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    "The observations indicate a transient voltage or current overload occurred at some point during boot or operation."

    This is as close to a smoking gun as I think we're going to see, but clearly Freefly's recommendation is to not use the Graupner Electric Air Module.

    It can't be said enough that the ALTA is a fully-integrated platform, with only a few systems that can be extended (RC radio receivers, FPV, etc.). The modifications that Adam did to his ALTA, including changing the power leads with anti-sparks and adding the Graupner module may or may not have caused the crash. But IMHO ALTA owners should not be doing these kinds of mods. Other platforms may be perfectly suited to this kind of thing, but not the ALTA.
     
  9. Dejan Mugosa

    Dejan Mugosa Member

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    @Tabb

    If you would check a little and follow the graupner air module you would know that it is assembled correctly .
    Since they have a misreading on 6s and up the graupner made this change with installation so that the voltage is displayed correctly.
    This is modification by graupner for users that use 6s and don't use the battery balancers to get the correct reading off the battery cell input.
    So this is assembeled with graupner instructions and it is explained in graupner pdf file. Not something adam did on its own.
    Othervise the voltage is 1V less than it should be since the negative and positive are not measured correctly.

    I am not here to judge but fact is a fact.
    Graupner air module is something that could not be blamed. As for xt90 and ec5. I realy don't see the diference in how they operate.
    Maybe I missed something here. But the polarity also makes no sence. And I never saw that post in the manual about polarity or you managed to download a realy old manual from graupenr.com.

    I can look up to grapner update for 6s without cell balancer conection update pdf file.


    But I loved how you professionally did the update and tried your best at finding why it has failed.
     
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  10. Adam Varadi

    Adam Varadi Member

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    Just curious. How is it possible to connect the negative terminal first? EC5 connect the same time. XT90 connect the same time. Only if you use individual connector, than you can connect the negative first.
    Or am I wrong?

    (And one small note. The Graupner module was connected to only 1 battery...)
     
  11. Rolf Ableiter

    Rolf Ableiter Active Member

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    there is a difference between XT90s and EC5:
    the antispark in XT90s
     
  12. Steve Maller

    Steve Maller UAV Grief Counselor

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    By using individual bullet connectors instead of EC5 or XT-types.
    Like these: http://bhpho.to/1kITprG
    I think you were doing this incorrectly.
     
  13. James Adkins

    James Adkins Member

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    Am I hearing it is not recommended to use the EC5 connectors that come standard on the Alta for battery connection also?
     
  14. Rolf Ableiter

    Rolf Ableiter Active Member

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    @james: no - only when using the graupner air module for telemetry

    the best way to use an ALTA is to use it as it is :)
     
  15. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Dejan:
    The current manual on graupner.de is version 1.3:
    http://www.graupner.de/mediaroot/files/33620_ELECTRIC_AIR_MODUL_WEB_V1.3_EN.pdf

    On pages 2 and 3 it specifically says:
    WARNING: When connecting the battery to the module it is mandatory to observe the following​
    sequence, otherwise the module or receiver can be destroyed: battery negative → battery positive​
    → balancer connector. To disconnect the reverse order: balancer connector → battery positive​
    → battery negative. The battery negative terminal must always be connected fi rst and disconnected​
    last!​

    On page: http://www.graupner.de/en/products/...38e6d1624498/33620/product.aspx?tab=downloads
    it shows that the manual was last revise on 13.08.2012.

    It sounds like you have a more recent version of the manual. Could you please post it?

    The Air Module uses shunt resistors to measure current (it measures the voltage drop across the resistors and calculates the current base on that):

    Current measurement with shunt resistors 2x 0.2 mOhm (5 W) parallel = 0.1 mOhm​
    See http://www.graupner.de/en/products/a60b6f0a-69bf-4cc7-a98a-38e6d1624498/33620/product.aspx

    There are no images on the graupner.de site, but Graupner's US distributor has some:
    http://www.openhobby.com/front/productdetail.php?productcode=001000000000000904&sort=

    Note that the Electric Air Module is shown with bullet connectors only -- not with XT60/XT90/EC5 -- so I presume this is because of the "connect the negative before the positive" requirement (which you could not do with the XT or EC connectors).

    It's a very curious requirement, though. It means that you have to use bullet connectors on the LiPo's -- or have to have a pigtail adapter between the LiPo and the Electric Air Module.

    I don't understand how the Electric Air Module could create a voltage spike, other than perhaps if it was destroyed by failing to observe the negative-before-positive requirement and the spike is a result of the destruction of the Electric Air Module.

    However, I know guys at FF (especially Shane) know what they're talking about.


    Thanks
    Andy
     
  16. Gary Haynes

    Gary Haynes Administrator
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    Perhaps in the RC Aircraft world at some point they used individual connectors rather than paired together as in the EC5 series?
     
  17. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Good point, Gary. It's just ignorance on my part. But that's never held me back before.... :rolleyes:
    Andy.
     
  18. Adam Varadi

    Adam Varadi Member

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    So as I understand, it's not recommended to use the ALTA with the EC5 connectors that came with it? Need to be replace to simple bullet connectors, or it can crash? Doesn't seem very assuring...

    By the way the graupner air module was only on 1 battery, the other one was connected directly to the ALTA.
    I'm not an engineer, but can't really see how is it possible that the air module could crashed it...
    Or you think on one battery the air module died, and the other battery didn't like how it was connected?

    I will test the air module when I get it back, but I don't think there will be anything wrong with it...


    I understand that, but I meant the difference between the connection. Both of them connect at the same time.
     
  19. Adam Varadi

    Adam Varadi Member

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    So the stock EC5 is incorrect too?
     
  20. Rolf Ableiter

    Rolf Ableiter Active Member

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    what's so complicated?

    it is the graupner module wich needs an individual connection NOT the ALTA...
    and yes - if you want to use this module you have to change to bullet connectors if you want to use it correctly.

    all my problems i ever had was because of antispark and a Jeti current sensor (wich ist inserted like the graupner module). after i inserted it to my system with herkules II (my first cinestar 2012) herkules II burned while connecting.
    at this time no one believed that this was the reason but it was the only thing i changed before the ESC burned. It was inserted correctly (with bullet connectors). After kopterworx changed the herkules II i didn't use the sensor anymore and never had any problems (with this copter).
    i really don't know if there is a relation between using 8 or 6 ESC instead of only one (like it is in many RC planes and helicopters).
    i would be happy to know more about this.

    There is a reason why i don't want to use antisparks and current sensors. And there is a reason why i never would change anything at the ALTA. in case of emergency there is nothing to blame than the ALTA itself. That's what i learned in 5 years doing this job.
     

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