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Newbie Question - Go-home at low battery level

Discussion in 'Phantom 2 Discussion' started by Maverick7, Feb 2, 2015.

  1. Maverick7

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    Hi all,

    I have only flown my ph2 once - when the lights started flashing red because of low battery the ph2 immediately went into go-home mode. This happened again when flying on my 2nd extra battery.

    Is this correct as I thought only will go-home when battery is at 15% and not immediately at the first (30% flashing red lights) level?

    Thx
     
  2. QYV

    QYV

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    depends on the Phantom's settings. There is indeed a particular emergency, non-override-able auto-land battery level, but also in the Assistant software can set all sorts of options including triggers for go-home behavior at certain battery level

    Look through the Assistant software at your settings
     
  3. jason

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    My suggestion would be to go into the P2 assistant software and uncheck the Low Battery Level Go Home as one day you're going to be underneath something when that feature is triggered.

    If you don't have FPV for your craft that should be your next purchase.
     
  4. rcarlin

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    My understanding is that the level at which the battery alert is triggered is dependent upon how far from home you are.
     
  5. TeamYankee

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    That's only for the P2 vision+ model.
     
  6. rcarlin

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    How were you able to discern that?
     
  7. QYV

    QYV

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    afraid that's not accurate. it's just plain in the new firmware, Vision or non-Vision. It's an OPTIONAL setting that is disabled by default (meaning you'd have to turn it on manually) and it's not exactly a "battery alert", it's an "intelligent go-home"... the P2 knows how far it is from the home point, and it knows how much battery it has left. if you enable the option, it'll trigger go-home if it senses it barely has enough battery to reach home point.
     
  8. crash1sttime

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    Thing is any system has its foibles, take for instance a phantom that has just worked out how far from home it is and knows that a set speed it can reach the home point before its battery reaches critical, however the Phantom isn't intelligent enough to know that its flying into a head wind that has gusted to 25mph and it now needs twice the available power to reach the HP, what does it do, it flies until it works out that if it doesn't land it will fall out of the sky and so initiates an Auto Land procedure and lands itself in a river or lake.

    Moral of the story, know how long you can fly, keep the phantom in LOS and never fly to the point that either LBRTH or AL has to kick in, or you may end up kicking yourself.
     
  9. QYV

    QYV

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    which is precisely why I leave the setting disabled and manage my own battery level and when to get home :)
    I would never rely solely on a computer calculation for the reasons described above, it doesn't know the environment as well as I do.

    but DJI is trying to idiot-proof these devices because they have a LOT of idiot customers
     
  10. rcarlin

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    I concur with you guys on these points. What I was just trying to point out, is that the "battery alert" or "intelligent go-home" is not based simply on a percentage of battery level. While we cannot say exactly what the algorithm is, it we be reasonable to assume that the further away the phantom is from home-point, the sooner the "go home" will be triggered.
    Now the question I have is; if you have the "intelligent go-home" enabled, but are flying in ATTI mode, what is the behavior? Since the ATTI removed GPS from the flight control, the phaton will not know how far away it is from home-point.
     
  11. QYV

    QYV

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    just being in ATTI mode doesn't mean the Phantom doesn't still know it's GPS location or that of it's home point (and therefore where it is relative to Home)

    ATTI simply removes the "GPS-position-hold" whereby it tries to hover in place when the control sticks are idle. in ATTI the Phantom will drift with the wind. ATTI also allows 10 more degrees of lateral tilt which equates to speed, but my main point is that flipping your controller into ATTI doesn't "disable GPS" or make the Phantom forget where Home Point is

    anyway it doesn't matter if you're in GPS or ATTI, GoHome is it's own flight mode on the Phantom... so I'm assuming it just flips itself into GoHome (like we can do manually with the switch or by turning off the RC) and heads home.

    the only thing we're talking about here right now is an intelligent "trigger" for GoHome behavior based on battery level and distance from home :)
     
  12. jason

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    Don't you just love it when someone asks for help but don't respond when their questions has been answered. :p :p
     
  13. Squeal

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    my phantom is telling me not enough battery to return home when its right over my head..
    thanks.