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Battery low rth feature

Discussion in 'Phantom 2 Vision Discussion' started by general01, Aug 13, 2014.

  1. general01

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    After I updated the phantom and app to the latest versions I got the low battery rth mode to kick in

    It worked fine the first time

    Ok I calibrate the battery per dji's instructions and during the second flight after doing that the low batt rth message didn't show

    As I was landing it (almost ready to touch down) I lost power and it went down a bit faster then I expected but nothing was damaged

    I am concerned it may be a software glitch
    Has anyone else had this happen with the latest firmware???
     
  2. general01

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    Bump anyone
    I hope I ain't the only one with this issue
     
  3. ProfessorStein

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    So... to try to replicate your issue, you're saying flying out once until it comes back due to low battery, and then fly out a second time and wait to see if it returns again?

    Or do you think the battery calibration caused the problem?

    I haven't had any issues like you describe, but I don't generally wait for low battery warning to kick in.

    It's a feature that might save you in a pinch, but I certainly wouldn't rely on it as my standard landing mechanism.
     
  4. ProfessorStein

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  5. John Shaw

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    This requires more testing but here is my experience...
    On my first test of 3.06, after other testing, it was showing it was within 2 minutes of the first warning so I hovered about 50 feet away from home at a few feet off the ground. I waited until the warning triggered and popped up the dialog box. I selected the return and it climbed slowly and returned overhead. I took over manually because I was very close to some trees and a light pole. I landed manually. (I have this on a youtube video)
    On a subsequent flight I had the Phantom back at the home point, hovering at a few feet off the ground and it was showing about a minute remaining so I waited. To the best of my recollection, it gave a warning but I know the dialog box did not pop up. I was surprised and momentarily confused but went ahead and completed a manual landing. I concluded this wasn't a problem figuring that the Phantom was smart enough to know it was already home so an RTH would be pointless. Just my experience and assumptions - needs to be confirmed.
     
  6. general01

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    This is almost how it behaved(I had no control on its movements in GPS mode after the rth kicked in)

    I thought as it hovered over the home point that maybe I can over ride it so I switched to atti mode and regained control

    What gets me is that it didn't show during the second flight after calibrating the battery(it just lost power as I was landing it at the end of the flight with no loss of directional control)
     
  7. general01

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    See my other post but its almost exactly how mine did

    Odd thing is the second time I was near the take off spot when I was landing and the batt meter read 15% something I didn't like letting the battery get down to(always landed at the first low batt warning)
     
  8. J.James

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    I was not aware there was any way to calibrate the battery on the smart battery's. How is that done?
     
  9. ProfessorStein

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    Maybe he means a full deep cycle... almost depleating the battery and then charging it fully? That used to "calibrate" batteries. But it's actually NOT something you're supposed to do with LiPos.
     
  10. J.James

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    Ok i thought thats what it might of been. Tho I know that normally lipos dont like to be run down below a certain volts per cell I have noticed the dji smart battery's cant be run down that low any way even when they are at 0% or close to it they are still over the limit. So its more basically showing you that you have 100% of useable charge when its at 100% and they also will not let you run the down to tho point they cant be recharged Unless the internal charge circuit craps out then they cut the cell out and it will never take a full charge again or work right after. yet they will still show by the leds that it took a full charge and even say is 100% charged but not really be and So I dont ever fly unless I plug it in to the naza and look to make sure it took the full 5200mah and that all 3 cells voltages are correct. That way I dont have to worry about thinking I have about 20 minutes of flying time only to have the smart battery be a smart *** and try to go in to auto crash mode after only flying for 5 minutes.
     
  11. general01

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    Its recommended by laptop companies to do it once a month to properly calibrate the battery meter(I know as I work on computers)never had a problem doing said procedure
    I have done it on them at the recommended time point and never had a problem

    The only time I ever had a issue with a lipo battery was when I had a laptop get stored improperly(the battery was fully charged before it was stored) due to that the owner had to buy a new battery for it

    I have skipped doing a few times on some devices and the meter would show the battery was charged only to have it crap out 30mins later

    Yes it may be not recommended but at least I know the meter isn't showing the wrong level in flight

    I do notice some time when I fly fast at times the battery does get a bit warm after the flight(normal?)

    As far as the low batt warning it worked as it should today during the flight(I had to override it though as the phantom almost flew I to a tree(doh))
     
  12. general01

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    Even dji recommends what I did see below
    (Source the dji phantom vision manual)

    It’s recommended to charge and discharge the battery thoroughly once every 20 charge/discharge cycles. Users should discharge the battery until there is less than 8% power left or until the battery can no longer be turned on. Refer to the DJI VISION App for an exact readout of the battery percentage level. You should then fully recharge the battery to maximum capacity. This power cycling procedure will ensure the battery is working at its optimal level.
     
  13. pencilcoil

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    I have experienced the same thing. Would have been damaged if it was any higher. See my earlier post viewtopic.php?f=7&t=22719 interestingly nobody else has experienced it.......... Yet!
     
  14. general01

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    I just had it do the rth with a "low battery" at the same percentage as listed in the thread and as it came back to me(300 feet away 300 up) and the speed caught me off guard (I was like wtf) it was going almost 20mph

    I also have noticed the the GPS rth position doesn't hold(i took off 10 feet away from where I was at it almost landed next to me and not where I had took off from)
    I had to override the rth landing
    I also would start to land around 15-16% to be safe at further distances