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Battery error - some tests

Discussion in 'Pro/Adv Discussion' started by Damir Odak, Apr 1, 2016.

  1. Damir Odak

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    Mar 28, 2016
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    Few days ago I got "battery error" warning. Of course, I wasn't relaxed. Accident could make my life miserable. If it falls on someone's head or car from 300 ft, it could ruin his and consequently my life. Fortunately, this time "battery error" just issued brief red flag, disappearing afterward, but the damage to confidence I have in my Phantom.

    I did SOP (standard operating procedure) of trying to provoke the situation again. I did several flights with two batteries. By doing that I learned quite a few things about the batteries that could be useful to share.

    First and foremost, quick degradation of performance. Climb rate is 5m/s at 95% and 3m/s at 30%. On top of flying slower, battery attrition is faster in second half. So, I am now convinced that craft should be operated accordingly, using second half of "fuel" only for return and approach.

    Other thing I noticed is that batteries finish their "tour of duty" with significant temperature difference (all other things, including initial readings being equal). Non-Gremlin one ended on 42C°, while G-one ended on 46 (tested twice) on practically the same mission. G-infested battery was fully exhausted in 2 minutes less flight-time, ending test on 18% instead of intended 22%. Test flight sheet attached.

    My conclusion is that they shouldn't be treated as "batteries". Instead, each should be conisdered as Mrs./Mr. Battery . Battery 1, Battery 2... and that pilot should consider which Battery is in when making decisions.

    After noticing its relative weakness, I “exercised” Battery 1 as instructed – down to 8% and full recharge. I got next day interesting results: 17 minutes flight time and 48 C°. So two minutes less and two degrees more. Not exactly an improvement.

    I did some readings on forums trying to find witnesses knowing something about the problem. I found them. Both kinds – reassuring and not so reassuring.

    Those in first group noticed brief red flag "battery error", which appeared once, quickly disappeared and they continued normal operation happily ever after. Others got same brief red flag, screen turned black and white and they have never seen their Phantom 3 again.

    Question I wanted to ask is: "Are there any experiences indicating connection between the two – meaning whether there are any experiences (personal or heard from someone) that "disappearing" "battery error" red flag was noticed any time before case of catastrophic battery failure?"




    Phantom 3 battery test flight sheet
    (unfortunately, I can't insert table)
    March 30, 2016
    Temperature 16 C°
    Dew point 6 C°
    Wind light, NW
    QNH 1016

    Test missions:
    Repeated at 90%, 50% and 30% batt.
    Climb from 5 ft to 350 ft QFE
    circling and maintaning 2 min
    descend to 5 ft QFE
    hovering untill new cycle

    Battery 1 2
    Lifetime 100% 100%
    Charged times 16 6
    Initial charge 93% 94%
    Initial V 17 17,06
    Initial bat. temp C° 23 24

    RoC m/s
    90% 4,9 5
    50% 3,7 3,6
    30% 3,2 3,1

    Final charge 19% 22%
    Final V 14,8 14,8
    Final Bat Temp C° 46 42
    Flight time min 19 21
     
    #1 Damir Odak, Apr 1, 2016
    Last edited: Apr 2, 2016