Crash caused by battery failsafe problem?

I have been struggling with getting meaningful warnings about low battery. Thus, I have installed a small panel with 3 LEDs; one for arming connected to pin A7, one for GPS connected to A6 and the third for low battery connected to A5 (I wanted to use a LED instead of a beeper).

In MP, I set the LED_MODE to 11 and turned on the Battery failsafe with action to land. (see pictures).




When testing this a few days back, I kept the hex at a low altitude (to avoid fatal crashes). I have also installed a FrSky battery monitor so I can see the voltage on the radio.

When I was getting close to the low voltage alarm I had set on the FrSky, I suddenly saw the arm led on the hex blinking. Probably because I had reached the low voltage set in MP. After a split second, the hex leaned over about 45 degrees and crashed into some chairs. Fortunately only some propellers and the GPS pole was damaged.

If someone could provide some help on the 2 issues below, I would be very grateful.

  1. I have tried to analyse the log, but I have to little knowledge about it. I can see in line 2908 that I get ERR 6 and that MODE is set to Land in line 2907 (the line before ??).
    But why does the hex lean over and crash?
    I have attached the log below. Any help on looking at it would be very much appreciated.
  2. Regarding the low voltage alarm, I would just want to get an alarm at a specified voltage so I can land manually. And why does not the LED connected to A5 light up when I reach the limit? 

2014-11-24 08-12-24.log

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    • You can say that again! This is also my experience. The FrSky telemetry however, does a perfect job.

      • everything is not accurate unless you have a 3 lbs dmm meter hooked up to it lol there all meant to give alittle bit of safety but ive learned you never trust electronics after all man created it..its bound to fail.. look at windows and nasa lol

  • What Frsky TX do you have?  How is your battery failsafe configured.   You should have the TX voltage alarm set at a value above the one in MP so that you have time to react before the failsafe kicks in.  IMO it should be a last resort, not something to use on a routine basis to land you out of trouble.

    • Thanks for your answer. However, it does not answer my questions.

      I have the Taranis TX, X8R RX and the FLVSS LiPo sensor. This works like a dream and I can sett alarms at any level I want.

      However, initially I wanted to use the functions in the APM to get warnings at a level I want. 

      And..... I want to find out why it crashed instead of landing as it should have done.

      • were you outside or testing inside? with a good unobstructed view of the sky?

        the land mode uses gps if it can to land without drifting and this WILL cause problems in an environment where there are a lot of gps signal reflections (inside, between buildings, trees..)

        crashed my tricopter because of this and now I rely on voltage alarm set to beep ~1min before the battery is critical

        • I was outside and I also waited until I had a GPS lock before arming. So I don't think that's the problem.

          How have you set up your voltage alarm?

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