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Battery alert/problem led to hasty landing + damage

Discussion in 'Phantom 2 Vision + Discussion' started by Serpent, Jan 2, 2015.

  1. Serpent

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    After around 100 flights across 4 batteries..
    I took my bird up when the battery was around 55% for a planned short (few minute) flight over a cliff face.
    Just as i got off the ground and about 10-15 meters out over the cliff the battery alert on the Mobile app came on and the battery showed around 5% charge left. I was quite scared and wasn't sure if the bird was going to drop out of the sky (over a very steep cliff) or not.
    I hastily brought it back home. What i noticed was the bird was loosing about .5m/second in altitude on it's own (with sticks centered) and second if i did increase the thrust it was only gaining about .5m/second in height. It was quite disconcerting and i was unable to take time to find a good landing spot. It landed on a rock which was slightly angled and although landed okay, it keeled over as the propellers were slowing down and scratched the body of the drone and the two props at the front (camera side).
    After changing both props and battery I then tried for another flight. Just as it was about to lift off, one of the (changed) propellers flew off (literally) into the air about 4-5 meters above the drone and over the cliff face. At the same time the drone tipped over (in the direction of the prop that came off) and the other prop next to it on the rear (battery facing) side shattered as the drone keeled over.
    The propeller that flew off was on the opposite side (undamaged/unscratched) to where the drone had hit the ground before. Now, I have scratched on front and back of the drone casing.I'm also alarmed the prop would fly off like that which i suspect meant the motor or some connecting component failed. (lucky it happened on the ground)

    What should i be checking at this stage? How to test in this situation before flying at height?
    Those batteries have had about 25-40 recharges and full discharge around every 20 charges (I keep a log). I noticed a few of the batteries are bulging slightly which i have heard is a sign to stop using them. I wouldn't mind if it was just one but all of them look like they are bulging a bit. Is it possible to change just the cells inside the batteries?
     
  2. Geoelectro

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    Re: Battery alert/problem led to hasty landing + damgage

    Have you been cleaning the battery connections? There's some threads on this subject. Since the batteries communicate digitally with the craft a bad connection can cause miscommunication. There are,four connections. Two for power and two smaller connectors for communication.

    Geo
     
  3. RichWest

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    Re: Battery alert/problem led to hasty landing + damgage

    Once the battery get past a certain point, percentage wise, auto landing initiates as you experienced. Any thrust now applied by you is off setting the auto landing decent. I was "testing" this out several weeks ago and experienced the same performance, now you know.

    As was mentioned, check the data pin terminals and the batteries for the data-pin pads. I believe the problem is between this connection point. The batteries are hopefully not what needs replacing, too little usage.
     
  4. eyecon82

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    Re: Battery alert/problem led to hasty landing + damgage

    Yea, it was descending because battery was lower than 15 percent.

    Dji implemented it in It's last firmware upgrade so they don't just fall out of the sky with low battery

    This feature alone has saved my Phantom 4 times. Lol
     
  5. Serpent

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    No harm in cleaning the battery connectors.. however if there was a problem with the connector, wouldn't it be a case of all or nothing in terms of battery power or battery data? As i was getting some information.
    I suspect a faulty battery is more likely the cause. Still wondering about the other problem which caused the rotor to fly off. That came from a different battery.
    I tested the bird again after - 1. span up without any props and then 2. with props on held the bird very tightly above my head whilst having someone work the controller. No problems showed.
    Do i assume it's okay for further flights with a changed (good) battery + replace scratched rotors?
     
  6. Geoelectro

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    No, not necessarily. Connect problems can be very short intermittent connections or a higher than normal resistance across terminals that can yield weak power or incorrect data transfers. People have had error messages like "Battery Communication Error", or "Invalid Battery" etc.

    It's a good idea to keep an eye on those connections.

    Geo
     
  7. rbhamilton

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    Not really related to this problem but I can tell you that auto-landing thing is freaky. I was flying along minding my own business. The battery hit 35% but it was bright out and I didn't notice it on the screen. No alarm or warning at all and the drone started sinking. It was over water. Akkk! Full power up just barely offset the descent and I brought it home quick. Everything was fine but I've got to turn that off! I don't mind RTH but this auto-land thing stinks!
     
  8. RichWest

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    On a recent flight I had a low battery alarm, still had more than 70% based on time in air. Within about 5 seconds it cleared. Why I read your topic. I'm wondering if the telemetry data is static rather than live. Possibly updated every so-many seconds... It would make sense from the aspect of reducing the data stream overhead. Like Geo mentioned, mine was a momentary thing.

    Curious if you'll (anyone) take a look at the data-pin terminal pads on your battery and see if you have what appears as 2-3 very small holes in the copper material where the pins would contact...let me know. I don't think it is an issue, but was curious if anyone else had a similar appearance.

    FWIW, my data pins appear to have three sharp points on each pin. I'm old, so my eyes are old... My data pads have the described three holes (or discoloration) on all 3 batteries. Could be a wear point, just wondering...if holes, solder would build up the surface just fine.
     
  9. Serpent

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    Thanks for your replies RW + RBH + GE. My next plan is to clean the terminals on battery and drone with alcohol and run that battery from a full re-charge to 0 with the props on and the drone secured (so can't actually fly for safety). I'll keep an eye out for any anomalies.