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Short Flight times SOLVED! So Stoked!

Discussion in 'General Discussion' started by Idahomojo, Oct 6, 2013.

  1. Idahomojo

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    I have been dealing with 3 minute flights for about 2 weeks and I think I finally figured it out. After a flight today I went to unplug my battery and the power wire from the control board broke off the yellow battery connector. It looks like only a strand or two had been connecting the DJI to the battery for several days. I resoldered the connection and no my flight times are back up to 5:30.

    So, to the electrical engineers out there. Does that sound like it could have caused the problem? It seems to have solved it.

    And I am happy it broke while I was on the ground and not at 300 feet.
     
  2. Audaciter

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    Even five and a half minutes seems pretty short, unless your Phantom is very heavy.

    Do you have a lot of equipment on it ?
     
  3. Idahomojo

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    I run it with Hero 3, Fatshark FPV, Futaba 8J rx, and Arris 200 gimbal. I am pushing close to maximum weight.
     
  4. Audaciter

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    Yeah, that's gotta be pushing maximum density. ;)
     
  5. martcerv

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    Lucky you didnt get a complete power failure in flight then before finding the issue. Its a good thing to check everything over every now and then and if having some new strange issues then its a great time to give everything a thorough look over.
     
  6. discv

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    These Lipo connectors, all of them, are just not suited to the continuous plugging and unplugging, especially given the physical force needed.
    A dry solder joint will quickly deteriorate, and a lot of your stored power will evaporate in the form of heat.

    There is room for a designer here to come up with a connector that offers strain relief to the cables. In much the same way that a normal domestic plug does not rely on the electrical connection for it's integrity.

    I've been fooling with this idea for a while now, but cannot find a way that does not add bulk, which in the case of the Phantom, would present issues with the battery door.

    The basis of my ideas is some form of mould that is temporarily fitted to the connector. Some form of resin would then be injected to bond the connector and cables as one.Resin sets and mould removed for future use.

    Intellectual rights reserved on this idea :geek:
     
  7. deluge2

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    I guess there's always room for another innovation though it sounds like silicone would do what you're talking about, if applied and allowed to cure correctly.

    As to the question of physical force, since the connectors are pulled apart by gripping only the two housings (never pull on the wires), the solder joints themselves don't feel the connect/disconnect forces, or at least they shouldn't. If they do, you're doing something wrong.

    The wires are subject to bending forces when wires are manipulated tucking batteries in and such. Also there is some flexing from craft vibration in flight. However a properly formed joint using quality multi strand wiring should last a long time, like years. Perhaps the original joint was never right. Never heard of a 'dry' solder joint, but cold solder joints are one form of defective solder joints. A cold joint is an accident waiting to happen. The best strain-relief connector housing will simply delay the inevitable.

    The other thing that happens is overheating the wire when the connector is attached causing solder to wick up along the wire too far from the joint itself (too little heat applied for too long heats bother the wire and the connector too much). This creates a sharp ending of the solid soldered part of the wire beyond the heat shrink tubing strain relief. Bending forces lead to fatigue and failure.

    Steve

     
  8. Peter Patricelli

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    Martcerv and discv bring up two important issues.

    1) Since it is easy to assume full charge and take off and fly at distance assuming no reason to start watching for the warning lights, OR to not hear the warnings, there is danger of major crash if the battery is not fully charged. There are apparently battery checkers? I didn't see the need for one until I read this and thought it through.

    2) The connectors, actually the whole connection system, is NOT ideal. My stock battery connector gradually got looser and looser in terms of ease of connecting/disconnecting and then began re-starting the boot cycle while stuffing the wires in before a flight...meaning it was losing contact momentarily during manipulation. I consciously thought I wouldn't want such a temp disconnect during flight, but stupidly did nothing about it.....with the predictable result. The problem is, I believe, that the battery-female tube enlarges and the male Phantom post may get constricted by the tightest battery with the result that it gets loose gripping the smallest male post among your battery sets.

    I toyed with the idea of an electrolytic-conducting grease but couldn't find what I wanted......and wasn't sure that was the way to go. My final/temporary solution is to re-spread slightly the male posts in the phantom connector, which are bisected to flex, giving tighter contact again on the smallest, apparently, battery female receiver. But do THAT enough, flexing it, and the end result eventually will be metal fatigue. I am a long way from that...but there certainl is room here for a better mousetrap.
     
  9. yalag

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    How do you guys know when the battery is about to run out? I guess there's a red light or something but usually my phantom is so far away, how would you even know? Do you guys do test where you float the phantom right in front of you and then let it run dry and see how long it lasts?
     
  10. netphreak

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    Usually, yes. That's why there's two timers on the futaba.
     
  11. Skylane765

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    I installed a switch and that is what they all need. The new ones will come with a switch. I also have switch for gimbal and v alert.
    [​IMG]
     
  12. Gizmo3000

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    you know it's bout to run out when the red lights blink and you have to start giving it more throttle to stay in the air.
    and you know it's run out when it slows drops from the sky and lands itself (if you're lucky)