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Battery switch

Discussion in 'General Discussion' started by Skylane765, Aug 30, 2013.

  1. Skylane765

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    Has anybody used a switch for the battery? It's a pain to unplug all the time, I'm going to install one. Also the compartment should have a rack for the battery so all you do is plug in and not hook the leads um all the time.

    I may make a mod for that and become a vendor here on the site.

    What I was also thinking is a battery case that goes over the battery and you install it in the Phantom, the as you close the door the door will have contacts that makes the connection and turn on the same way. Open the door and the power will shut off. It's a joke to pull on the wires to turn the Phantom on and off. At least a switch.
     
  2. thewizard

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    I think to put 3 separate switches in parallel. Then if there is a problem with the contacts on one switch, the other two will work. I will put the switches in different positions to prevent spontaneous turn off. More switches in parallel = more current throughput too.

    Sent from my GT-N7100 using Tapatalk 2
     
  3. Gizmo3000

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    I like the idea of redundancy.

    But I've heard it mentioned a few times that there's good reason not to have switches, as you don't want to risk failure. (plus just adds a bit of weight).

    I put my Aux power items on a switch tho, too much a hassle having my gimbal and fpv on all the time when connected to the computer,. etc.
     
  4. Skylane765

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    yes, I see why no switch, but two would be fine for the Phantom. I stake my life on 2 magnetos on my plane, so I would thing two on the phantom would be fine. It's seems that pulling on the connectors get broke loose after a while. We have locking switches and can be two pole for redundancy. That's what we have on aircraft, what amps do we draw on the Phantom?
     
  5. TickTock

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    I don't know what the peak draw is, but I had put a 20A switch on mine and it failed after about 5 flights.
     
  6. Skylane765

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    20 amp has to work, there is only 14 gauge wire to battery and that's good for only 15 to 20 amps.

    Let's say 2200 . The battery would last 2 min at about 18 amps? 4 min at 9 amps?
     
  7. will27

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    I use a switch for my FPV transmitter, which works quite well. Of course if it fails all I lose is FPV, but it's still going strong after 30 plus flights.
     
  8. Driffill

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    The max current draw of the ESC is 18a, times 4 gives you a possible 72A - not including the naza or any FPV, gimbal or BEC. Even using a 60A rated switch could cause voltage drop issues if the phantom tries to draw full power. . .

    Now imagine your phantom @xxxft high, giving it full throttle, or towards the end of the flight when the battery has drained down lower causing current draw to increase, and the switch failing . . . Can you picture it dropping from the sky? If its a drastic failure, it may cause a fire on the way down. I can understand why DJI DIDN'T utilise a switch.

    As for the wire gauge, my personal opinion is most manufactures (cars, toys, electrical) use the gauge that best suits the manufacturing budget, upgrading wire gauges (for DC systems) is generally a good thing to do where possible. . . . However, the "ratings" given to various cable gauges (in terms of current draw, A) are usually rated over 1 meter of cable, @25 degrees ambient temp, and 1.0 SAP (Standard Atmospheric Pressure), as those variables change, so does the failure point of the cable. Given the battery cable is only short, higher amperage could be drawn thru, tho only for short periods of time, as the heat produced could offset the short cable length . . . If that makes sense?
     
  9. Skylane765

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    I have a 8 amp 4 pole switch and it works great. The max load is about 12 to 15 amps, if the unit had a draw of 60 amps it would burn the wire to battery up. The new Phantom will have a switch on it, like the the phantom should have one now. I also used #12 tefttzel wire. The 4 poles at 8 amp = 32amp and 4 pole redundancy. He switch is rated at 6 amps each pole under a 8 amp load when switched. When I use the switch on the Phantom there is very little load.

    There is only 14 gauge wire used on the battery leads, I used 12. Checked after high loads and no heat on the switch or wires, but the battery gets warm. The new Phantom will have a 20 amp switch according to DJI.

    The switch is very short in length unlike the battery wire, the wires will heat up a bit under loads with #14
     
  10. Skylane765

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    DJI is going to use a switch on the new Phantom. Check YouTube with the interview. http://m.youtube.com/watch?v=Rht-QarvEM4
     
  11. bumper

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    Perhaps an "easier" way to get the increased current switching capability while still using a little mini size switch is to use the switch to provide the gate voltage for a mosfet such as IRFZ44N. Would require a small heat sink, but there would be unlikely to be any issues with switch failure.

    bumper
     
  12. Skylane765

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    No need for all that, the only time you use the switch is when very little current is used. With all that usd for a set up you now have more things to fail. Keep it simple like the switch on the new Phantom.