Shock!

Discussion in 'Electronics' started by Dan Coplan, Feb 21, 2013.

  1. Dan Coplan

    Dan Coplan Member

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    When I plug my batteries into my octo, it typically generates a spark. I've tried touching the metal leads to ground away any residual static but that doesn't seem to help. Anyone have any tricks for minimizing or eliminating this spark? Perhaps it's harmless, but I'd prefer to play it safe and not risk any spikes going down the line to my electronics.

    Dan
     
  2. Gary Haynes

    Gary Haynes Administrator
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    Dan, yes they spark. It isn't static, at least I don't think so. Grab the ends and don't hesitate when you plug them together. The more time you take with them hovering microns apart trying to be 'careful' the longer they will spark. Pretty spectacular isn't it? For fun try it in the dark with your dog sitting close by. Only kidding :)
     
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  3. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    What you are seeing is that the capacitors on the Power Distribution Board, when they are not charged up, look like a low resistance -- which gives you a big spark when you first connect them up.

    So, as Gary says, it's best not to hesitate. You'll get more sparks if you fumble with a Deans connector that an EC5 because the EC5 is generally easier to connect up.

    Contrary to what Gary says, do not this is the dark with your dog sitting near by.
    Only do it with someone else's dog. ;)

    Andy.
     
  4. Bill Collydas

    Bill Collydas Active Member

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    Dan, There is a way to do that. You use a restistor in line which you plug in first, then you plug in the main connector, I'll see if I can find the mod.

    Bill

    PS. Even if is not your own dog, you can get charged for cruelty to animals:oops:
     
  5. Bill Collydas

    Bill Collydas Active Member

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    Dan here you go. Resistors.jpg
     
  6. Nick Kolias

    Nick Kolias Moderator
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    Dan, in addition to the above, just a few more points. The spark does cause a very small pit in the contact material with each connection cycle. Depending on what connectors you use it's a good idea to keep a close eye on them and make sure they don't get too corroded over time. A nice advantage of the EC series connectors is that when the spark occurs it's out on the very edge of the contacts and doesn't affect the primary contact area when fully inserted.

    nick
     
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  7. Dan Coplan

    Dan Coplan Member

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    This is great info - thanks. Does the resistor need to be added to both negative and positive leads or is just one lead sufficient?

    Rather than splicing into my existing cables, if I build a separate "temporary" cable is it possible to touch the spark away safely and then put the temp cable aside and connect as I currently do?

    Dan
     
  8. Bill Collydas

    Bill Collydas Active Member

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    Dan you have to connect it to the positive side and it has to be soldered on the wire and has to be pluged in when you connect the battery.

    Bill
     
  9. Bill Collydas

    Bill Collydas Active Member

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    The spark occurs when you plug the battery wires in due to the capacitors are getting charged.
    With the resistor in place the resistor absorbs the current so there is no spark. What I mean by "absorbs" it reduces the current going through so the current travels slower the capacitors are still getting charged but at a slower rate.


    Bill
     
  10. Mike Jetter

    Mike Jetter New Member

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    I heard from Dan about this. Always wondered where the spark is coming from, even if it is obvious now.

    I kind of like the solution Bill pointed out, but I don't like that I have to modify the copter wire. So I thought about this solution instead:
    Create a short extension cable for your batteries and add the resistor mentioned in the article (e.g. 20 Ohm, 1 Watt for 4-5S batteries) in serial to the positive wire. The first time you connect the battery to the copter, use the extension cable to connect the battery. This will 'slowly' charge the capacitors of all ESCs. Once done (I guess after 5-10 seconds), unplug the battery, remove the extension cable and re-plug the battery to the copter. Since the capacitors are now charged, there should not be any spark.
     
  11. William Johnston

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    Another nice thing about the EC connectors is that when the spark occurs it's contained inside the plastic housing. With the Deans connectors you see the sparks fly. I never quite got use to that.
     
  12. Dan Coplan

    Dan Coplan Member

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    > A nice advantage of the EC series connectors is that when the spark occurs it's out on the very edge of the contacts and doesn't affect the primary contact area when fully inserted.

    Is that to suggest that while doing this resistor mod is worthy for reducing/eliminating the spark, there is little to no concern regarding the spark because there is still plenty of contact material that won't ever suffer the ill effects of sparking? I like this mod, but I am admittedly procrastinating sitting down to mod my copters and all my batteries.

    Dan
     
  13. Gary Haynes

    Gary Haynes Administrator
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    With all of the copters that are flying and all the sparks that are flying with them is the sparking really an issue? I don't think I have ever heard of anyone having a issue do to the hookup process.
     
  14. Ben Moyes

    Ben Moyes New Member

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    Hmmmm, no, it causes problems eventually.
    Depending on what type of connectors, the following can happen...
    After a lot if zapping, the contacts get all pitted and covered in carbon.
    The day comes when you hook it up, all seems fine, but the amount of metal on metal contact is small.
    You then fly, but with 50++ amps running through the small contact area, it gets hot...eventually vey hot.
    The plastic on the connector melts, and the solder is not far behind, and your machine performs an auto landing to cool down.
    Or something like that.

    Maybe make an anti zap circuit that hooks into the balance connector on the pack, that would be easy.
     
  15. Dan Coplan

    Dan Coplan Member

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    How do you propose doing that?
     
  16. Jim Swanson

    Jim Swanson Member

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    You don't want to fumble when connecting. Needs to be quick and decisive.
    One trick:
    Line up the both positives so their barely touching.
    Then roll the two negatives together...and push.

    You'll still get a spark, but only one.
     
  17. Dan Coplan

    Dan Coplan Member

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  18. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    They look like they might be a bit too easy to inadvertently connect up backwards -- yeah, I know, red and black, but....when you're in a hurry, in the dark, etc. Zzzzzottt.....

    Andy.
     
  19. Gary Haynes

    Gary Haynes Administrator
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    And no data on amperage.
     
  20. Dan Coplan

    Dan Coplan Member

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    Hard to tell from the pic but looks like you might be able to wire them short side/long side so you can't screw up the connection. They're not split evenly in half. And regarding the amperage, someone commented lower in the page..."You can use them easily for up to 12S and 150A( Will do 200A also )."
     

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