Need help to lower shock from electric fence

Discussion in 'The Projects Forum' started by TSmith, May 22, 2013.

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  1. TSmith

    Thread Starter Member

    Sep 21, 2010
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    We got a battery operated fence energizer. It runs off two D batteries and puts out a pulse about every 2 seconds. We got it to try to keeps some cats from digging and pooping in my wife's flower beds.

    We also have a couple very small 6 pound dogs and my wife thinks the zap is too strong and wants me to reduce the zap so the fluffies don't get their nose zapped too hard.

    Before I open up the unit and void the warranty, I was hoping to get some input from the folks here. I take it there is a step up transformer that charges a capacitor and a chip programmed to discharge it every couple seconds.

    My question is: Can it be as simple as replacing the existing capacitor with a smaller one to reduce the force of the zap?

    It does zap a lot harder than needed despite operating off of only 2 D cells. It has a 1 mile range and I only need it for 100 feet.

    [​IMG]
     
  2. MrChips

    Moderator

    Oct 2, 2009
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    No. You cannot lower the voltage that simply. Your dogs will get used to it and stay away. That's how it works.
     
  3. TSmith

    Thread Starter Member

    Sep 21, 2010
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    While my wife was not home I turned it on and one fluffy already went against the wire. She let out a good yelp and went back inside the house. It will be easier for me to spend the time to lower the shock than to argue with my wife that the purpose of the shock is to hurt...
     
  4. Dodgydave

    Distinguished Member

    Jun 22, 2012
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    The circuit will have an oscillator and pulse transformer that steps up the voltage similar to this circuit so unless you have the circuit yourself it will be difficult to modify.
     
  5. crutschow

    Expert

    Mar 14, 2008
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    Some high value resistors in series with the output will reduce the intensity of the shock. Try values of 100kΩ to 1 megΩ to start.

    Changes are, once the dogs are zapped once or twice, they will learn to stay away from the wire.
     
  6. TSmith

    Thread Starter Member

    Sep 21, 2010
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    crutschow - Are you saying to put the resistors inline from the output of the shocker and the connection to the fence wire?

    I know that if branches are touching the wire it will reduce the electricity reaching the other end. As an alternative, what if a wire with x amount of resistance is put inline between the fence output and the ground? Would that be a way to absorb some of the electricity so not all of it travels past that point?
     
  7. MrChips

    Moderator

    Oct 2, 2009
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    If you did that the electric fence would not work. You will bleed away all the charge and the voltage will be next to nothing. That is how anti-static grounding straps dangling from vehicles work.
     
  8. TSmith

    Thread Starter Member

    Sep 21, 2010
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    It still zaps you even with some plants touching the wire. That is why I thought it might work.
     
  9. #12

    Expert

    Nov 30, 2010
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    Some details here...if the shocker is setting the voltage it wants and if you make the capacitor smaller, you can reduce the total ENERGY. Too many, "if's". A resistor in series with the output is soo simple and soo cheap, and doesn't foul the warranty or expose you to making a mistake.

    Personally, I let my puppies chew on live 120 volt house current wires. Totally able to kill them! The first time a damp puppy tooth touched a live wire, they figured out that the wire can defend itself, and I never killed a puppy. I never even heard one of them yelp. Your wife, like mine, wants to make sure the puppies do not learn not to chew on wires. I say puppies are not so stupid that they will keep going back until it kills them, and I proved it with an experiment. Now...if I could only figure out how to do that with shoes...
     
  10. poopscoop

    Member

    Dec 12, 2012
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    There are only a few parallels between the human and canine mind. Pain processing and threshold is not among them. I know it probably doesn't help, but your wife needs to understand that applying human perception to a dog is a waste of time. I've literally watched a dog run itself to death; They are tougher than we are.

    I have a small understanding of dog training. If you want it to be easier on them, clearly mark the wires or the area they're in with a contrasted color, a sizable object, or a unique scent. Maybe run some scented oil along the wire. The dog will learn to associate that object/sight/scent with pain, and avoid it after the first shock.

    Don't know how much a resistor is going to lower the voltage on what is probably a microamp of current. I doubt your multimeter will survive a measurement.
     
  11. poopscoop

    Member

    Dec 12, 2012
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    No idea if that will make a measurable difference, but if you can convince yourself and your wife it does, then that's the best option. After all, lowering the intensity of the shock is for your piece of mind, the dogs don't care.

    Most electric fences are meant to pulse a specific number of times a second, say 10. The idea is that you can control your muscles and pull yourself off of the fence at 10 pulses a second. At 20 and above that becomes more difficult, which is why tasers operate in that range. If you reduce the size of the capacitor you may increase the frequency to a dangerous level, depending on the timing constant of the circuit.
     
  12. TSmith

    Thread Starter Member

    Sep 21, 2010
    57
    2
    I like the scented oil idea. That way all I need to do is put some of the same scent in areas I don't want them to go and that just might work!

    Thanks for all the tips. I'll experiment with the resistors a bit and try the scent idea too. Now I need to figure out how to lessen the zap to me each time I touch the wire to test it!
     
  13. edwardholmes91

    Member

    Feb 25, 2013
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    I can't help but think this exercise is a little fruitless. The idea of an electric fence is to keep animals from crossing. As others have said, they soon learn not to touch it when they get a nasty shock. They are designed for this exact purpose and they are designed not to be lethal. The idea of the oil though like you say could be a good idea. And as you have pointed out... if it works you could use it anywhere you like even if there isn't an electric fence present. I personally wouldn't risk tampering with it because not only will you void the warranty if you do any permanent changes, you could make it more dangerous.
     
  14. Marcuse

    New Member

    May 15, 2015
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    Take the back off and stare into it intently until she leaves. Later, tell her you put a reduction capacitance modulator in it. It will still STS out of the dog, but the dog will touch it only once. And when he does and goes arw arw arw arw arw you say, "It would have been a lot worse without that reduction capacitance modulator on it."
     
  15. crutschow

    Expert

    Mar 14, 2008
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    Why are you replying to a 2 year old post? :confused:
     
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