# Homemade fence charger



## Heritagefarm (Feb 21, 2010)

I am going to make a fence charger instead of buying one; I have the time but not the money. I'm looking around at diagrams, trying to find one to fit my needs. I need to make one that has a lot of power, perhaps 10 miles of fence with a zap to make anyone leave it alone. Anyone have any experience with this? Just thought I'd check. Thanks in advance for any replies!


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## agmantoo (May 23, 2003)

Using a distributor from an old vehicle figure out how to drive the shaft that is driven by the cam. Then using a vehicle battery replicate the spark sytsem for firing the sparkplugs. Drive the setup to where you get approximately 60 RPM and feed the coil output to the fence. This lengthy voltage duration can possibly start a fire so be careful.

If you do not like this design then rig a turn signal flasher to fire the coil. It needs the same disclaimer as above.

Buying a vehicle battery driven current design ParMak impedence charger that gives a short spark and that is Underwriter Lab approved may have a lot of merit, especially in court.


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## sticky_burr (Dec 10, 2010)

could you use a 555, or similar timer triggering a relay?


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## PyroDon (Jul 30, 2006)

model T coil 
if your looking for a way to pulse or break point open an old fashioned door or telephone bell


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## Heritagefarm (Feb 21, 2010)

I am looking at this one. I unsure if the power would be sufficient, however.
http://www.brighthub.com/hubfolio/swagatam-majumdar/articles/92394.aspx


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## Allen W (Aug 2, 2008)

I've got a Par Mak Magnum 12UO fencer coming from Valley Vet http://www.valleyvet.com/ct_detail.html?pgguid=63714a46-814d-11d5-a192-00b0d0204ae5 for 91.00 with shipping. Swapping out the oldest vehicle battery for a new one for a power source for the charger and I'm good to go. It isn't worth the risk to me to build one.


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## Heritagefarm (Feb 21, 2010)

I am now confused about what "impedance" means. Does this mean that if there are weeds it will impede the charger, which means I need a high-impedance charger?


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## agmantoo (May 23, 2003)

In non-technical terms, low impedance means the fence charger is designed to effectively shock through vegetation and other foreign matters contacting the charged wire. Vegetation such as grass, weeds, vines, etc., contacting the charged wire tend to impede or stop the flow of electricity by "grounding out" the fence. This is a common problem which exists on most electric fence installations. The low impedance fence charger is a solid-state capacitor discharge design and has enough power to force the shock through vegetation.


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## Heritagefarm (Feb 21, 2010)

agmantoo said:


> In non-technical terms, low impedance means the fence charger is designed to effectively shock through vegetation and other foreign matters contacting the charged wire. Vegetation such as grass, weeds, vines, etc., contacting the charged wire tend to impede or stop the flow of electricity by "grounding out" the fence. This is a common problem which exists on most electric fence installations. The low impedance fence charger is a solid-state capacitor discharge design and has enough power to force the shock through vegetation.


Thanks, that helps a lot! I was reading this post:
http://www.homesteadingtoday.com/showpost.php?p=4996287&postcount=3
And it says he uses a 100 mile fence charger rated for 12,000 volts and 6 joules. 
Now, what I'm planning on doing is running 1 strand of hotwire around the perimeter of about 18 acres and 8 acre paddocks, and then cross-fencing. That's the plan. Do you think that powerful of a fence charger would simply be overkill for 360 feet of polyfence? 
Also, how does the joule part compute?
http://muller.lbl.gov/teaching/Physics10/old physics 10/physics 10 notes/voltsampsetc.html
"Watt (power) = 1 joule per second
The watt is a unit of power. One watt is equal to one joule per second. The power P it takes to send current I through a wire is given by:

P = V I

A bright lightbulb consumes about 100 watts, i.e. about 100 joules every second. "
Does this mean a 6 joule fence with 12,000 Volts will deliver... Um, well, normally I'm good at math but it is 10:30 right now!


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## Allen W (Aug 2, 2008)

I received my new fence charger today, very pleased with it. The built in meter makes it easy to see the fence condition.

Heritagefarm unless you have sheep or goats I think the 100 mile fence charger is over kill for your acreage. I would stay away from anything rated less then 30 miles they don't have enough bite.


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## Heritagefarm (Feb 21, 2010)

Allen W said:


> Heritagefarm unless you have sheep or goats I think the 100 mile fence charger is over kill for your acreage. I would stay away from anything rated less then 30 miles they don't have enough bite.


I have sheep and goats. I just realized, however: How will lambs and kids do with 20,000 volts? It doesn't last very long at all, but is it enough to harm them?


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## Rogo (Jan 1, 2006)

May be of no help to you, but for many years I've had a Parmak 12 volt solar fence charger. It covers 30 miles of fencing and cuts through vegetation. Says it'll work for 5 days with no sun, but I haven't been able to test that -- I live in the sun belt! -G-

Good heavens. Didn't realize I was on the cattle site. Oh well. Hope you find an answer.


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## Allen W (Aug 2, 2008)

Heritagefarm said:


> I have sheep and goats. I just realized, however: How will lambs and kids do with 20,000 volts? It doesn't last very long at all, but is it enough to harm them?


The shock from a fencer is more like a static electric shock then the shock from an electric outlet. I'm sure it wouldn't be good for them if they were caught in the fence, but it shouldn't be harmful if they were just shocked by the fence.


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## Heritagefarm (Feb 21, 2010)

Does anyone have any experience with a 20,000 volt charger (w/ intermittent) and lambs/kids?


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