I'm about to get some chickens and was thinking that an electric fence might help to deter foxes. Does anybody know how the fence energisers work ? I thought I might try experimenting with an old ignition coil and relay to open and close the primary coil but I imagine that the primary current would be high. Any thoughts will be gratefully received.
Buy one. Roll-your-own electric fence chargers are a liability lawyer's wet dream.
Meanwhile, the foxes will just burrow under it and not be bothered a bit. If your chickens are not shut up tight at night, they are going to be eaten - so I'd suggest you put the effort into a nice tight coop, and remembering to shut it every night (and open it every morning).
Hugh Fearnley-Whittingstall is an advocate of the ladder system. The hen house is raised on an old telegraph pole, or similar stout support, to a height of about two metres. Access to the hen house is via a ladder, made by knocking simple steps into a long, stout pole. The design of the ladder is deliberately crude and rickety: a chicken will be able to use it, but a fox will not.
One could make such a ladder from a pole mounted in a bearing at either end and balanced so that the weight of a chicken will not cause it to rotate but that of a fox will. If a fox tries to climb it, it just rolls
Paul Hovnanian mailto:Paul@Hovnanian.com
You could have a metal patch on every second ladder step connected to an energiser. Chickens would use every step and not notice it, foxes being much longer, would use every second or more step and take a shock across their legs.
"Silicon Chip" has had at least three designs Apr 99, Jul 95 and Apr
Andy writes: I built on many years ago with a old Volkswagon ignition coil.
I used a 555 timer which put out a pulse about twice a second. This pulse drove a IRF620 hexfet which could switch 10 amps or so. The width of the pulse was experimentally determined to allow the coil current to build up to about 5 amps. The average current from the battery (12 V) was about 5 milliamperes.
I experimented with using the electric fence with goats, turkeys, and a cat........
Goats figure it out, and the first one to learn to go over/under the fence will show all the others.
Turkeys are just too dumb to care... I think they like it...
The cat sensed the electric field, jumped up on a post, and peed on me...
I suspect that a fox is smarter than a goat......
So, you can make your own fence charger cheaply, as I have done, but it may not accomplish what you want.... Good luck...
"Alan Beamish" wrote in news:hamzi.25193$ email@example.com:
They work by charging a capacitor (from AC mains current or a battery through a step up trasnformer driven by an oscillator, kind of like a heavy duty camera flash or strobe light), then discharging it through a step up trasnformer. They typically use a BJT transistor oscillator to trigger an SCR to dump the capacitor to the step up trasnformer, which is typically custom made. They usually output 1-6 KV per pulse, peak I guess. I have a special voltmeter for measuring that sort of fence, and thats what it reads.
Look up Gallagher fence chargers, they will have all sorts of info on them.