I have had several energizers over the years some good and some not so good.
Growing up on the farm was in the day before low impedance energizers. These chargers would shock you very good but they also "ground out" very easy. Some of the very earliest chargers were also continuous output. That means they didn't pulse on and off like most of the new ones do. Pulse is good as this gives the animal (or you) a chance to escape.
Fi Shock still carries a continuous output charger. The only reason I can think of to have one is to re-train a particularly stubborn animal. However, I think the best way to train livestock to electric fence is covered here.
For most applications you want a "low impedance" fencer. The term may seem to be a little misleading, but in actuality, low-impedance means that there is less resistance (or impedance) in the charger so more power can be pushed through the wire.
This type of charger is able to power through weed pressure and worse if needed. It's a must if you're fencing through areas where you have a high probability of deer tearing down your wire or tree limbs falling etc.
I recently went around checking fence on an area that hadn't anything in it since last summer. I hooked the section of fence and tested the voltage. It was reading 4 kv on my tester. It usually runs around 9 kv so I knew it had some areas that were partially grounded out.
I walked around the perimeter and found tons of sticks laying on it and two places where the wire was completely buried under the wet leaves for probably 25 feet!
That's the power of low impedance! 4 kv on my charger will keep a trained pig in where he belongs forever.
My current charger which is pictured above is from Fi Shock. It is rated at 15 joules. There is a technical definition for joules, but to keep it simple it's the amount zap the fencer will push out.
The higher the joules the more power to keep your stock in over long runs of wire.
The biggest mistake you can make when buying an electric fence energizer is to not go big enough. Pigs can take a shock. I've had 3 joule chargers before and they will hold pigs in just fine provided you're not running too many feet/miles of wire on it.
But I noticed with those chargers the pigs have a habit of getting their nose in the fence more at feeding time. All it takes for a pig to get out is to figure out the wire is off and they are out and running.
With this 15 joule charger they don't have any interest in getting their nose on it! They do from time to time, but instead of a short squeal and a jerk, they scream and then woof two or three times after that! It get their attention.
Finally, although I'm not going into installation here, the one area that needs the closet attention is grounding your energizer. The biggest most powerful charger is worthless without being grounded properly. Follow the manufactures directions and don't skimp!
Pigs and other livestock are wonderful if they stay where you put them. With a good electric fencer energizer and some training they will stay in the pasture where they belong.
Until next time...