Here's one that popular with backpackers for bear fences, sold by UDAP.COM. It uses 2 D cells and costs 50% more than the Kencove. They don't give a joule rating in their specs. When I bought the Kencove, I did a lot of looking and at the time, it was the best one of it's type for the money.
With most chargers, it's operation is highly dependent on the ground and whether the animal has good ground contact. When those are equal, most chargers will do the job. The question is how long the fence needs to be. More powerful chargers will operate longer fences.

I've heard about campers training bears by smearing peanut butter on the wires or hanging some kind of conductive bait bag on the wire and pouring water on the ground by it. That attracts the bear and he gets shocked. Usually they learn. When I read about a bear that keeps going through a fence, I have to question whether he's in contact with the ground.

[Linked Image from udap.com]


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