Below is cut/paste of PDF page 5, from Montana FW link above. Cutting to the chase, MTFW recommends energizer with MINIMUM 0.5-0.7 Joules OUTPUT.
(Note: I've never used such a fence but have read up on them for some time. The only 1.0 Joules Output energizer I've seen is from Bear Sentry, who claims 1.8 Stored and 1.0 Output Joules. I guess you could buy the same energizer Bear Sentry uses, and make up your own kit if you wanted.)
(Here's the cut/paste)
1. Energizers Energizers are the power source for your electrified fence. Energizers come in a wide variety of makes and models, but all of them are designed to store energy and deliver it in short pulses through the connected wires.
To effectively deter bears, your energizer needs to pulse at a rate of 45-60 pulses per minute, which is approximately 1.0-1.5 pulses per second.
Energizer manufacturing companies rate their products with an energy measurement unit called a JOULE. A Joule is a measure of stored OR released energy.
The Joule rating of energizers typically have 1 of 2 classifications; Stored or Output. The Stored classification is the maximum number of Joules that the energizer can store when not delivering energy to a fence.
The Output classification is the maximum number of Joules that the energizer can deliver to a fence. The number of Joules Stored will always be higher than Output.
For example, an energizer listed as having 1.0 Stored Joules will be able to deliver approximately 0.7 Joules to the fence. The amount of Stored or Output Joules does not directly translate to the amount of voltage an energizer can deliver, nor to how powerful the electric shock will be.
The higher the Joule rating of an energizer means it has a higher amperage. It is amperage, not voltage, that determines how powerful a shock will feel.
For example, while both a 0.2 Joule and 1.0 Joule rated energizer can deliver a 7,000-volt shock, the 1.0 Joule energizer has higher amperage. Therefore, a 7,000-volt shock delivered by a 1.0 Joule energizer will feel more powerful than a 7,000-volt shock from a 0.2 Joule energizer. In plain terms, a 1.0 Joule energizer has a more painful shock value than a 0.2 Joule energizer.
Bears are more likely to pay attention to an electrified fence that delivers a painful shock.
Therefore, for deterring bears in developed areas, your energizer will require a minimum Joule rating of:
0.7-1.0 Stored Joules or 0.5-0.7 Output Joules.
Low cost, slow pulse rate, low Joule rated energizers are abundantly available and may be adequate for livestock or pet-yard applications. However, these energizers will not be effective at deterring bears.
Similarly, older energizers that were not designed with modern safety features may be unsafe to use. And high Joule rated energizers are too powerful for small applications; bigger is not necessarily better.
bearwatchsystems.com
