Table of Chargers
Use this link for a table showing which electric fence chargers are best for dealing with specific animals and situations.
Charger Safety, Horse Fences, and Joules
In general, each of our low impedance chargers for electric fencing is safe because the pulsed nature of the charge means a shocked person or animal has no difficulty letting go of the charged conductor. Also, chargers for electric fences put our very little power. Their unit of power, the joule, is defined as 1 watt applied for 1 second. Compare this to the more familiar kilowatt hour (a value 3.6 million times as great), and one can see that even quite strong chargers for long electric fences are not putting out enormous amounts of electricity in their short pulses. (They do put out very high voltage, which gives them great shocking power, but very little actual electricity). In this vein, one should note that the joules put out by the charger can vary considerably depending on the resistance (in ohms) of the electric fencing, and that typically as the ohms decline from 500 (minor weed burden) to 100 (major weed burden) to 50 (huge weed burden) the joules put out by the charger increase, so that most of the time a strong charger is putting out a good deal less than its joule rating. Even so, there is always the remote possibility that an animal or person might get entangled in electric fencing, which is one reason why any electric fence charger above about 3 joules should be used with a modicum of caution. Another reason is that one does not wish the electric fence charger to administer a shock strong enough to panic a horse in a small enclosure–especially an electric fencing enclosure to which the horse is not accustomed.
Therefore, it makes sense to err on the side of caution and to use a relatively weak electric fence charger (0.2-0.5 joules) to protect barrier fences from horses that like to lean or chew on them, and also to power small temporary paddocks and corrals. Use a stronger (0.5-1 joule) charger to electrify moveable interior pasture fences. Employ a more powerful (1-2 joule) controller to charge small permanent enclosures whose boundaries the horses will typically know. And use an even stronger (3 joule or over) charger to electrify large permanent fences, to deter escape-prone horses, or to cope with difficult conditions.
In this latter regard, please note that our more powerful (6 to 18 joule) AC-powered chargers are good at coping with relatively large weed burdens—because they will typically put out about 3 joules if the weed burden is slight (in the neighborhood of 500 ohms); but they will then substantially increase their output in the face of larger weed burdens (ones that provide a 100 or even 50 ohm path to the ground) in order to compensate for the power that the weeds are draining from the fence.
