How to Choose the Right Fence Charger

Use the right fence charger to contain your livestock, including cows.

Also called an energizer or fencing unit, your fence charger plays an essential role in your electric fence by converting electrical energy into a high-voltage charge that streams through the insulated wires on your electric fence. In order to install an electric fence that successfully contains livestock in a pasture or excludes animal pests from your vegetable garden, you'll need to select a fence charger that can provide the necessary amount of electric energy to your fence wires. Before you begin your quest for an energizer, develop a thorough understanding of your electric fence ahead of time, including the number and type of wires you plan to use, as well as the animal species your fence will be used for.

Instructions

1. Determine the most appropriate power source for your electric fence. Opt for a plug-in, 110- or 120-volt fence energizer whenever possible to provide the most reliable energy source for your electric fence. Go with a solar-powered charger if your electric fence is located away from electrical outlets but has an open area with plenty of sunlight available. Use a battery-operated fence charger for electric fences located too far from electrical outlets but close enough for you to check them and replace the batteries regularly.

2. Measure the length of the wire that you'll be charging in your fence. Look for an energizer that provides enough electrical energy to easily cover the entire length of all your combined fence wires. For example, if you plan to construct a 7-wire electric fence that encircles a 2-mile pasture perimeter, you'll need to choose a fence charger that can handle minimally 14 miles of electric fence, preferably more if you suspect your electric fence may make regular contact with weeds and other vegetation that can needlessly drain energy from your wires.

3. Check the energizer joule rating; according to Premier One Supplies, an electric fence manufacturer in business for over 30 years, electric fence energizers vary greatly in energy output, with some producing as little as 0.05 joules and others releasing up to 40 joules. (see reference 2) Multiply the joule rating on a fence energizer by six to determine if the energizer can handle the amount of electric fence you're using. Make sure the resulting number is equal to (or greater than) the number of miles of wire you'll be charging in your fence. For example, a 2-joule energizer is most likely too small to consistently power a 2-wire fence around a cattle pasture with a 10-mile perimeter (20-miles of electric wire), but it would provide more than enough power for a two-wire cattle fence with a 4-mile perimeter (8 miles of electric wire).

Tips & Warnings

• Shop around at several different fence supply stores. Talk to knowledgeable fence energizer dealers at each location to see which units they recommend. Share the size information and purpose of your electric fence, as well as the type of animal your fence is for, so they can help provide the most accurate recommendations for your personal fencing situation.

• According to Oklahoma State University Cooperative Extension, joule ratings can be subjective and vary widely between energizer manufacturers, depending upon factors such as the fence wire testing location and the type of wire used during the test.

• Never try to make your own fence charger or purchase one that was homemade. Although you may be able to save on initial cost, these energizers are a potential electrical hazard and may cause fires.

References

• Oklahoma State University Cooperative Extension: Fencing (pdf)
• "Fences that Work;" Premier One Supplies; 2010
• University of Wisconsin Cooperative Extension: Fence Energizers (pdf)