The electric fence is a great choice for homeowners or farmers to ensure their pets or animals safety. Fence chargers are the heart of the fence system, providing the source for the electric current that flows through fence wire. Fence chargers, also known as energizers or fencers, vary by amount of current they output and their power source.

The energizer (also called a fencer) is the cornerstone of any electric fence. Selecting the right one for your farm is crucial to making an electric fence work for you. Understanding electricity and all the jargon that goes with it can be a challenge. Luckily, thinking about water is often a great way to imagine electricity, so I’m going to draw comparisons between electricity and water throughout this article.

The first step in selecting an energizer is to determine your power source. If the fence is close enough, an energizer that plugs into the hydro is often the cheapest and easiest solution. As the fence gets further away from an outlet, running wires becomes expensive and other power options start to look more attractive. Deep-cycling 12 volt marine batteries are another potential power source for an energizer. These work best when you have at least two to swap out – one battery can charge while the other powers the energizer. An energizer being powered by batteries needs to be fairly accessible, so that batteries are easy to change before they run down. For electric fences in more remote locations, a solar panel may be the best solution. These tend to be the most expensive power source for a fence, but because the panel recharges the battery, it’s less likely to lose power than batteries alone. For solar panels to be effective, they need to receive a minimum of 4-6 hours of direct sunlight every day.

An electric fence is a psychological barrier: livestock learn not to touch the fence because the shock is unpleasant. Untrained animals or a non-electrified fence may enable livestock to go right through the fence, because it is not physically strong enough to stop them. To ensure the fence is “hot” enough to convince livestock to stay in the paddock, you need enough voltage. Volts are a measure of electric potential. If we draw a comparison with water, voltage is akin to water pressure. See Table 1 for minimum output voltages. Check that the energizer can deliver an appropriate amount of voltage.

Choosing the right size of fence charger for your livestock is crucial for keeping them safely contained. It's essential to consider the specific needs of each type of animal and select a fence charger that provides enough energy and voltage to deter them without causing harm. By using the joule and voltage scales provided in this article, you can make an informed decision and ensure the safety and well-being of your animals.

The most economical power source (hydro, batteries, or solar) depends on ease of access to fencer

Output voltage needs to be high enough to get the attention of the livestock being contained

Output joules rating must be capable of delivering the voltage along the length of wire in the fence

When in doubt, buy bigger than you need