Fence energizers, also called fence chargers or controllers, are devices that deliver short, high-voltage pulses to an electric fence wire to deter animals from crossing the fence boundary. The energizer stores energy from a power source and releases it in pulses of 5000 to 10000 volts lasting 1/3000 of a second. The pulse delivers a sharp but safe shock that teaches animals to respect the fence without causing injury. Energizers are rated by the amount of stored energy in joules, with higher joule ratings required for longer fence lines and heavier vegetation. Electric Fencing covers the wire and installation components of the fence system.
Mains-powered energizers, operating on 110 to 240 volt AC household current, deliver the highest output and most consistent performance. They are the most economical option for permanent fences near buildings and are rated from 1 to 15 joules. Battery-powered energizers use 6 or 12 volt deep-cycle batteries and are suitable for remote paddocks. A 12 volt, 100 ah battery powers a 1 joule energizer for 4 to 8 weeks between charges. Solar-powered energizers combine a photovoltaic panel with a battery in a single unit. Solar energizers are rated by the panel wattage, typically 2 to 15 watts, and deliver effective performance in areas with 5 or more hours of direct sunlight daily.
Energizer sizing is based on fence length, vegetation contact, and animal species. A general guideline is 1 joule of stored energy per 10 kilometers (6 miles) of fence under light vegetation, or 1 joule per 3 kilometers (2 miles) under heavy vegetation. The energizer must be grounded with a minimum of three galvanized steel ground rods, each 1.2 to 2 meters (4 to 6 feet) long, driven into permanently moist soil at least 10 meters (30 feet) from utility grounds and water lines. The fence voltage should measure 3000 to 5000 volts at the far end of the fence under load.
The primary cause of energizer performance loss is vegetation contacting the fence wire, which drains the pulse energy to ground. Fence line vegetation should be cleared regularly. The ground rod system should be tested annually by measuring voltage between the ground rod and a temporary test rod driven 2 meters (6 feet) from the ground system. A reading of 300 volts or less indicates adequate grounding. The battery voltage on battery and solar systems should be checked monthly. Fence Building covers the mechanical installation of fence posts, wire, and gates.