If you’re trying to enclose farm animals, an electric fence is practically a necessity. Yes, some animals, such as sheep, will generally stay inside a split rail fence with some hardware cloth over it. But other animals, like cattle or horses, have a tendency to break out if they’ve got a little incentive. To keep these types of animals in place, you need an electric fence. Electric fences aren’t just for keeping things in, either. Coyotes, wolves, and even bears can be deterred by an effective fencing system.
But an electric fence requires power, which means you need a reliable power source. If you’re on the grid, that’s easy. Just use a DC adapter to convert your AC power to 6V DC, and you’re good to go. But the power grid isn’t always 100 percent reliable. And depending on your location, you may not even have access to grid power. In those cases, you’re going to need a reliable backup. One solution is to use a solar array combined with deep cycle batteries. You’ll need to convert the 12V power to 6V, but that’s not terribly complicated. Another option, often used at the same time, is to use dedicated solar electric fence chargers.
The solar chargers we’re looking at today have their own internal batteries. They can electrify your fence, and will provide backup power in the event that the solar panel fails. First, we’ll be reviewing the Parmak MAG12-SP. This is a powerful, 3.1-joule charger, designed for larger pastures. Next, we’ll look at the Zareba ESP10M-Z. This is a medium-powered charger that’s easy to mount on T and Y-posts. Last, we’ll examine the Gallagher S10. This is a lower-powered charger that lasts for three weeks without power. Which one is the best choice for you? Let’s look at more of the details, and see how these chargers stack up.
What Voltage Do I Need?
The first thing you need to think about is how much voltage your fence requires. This is largely dependent on the type of animal you’re trying to contain. On the low end, a 500-watt fence is more than sufficient to keep chickens from running away. On the other hand, most people aren’t using an electric fence to retain chickens.
For beef cattle or horses, 2,000 to 3,000 volts is usually sufficient. The variation is due to the fact that vegetation actually draws away some of the voltage. If the fence is in high grass or scrub, you’ll want a higher voltage. If it’s generally trimmed clean, a lower voltage will be sufficient. One thing to note here is that bulls can become aggressive when they can’t access a cow in heat. When they decide it’s time to mate, a 3,000-volt fence may not be sufficient to retain them. For bulls, a 4,000-volt fence is going to be more appropriate, particularly with thick vegetation.
Along the same lines, you may need a surprising amount of voltage to keep out predators. Wolves can penetrate any fence that delivers less than 4,000 volts. For a bear or mountain lion, you’ll want at least 7,000 volts of power. More wires are also helpful for deterring aggressive animals, or for keeping bulls in check. You’ll also need to run more wires for small animals like chickens, to keep them from stepping through the gap.
Keep in mind that the rated voltage of any given solar output is based on use under rated conditions. If you put a power supply on a fence that’s too long, or with too much foliage, the voltage will be less. The only way to be sure of your exact voltage is to use a voltage tester. This will tell you your voltage in the real world, not just on paper.
Understanding Fence Charger Ratings
Determining the rating of any given fence charger is no simple task. This is because there’s no single standard for how to determine the amount of power. Are you running one wire? Three? Five? Is your fence obstructed, or is it kept clear? Depending on these factors, the same charger could be used to power a wildly different length of fence line. When reviewing any manufacturer ratings, keep in mind that they usually assume ideal conditions. With all of that being said, manufacturers provide their ratings in three ways: joules, miles, and acres. Here’s an explanation of what each one means.
Joules are a measurement of raw energy, equivalent to one watt-second. So a one-watt current delivers one joule of energy over the course of a single second. The problem with this is that it’s not a terribly useful measurement for electric fences. The current in an electric fence is very low amperage. Think about it. A 7,000-volt current, even at one amp, delivers a whopping 7,000 watts of power! That would be enough to kill any farmer unfortunate enough to brush against it. But electric fences deliver as little as 150 milliamps of power. Remember – it’s the volts that hurt, but it’s the amps that kill. It’s also important to remember that some manufacturers list “stored” joules, while others list “output” joules. Output joules are a better measure, since there are other, better measurements of battery storage.
Miles simply represents a measure of how long a fence line the charger can power. However, this comes with a huge asterisk. Multiple wires count as multiple miles. Let’s say your charger is rated for three miles. You can use it to power three miles of single-wire fence. However, if you have a three-wire fence, you’ll only be able to power a one-mile fence line. With a five wire fence, your coverage would drop to 0.6 of a mile, or about 3,186 feet. Vegetation will also lower your overall coverage distance. Keep in mind that you could theoretically use a charger for a larger fence than it’s rated for. You’d simply have to allow for a corresponding drop in voltage.
Acres are a measurement of the total area you can enclose with a given fence. Ideally, you’d be able to buy based on acreage, since it’s the measurement most farmers and ranchers are concerned about. Unfortunately, an acre can be any variety of shapes. Depending on the shape, you can easily see a 60% difference in fence line for any given acreage. In other words, looking at the acreage is a good way to get a rough estimate of a charger’s performance. But it’s no substitute for knowing how many miles and joules the charger is rated for.
The Parmak MAG12-SP is a robust solar charger that’s built to blend in on the farm. Instead of bright coloring, the main housing is plain brown, with a dull housing around the top solar panel. On the front of the housing, you’ll find a simple on/off switch. There’s also a voltmeter on the front, but it’s fairly basic. Above 2,000 volts, you’ll only have a vague guess as to your actual power status. It’s a decent way of knowing at a glance if something is horribly wrong. But if you want to do an actual voltage check, you’ll still need your own volt checker.
The MAG12-SP has large, plastic terminals for easily attaching your wires. You can tighten or loosen them even when wearing leather gloves, a useful feature while you’re working. The internal battery will deliver a charge of 3.1 joules, sufficient for 30 miles of fence at 6,000 volts. In other words, when used as intended, it’s capable of any task other than keeping out large predators. Unless you need to keep out bears or mountain lions, you should have no issue. The solar panel is sufficient to provide power all day, as well as to keep the battery charged. The battery, in turn, provides power overnight.
The housing is pre-drilled for mounting on a standard 6-inch T-post. If you’re mounting on another kind of post, you’ll have to jury rig your own system. However, the pre-drilled holes still make it easier to complete the installation. The housing itself is durable plastic, and is 100 percent weatherproof. It’s also backed by a 2-year manufacturer’s warranty to protect you from any defects.
The Zareba ESP10M-Z is a mid-sized charger that can power up to 10 miles of electric fencing. Its internal battery can supply up to 7,500 volts, enough to deter even bears and mountain lions. It’s also capable of powering up to 10 miles of electric fencing. Even with a five-wire fence, that’s two miles of fence line you can cover. Even better, the battery is designed to last through more than a single night.
When fully charged, it will last for up to two weeks without any sunshine. This might sound excessive, but there are times it can happen. For instance, the solar panel could get covered with snow. With a powerful battery, you don’t have to walk the fence and clear the panels every single day.
The housing is wedge-shaped, with the solar panel occupying most of the forward slope. At the bottom, there’s a bright yellow label, along with large red and green plastic terminals. There’s also a red light that lets you know everything is wired up and fully powered. The back of the housing is slotted, so it’s easy to mount on T-posts or Y-posts. It’s also shaped to be easily attached to six-inch wooden posts. All of this is covered by a 12-month manufacturer’s warranty, which includes lightning damage coverage.
The Gallagher S10 is a smaller solar electric fence charger, designed for smaller applications. It’s designed to power three miles of single-wire fence. That’s a lot if you only need a single wire. But for multi-wire applications, it’s better for gardens than for large pastures.
Even so, it’s more than up to the task. With 6,000 to 8,000 volts of power delivery, it can keep out even large animals. This is a godsend for beekeepers. You may only need to enclose a few hives, but you still need a fence strong enough to deter bears. In that case, the S10 will be more than up to the task. Despite its small size, the solar panel and battery are surprisingly powerful. It will work for up to three weeks without sun, which makes it very low-maintenance.
One thing we liked about the Gallagher S10 is how easy it is to install. It comes with a ground rod that can be inserted right into the bottom, along with an insulated carry handle. As a result, it can be easily positioned, pressed into the ground, and hooked up. It’s also exceptionally durable. You’re covered by a three-year warranty, the longest of any charger on our list.
As you can see, each of these solar-powered electric fence chargers has its own benefits and drawbacks. The Parmak MAG12-SP can cover the longest distance, with a rating of 30 miles. With a voltage of 6,000 volts, it can deter all but the largest of predators, and retain any kind of livestock. The power meter on the front is a neat touch, but it’s not as functional as it could be. A few more hash marks would cost the manufacturer pennies and be a major improvement. The main drawback is the battery. Parmak doesn’t provide any kind of rating. However, the two-year warranty is reasonably robust.
The Zareba ESP10M-Z is a medium-powered charger, suitable for covering about 10 miles of fence line. It provides superior voltage to the Parmak, though, with 7,500 volts. This makes it a better choice if you’re worried about very large animals. We also very much liked the design, which is easy to mount in many situations.
The Gallagher S10 is a better choice if you need to fence off a smaller area. With three miles of coverage, it can still deliver up to 8,000 volts, so it’s no slouch. It also has the longest-lasting battery on our list, and the best warranty. For a shorter fence, the S10 is truly the best solar charger available.