How to pair a battery energizer and solar panel

When choosing a solar panel for your battery energizer; energizer draw (amps), available sunlight per day, and battery size all affect the output wattage needed.  

Determining the solar panel wattage needed to supply an energizer with power is relatively simple. To do so we use the Power Formula, P = EI. P is the wattage required, E is the battery's voltage, and I is the energizer's amperage draw.

Example, an energizer with a 100mA (.1 amp) per hour draw and a 12v battery would require 1.2 watts per hour, 28.8 watts or 2.4A throughout the day. The solar panel needs to supply the 2.4A to the battery in order for it to remain charged.

Now the fun part. It's not sunny 24 hrs a day. During the summer months, Premier receives about 5.5 hours of usable sunlight at our farm in SE Iowa (the panels are not tracking the sun). (Charts below indicate average hours of sunlight based on location and time of year.) This means the battery will be the sole power source for 18.5 hours "overnight". That's 1.85A. The panel will have to produce a days worth of energy in only 5.5 hours. That would be 2.4A/5.5 hours = 0.44A per hour. Recall that P=EI, so P = 12V x 0.44A = 5.3 Watts. A 5.3 W panel would provide enough current to run the energizer during the 5.5 hours or sunlight, plus enough current to replace what was used overnight.

Summer sunlight, hours available per average day. 

Winter sunlight, hours available per average day.

What about cloudy days where the panel is not supplying current? Assume Day one was sunny and the battery was topped off at sundown. Day two is cloudy. Sundown to sundown is 24 hrs, plus another 18.5 hours until Day 3 when the sun rises. That's 42.5 hours or 4.25A that needs to be recharged within 5.5 hours. Don't forget we also need to power the energizer until sundown on Day 3, so add .55A to that total, 4.8A. What's the wattage required? 4.8A / 5.5 Hours = 0.87A per hour. P = EI, 12V x .87A = 10.44 W.

The battery size determines the the number of days the energizer will run without sun light. The solar panel determines how many days it will take the battery to recover to full charge after a cloudy day(s).

For those wondering, what size energizer uses 100mA per hour? Most units in the 1 joule output range consume that much power.
If an out-of-box solar energizer kit does not fit your needs, a set-up to fit your situation can be easily designed using the formula above. Happy fencing!

Picking a fence and energizer combination—did I get everything right?

If picking out an energizer or roll of netting for the first time strikes you as a daunting task don't worry—it does not need to be tedious.

When visiting Premier's website—below the logo and slogan are a series of tabs, Sheep-Goats-Poultry-Horses-Garden/Wildlife-Deer-Cattle-Hogs/Pigs-Camelids. (Before we go any further, camelids is a one word way of saying llamas and alpacas.)

Tabs shown above. 

Select the relevant tab for your fencing needs—I'll select sheep. Go to the left hand column and click on Fencing.


Your fence options should now be shown. Since we're discussing netting, we'll focus on the temporary and semi-permanent options. The main differences being, how often do you intend to move the netting? Daily/weekly—choose temporary. Less often? Semi-permanent.

Fencing options for sheep (Semi-Permanent options not shown). 

From there you decide on Plus or Standard nets (post frequency), length, height, strut or string verticals and type of spike. Don't forget support posts for ends, corners and any major directional changes.

Now that you've chosen your fence, it's time to choose an energizer. Unless you already have one, in that case you're done!

Click back over to Fencing and select Energizers (DC, AC or Solar).
At the top of the results select energizer comparison chart. This will take you to a chart detailing all of Premier's energizers.

Click on the type of unit you need, AC (plug-in) or DC (battery or solar).

In the upper right corner you can again select the type of species you are fencing. Scroll right and you will find the number of nets each energizer can power. There is a range, (i.e. 2-5, 3-6) depending on energizer output in dry grass/soil conditions. If your soils are typically moist, go with the higher number and vice versa in dry conditions.

Energizer power source are the selections at the upper left. Species type is at the upper right. (Energizers can be used for multiple species.)

These options should help narrow down energizer and net choices. As always, if you have any questions give us a call at 1-800-282-6631 and we'll help you out.




Coming soon—advanced filters to help narrow down your netting and energizer selections.

Energizers: Plug-in, Battery or Solar

(left to right) Battery energizer, plug-in energizer and solar energizer. 

When choosing an energizer here is one very basic thing to keep in mind—is it going to be a battery, plug-in or solar energizer. Note: solar energizers are battery energizers with added bells and whistles. 

With that in mind, what are the differences between the two basic types?

Plug-in—power source is a 110v outlet. Permanently located. 

Battery—power source is a 12v battery. Easy to relocate. 

• A plug-in energizer is left in one location (usually close to an outlet). An insulated cable is used to carry the pulse from the energizer to the fence. 
• Battery energizers are typically set close to the fence and away from any convenient outlets. They draw off a 12v battery. The pulse travels through a short wiring harness to the fence. 
• Battery energizers cost more overall b/c of the need to purchase batteries and a battery charger. 

What about solar energizers?

Solar energizers are extremely convenient to use. Fences can be set up in the middle of nowhere. Depending on hours of usable sunlight, batteries rarely need recharging (but do keep an eye on them). 

The downside is the cost. The battery, panel, case, regulator (for high output panels) add to the price tag. That and if the sun doesn't shine for multiple days (the PRS units are sized for a 4-day reserve) the voltage on the fence will drop as the battery drops below a 40% charge). But for many convenience outweighs costs, hence why solar energizers are popular. 

Which to use?

If the energizer gets to stay in one place—we recommend plug-in energizers at every opportunity. No batteries + no reliance on sun = less hassle. 

If portability is needed, use a battery energizer. 

If portability with added convenience is desired, solar is best. 

If you have questions please call us at 800-282-6631 or email info@premier1supplies.com