You’ve probably heard of an inverter if you’ve spent any time looking into solar energy.
Your solar system’s brain is the inverter. It controls two types of power and manages your energy flow.
The type of power stored in batteries is DC (direct current). It’s also what solar panels create.
However, you cannot power anything in your home with DC electricity (directly). This is when your inverter enters the picture.
AC (alternating current) power is used throughout your home. An inverter converts DC power from solar panels (or batteries) into AC power for your refrigerator, lights, television, and other household equipment.
Isn’t that easy?
What’s the difference between an off-grid and a grid-connected inverter?
A grid-tied inverter converts DC solar electricity to AC and transmits it into the grid for credit.
Because there are usually just two primary components (the inverter and your solar panels), grid-tied inverters are simpler and easier to wire. (Although some grid-connected systems are beginning to include energy storage, the vast majority do not.)
A battery bank, on the other hand, is required for an off-grid inverter to work.
Here’s how it works: your solar panels charge the batteries with DC power. The power is then “inverted” by your inverter, which produces AC power for your home. It functions in the same way as a tiny power grid.
If your system is properly set up and designed, your inverter will not deplete your batteries. Your solar panels and charge controller power the battery bank, which is supplemented by a backup generator throughout the cold season.
Off-grid systems, as you might expect, are more complex due to additional components such as the charge controller, battery monitor, and additional AC and DC circuit breakers. All these factors contribute to off-grid systems being more complex to wire and install.
Purchasing off-grid equipment can also be difficult because to the numerous connected accessories, such as remote controllers, battery monitors, breakers and enclosures, surge suppressors, and so on.
Choosing the proper parts is difficult enough, but selecting the right inverter is the most important decision you’ll make.
How to Select the Most Effective Off-Grid Inverter
Consider the Size
The first thing to consider is how much power you will require.
Off-grid inverter sizing is simple if you know what appliances you’ll be using.
To figure out how many watts you’d need if all your lights and appliances were turned on at the same time, add up the wattage of all your lights and appliances. (No, you won’t utilize everything, but it’s a simple way to be safe.)
Remember to factor in the voltage—while most appliances operate on 120 volts, some, such as well pumps, require 240 volts. Example: Assume you require 1,000 watts for your refrigerator, 500 watts for lights, and 200 watts for your phone and television. This amounts to 1,700 watts. In this instance, a minimum inverter size of at least 2,000 watts is recommended to provide you with some breathing room. (After all, you may add appliances later.)
What is our most popular size? 4kW, then 8kW. Different models and brands come in a variety of sizes, and most of them may be stacked for increased power output.
Instead of using a modified sine wave, consider using a pure sine wave
Pure sine wave inverters may be mentioned by some manufacturers. It’s not necessary to comprehend how this function; all you need to know is that the power generated by a pure sine wave inverter is “cleaner” than that generated by a modified sine wave inverter.
Pure sine wave inverters produce higher-quality power output that is comparable to (or better than) that of our power grid. Modified sine wave inverters are less expensive, but their power output is of inferior quality.
Modified sine wave inverters, as a result, may cause problems with specific gadgets. Motors, pumps, and compressors become hotter and wear out faster because of this. Certain delicate gadgets, such as computers, may be damaged or cease to function altogether. These inverters also generate background noise on stereos and poor video and audio quality on some televisions.
That’s why we don’t suggest modified sine wave inverters for most situations; to prevent these concerns, most of our off-grid customers utilize pure sine wave inverters.
Do you need a simple way to tell the difference between the two? Examine the total harmonic distortion (THD) rating of your inverter. THD is a measure of the output power quality and can be found on the specifications sheet of any competent inverter. As a rule of thumb, use a pure sine wave inverter with a THD of 5% or less to avoid getting into difficulties.
Look at the technical details
Here are some more technical details to think about:
When your inverter is performing properly, this is the amount of electricity it can supply to your home from the batteries. Peak efficiency ratings of 94 percent to 96 percent are considered good.
No-load current draw, or self-consumption
How much electricity would your inverter need simply by sitting there? Obviously, you want to keep this to a minimum.
Capacity to handle a surge
What is the maximum amount of short-term overload that the inverter can sustain before it “trips?” Some equipment, such as pumps and refrigerators, require 2–3 times their normal operating power to start up.
The output of the battery charger
Many off-grid inverters come with a battery charger, which may be used to recharge your batteries with a backup generator during the cold season. The battery charger has a rating, which is commonly expressed in amps. A battery charger in the range of 50-100 amps DC is standard on most quality off-grid inverters.
Range of temperatures
Extreme heat has a negative impact on inverters. If you want to install your system in your garage or somewhere else where it will be exposed to temperature extremes, pay close attention to the temperature range.
Warranties normally last from one to three years, with a few manufacturers giving a 10-year warranty extension option.
All these features are usually listed on the product specifications sheets. Consult your solar expert for assistance in comparing and selecting the best inverter.
It’s possible that your inverter will require additional features. Look into the following:
Charger of battery
A charger allows you to charge your system using a backup AC generator. This is included in most larger inverters, which are referred to as “inverter/chargers.”
Ability to connect to the grid
Some off-grid inverters can also feed power into the grid, as seen in the following examples:
Schneider Electric XW+
SMA Sunny Island
If the grid becomes available in the future, or if you’re setting up a grid-tied system with battery backup, this option will come in handy.
Automatic start-up of the generator
Most inverters and charge controllers can handle this, however some inverters and charge controllers can’t.
Do some research on the company
It is also necessary to be aware of the inverter’s manufacturer. Look up their background and track record. Off-grid inverters must operate 24 hours a day, 365 days a year, for several years, so pick one from a reputable manufacturer.
Only a few companies make high-quality inverters for this application, according to our experience:
• Advanced inverters
• Ideal for bigger, multi-inverter systems
• Some of the most technologically advanced inverters on the market
• Proven manufacturer
• A wide range of products
• Made in the United States
• Simple to set up
• Superior quality
• Outstanding reputation for dependability and durability
Check for UL certifications and approvals
For safety and code compliance, off-grid inverters must have several different certifications.
UL 1741-approved inverters are required for your home. UL 458 certification is required for mobile inverters in boats and RVs. Other standards for various uses include the UL 1778 standard for uninterruptible power supplies and the KKK-A-1822E standard for emergency services, such as ambulances.
Other standards, such as CSA 107.1 in Canada and IEEE 1547 in other countries, are necessary.
Remember to factor in the cost
You should also consider the inverter system’s pricing (including all essential components) and the features you obtain for that price.
Make sure to compare prices for all required components, such as the remote control, circuit breakers, mounting plate, and any other items needed to install the system.
Using a Pre-Wired Power Centre is another viable option
A power center is an off-grid inverter system that comes pre-wired and includes everything you’ll need, including an inverter, charge controller, remote control, and circuit breakers.
A battery monitor and surge suppressors are included in most of the power centers we sell for monitoring and protection.
Off-Grid Inverters at their Finest
Your inverter choice is largely determined by the size requirements and application, however, here are a few of our favorites:
Our Pick for the Best Off-Grid Inverter for Cabins and Small Homes is the Magnum Energy MS-PAE.
4kW-4.4kW 120/240Vac output
24-volt or 48-volt battery bank
The MS-PAE series of inverters is available in two sizes: 4kW 24-volt and 4.4kW 48-volt.
Magnum Energy’s inverters are simple to install and operate. They have strong surge protection and battery chargers. There’s also a Magnum Panel system with a back plate and breaker panel (to make a complete power center).
When these inverters are installed on a Magnum Panel, the normal guarantee is increased to five years.
A battery monitor, automated generator-start (AGS), and MagWeb kit for remote monitoring are among the accessories available.
For years, the MS-PAE Magnum Power Centers have been our most popular power centers, both for off-grid cabins and small residences.
Multiple MS-PAE inverters can be stacked together for a total output of 17.6kW, making this inverter ideal for larger off-grid residences.
The 4kW 24-volt variant is perfect for cabins since it can cope with smaller battery banks and solar arrays.
Magnum inverters come in a variety of capacities and are reasonably inexpensive and simple to install, making them an excellent alternative for off-grid cabins and homes.
Conext XW Pro by Schneider Electric
Best Large Off-Grid Inverter, in Our Opinion
• Output of 6.8kW at 120/240V
• Battery bank with 48 volts
The XW Pro inverter operates with a 48-volt battery bank and has a 6.8kW output power.
For three-phase power systems, multiple inverters can be stacked together, and groups of three can be combined.
A power distribution panel, automatic generator-start, and battery monitor are among the accessories available from Schneider. With larger, multi-inverter systems, the Schneider XW Pro system shines.
Schneider can accommodate up to 102kW output power in numerous clusters of inverters for big industrial and commercial applications. Lithium batteries are also supported.
All these capabilities, as well as the flexibility to stack inverter clusters, make the XW Pro our top pick for massive off-grid power needs.
Radian by Outback Power
The best off-grid inverter for grid-tied battery backup systems:
There are two models available: GS4048A-01 and GS8048A-01.
Output of 4-8kW at 120/240V
Battery bank with a voltage of 48 volts
The Outback Radian is an off-grid inverter that can also sell your excess electricity to the grid.
This is the best option if you want battery backup and grid-tied solar, or if you’re off the grid but think grid access will be accessible in the future.
The Radian inverter system contains powerful software for remote monitoring and control called Optics RE, which allows you to monitor your system, receive warnings about any failures, and modify settings remotely. It can also start and stop generators automatically.
This is currently the only battery-based inverter with grid-tied interconnection approval in the United States. It’s also the only grid-tied battery backup inverter on the market that meets the most recent grid-tied system connectivity regulations in California and Hawaii.
It comes in two sizes: 4kW and 8kW, and numerous inverters can be stacked for a total power output of up to 80kW.