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What is a String Solar Inverter and How Does it Work?

An assembly of string solar inverters
An assembly of string solar inverters
Resource: https://renewablewatch.in

The string solar inverter is one of the most used inverter types today. It fits the budget of many solar projects, takes no time to set up, and has other benefits, such as being easy to use and maintain. This article guides string inverters, covering everything from their work to their advantages and disadvantages.

What is a String Solar Inverter?

If you’re new to solar energy systems, you might wonder what a string inverter is, why it’s called so, or even how it works. So we’ll start with the solar string inverter definition. After that, we will see how it’s built so you can get a clearer picture of its design capabilities.

String Inverter Definition

The string solar inverter describes a kind of PV system inverter meant to connect to one group or several groups of PV modules. It derives its name from linking to a “solar panel string” or multiple PV modules connected end to end to form a “string.”

The string inverter has been the most common type for residential, commercial, and other solar energy installations. Newer inverters, such as microinverters and optimizers, seek to optimize efficiency at the panel level and are available today.

But despite that, the string inverter solar system still has its benefits, especially when starting on a low budget or installing a large-scale solar system. We shall see about these types of inverters later when comparing them to the string inverter. For now, let’s focus on how to identify the string inverter.

Solar String Inverter Design

A solar string inverter comes in the form of a sizable unit that you install on a wall near your solar PV array, or it can be a device you place on a rack. It’s normally larger than micro-inverters or power optimizers, designed for installation on or near individual solar panels.

The typical string inverter will have multiple strings of PV modules connected to it. Consequently, it will have multiple inputs for these connections. Some inverters are designed with just one input and are built for small solar PV systems. These are sometimes called single-string solar inverters.

A multi-string solar inverter has multiple inputs. These allow users to connect several panels to the inverter unit. With more inputs, you can expand your solar system at will. You only need to add a few more panels and connect them to these extra inputs.

String inverter with power optimizer
String inverter with power optimizer
Resource: https://www.pv-magazine.com

How Does a String Inverter Work?

The string inverter technology is simple enough to understand. It takes the direct current (DC) electricity produced by a panel string and converts it into alternating current (AC) electricity. This is the type of electric current that’s used in your home or business and also the kind that’s fed into the utility grid if you have a grid-tied system.

Solar string inverters are “centralized” inverters, meaning they’re installed away from your solar PV array, and all of the DC electricity produced by your modules is routed to the inverter. These inverters are often used with batteries to store power for later use.

Solar inverters are generally efficient, especially when fitted with MPPT. However, for the efficiency to be realized when using a string inverter, solar panels in each string must receive sunlight, or the string or output will be reduced.

Given the working of string inverters, how do they compare to other solar system types? Let’s see.

String Inverter vs. Micro Inverter

A micro inverter is a type of solar inverter designed to be installed on or near an individual solar panel. It then inverts the DC electricity that one panel produces into AC power. This arrangement offers several benefits over that of a string inverter system.

First, it means a more effective installation. If one panel is shaded or faulty, only its output will be reduced. The rest will continue to operate unaffected. In a string inverter solar system, one malfunctioning or shaded panel minimizes the output of the entire string since all connect to it in series.

The advantage of string inverters is that they are much cheaper to buy and install than micro inverters. For that reason, they’re a popular choice when the budget is a crucial concern. However, micro inverters tend to have longer lifespans when compared to string inverters.

String Inverter Vs. Central Inverter

A central inverter is similar to a string inverter in many ways. Both are installed away from the solar PV array and are used to convert DC electricity into AC electricity by connecting to panel strings. Their differences are seen in the way they’re used and their sizes.

Central inverters are typically used for larger solar PV systems, such as solar farms, while string inverters are found in smaller systems. Another difference is that central inverters tend to be more expensive when compared to string inverters. This is because they’re usually more powerful, with higher voltage and current ratings.

String Inverter vs. Power Optimizer

A power optimizer is a type of inverter similar to a microinverter. Power optimizers are installed on or next to an individual solar panel. It then maximizes the output of that panel by compensating for any losses due to shading, soiling, or temperature changes.

Like micro-inverters, power optimizers can increase the overall efficiency of a solar PV system. But optimizers do not change DC Power to AC and must combine with a string or central inverter. So we can only talk about the power optimizer’s advantage in this aspect.

A string inverter with an optimizer provides a more efficient system than when used alone. Panel string monitoring is also possible using a string inverter with optimizers, like micro-inverters. These are significant advantages, especially for systems installed in shady or soiled areas.

Typical string solar inverter system
Typical string solar inverter system
Resource: https://www.saurenergy.com

What is the Best String Inverter?

Should you settle for a solar inverter, the next step is to identify the best string inverter for your power or solar energy needs. There are many things to take into account when selecting a string solar inverter. Here are some factors to keep in mind when making your selection:

String Inverter Capacity

The inverter you choose should be able to handle the amount of power your system produces. The power rating will determine how much electricity the inverter can handle. For example, a 3 kilowatt (kW) inverter can handle up to 3,000 watts of DC electricity.

When doing your string inverter sizing, choose a type whose power rating is slightly higher than the amount of electricity your solar PV system is expected to produce. Just to give you an idea, most homes use an average of 10 kilowatts (kW).

In addition to the string inverter capacity, you’ll also want to consider how much power your system is expected to produce in the future. If you’re planning on adding more panels in the future, make sure the inverter can handle the additional load.

String Inverter Efficiency

The string inverter efficiency rating will tell you how much of the DC electricity being fed into the inverter will be converted into AC electricity. For example, if an inverter has an efficiency rating of 96%, that means 96% of the DC electricity will be converted into AC electricity, while 4% will be lost in the conversion process.

A more efficient inverter will result in less power being lost during the conversion process, which means more power will be available to power your home or business. However, you should also keep in mind that string inverters are most effective when sunlight is available throughout.

Number of Inputs

The number of inputs is also an important factor to consider. The input is where the DC electricity from the solar PV array will be fed into the inverter. Most string inverters have one or two inputs, but there are some that have four or more.

If you have a small solar PV system, then a single-input inverter should be sufficient. However, if you have a large system, then you may want to consider an inverter with multiple inputs so that you can connect more than one string of solar panels.

Solar String Inverter Price

String inverters are the most affordable type of solar inverter, with prices starting at around $0.13 per watt. This makes them a popular choice for budget-conscious solar shoppers. The price you pay will depend on the features and specs of the inverter, though.

The solar string inverter price starts from around $100 to $1,000 or more depending on the available features and capabilities. Our advice is to compare the features of different string inverters before making your decision, whether buying the inverter for your home or solar energy business.

Don’t just settle for the cheapest option. Instead, choose the inverter that offers the best value for your money. A research of on the solar string inverter manufacturers and their products will provide you with the information you need to make your choice.


A string solar inverter is a popular option when investing in a PV or solar energy system. Affordable and easy to install and maintain, it provides a great solution for powering your home or business with solar energy. As you shop for a string inverter, keep in mind the power rating, efficiency, number of inputs, size, and price. Also, compare the features and specs of different inverters to find the best option for your needs.

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