Solar Inverters - What Are They & Which Are Best?

What is a solar inverter? How do they work? And why are they an essential part of any modern day solar panel installation?

A solar inverter is an essential component of any solar system.

The inverter converts the energy output from solar panels (direct current) into consumable electricity (alternating current) that can be used in your home or fed back to grid.

The inverter is typically equal to either 120 volts or 240 volts depending on the country.

Without a solar inverter in your system, you would be unable to power your home safely using the energy you generate via your solar panels.

Solar Inverters UK Key Points:

Solar inverters convert solar panel DC electricity to AC electricity for use or feed back to the grid.
The main types include string, microinverters, and power optimizers.
String inverters are most common and affordable, but microinverters and power optimizers can be more efficient and have a range of other benefits.
Consider size, capacity, features, quality, and work with a reputable installer.
Regular maintenance and monitoring are important for effectiveness.
Solar inverters are just one part of a solar energy system.

What Does a Solar Inverter Do?

To summarise, a solar inverter performs the following roles:

Converting DC electricity to AC electricity.
Optimizing power output.
Establishing communication with the National Grid.
Providing feedback on power production.
Ensuring safe operation of your solar PV system.

AC-to-DC Conversion

A solar inverter plays a crucial role in generating solar energy.

It converts the direct current (DC) electricity generated by the panels into alternating current (AC) which is the typical electrical flow needed to run your home’s appliances and establish a connection to the National Grid.

Usually, the current is equivalent to either 120 or 240 volts but this depends on which country you live in.

Simply said, you couldn’t use solar energy to power your house without a solar inverter securely.

Check our quick help solar energy guides here:

Maximize Power Output

Solar inverters continuously monitor the voltage of the solar array to determine the highest power over which the modules can operate.

Grid Support

With the grid, new smart inverters have improved from one-way communication to two-way communication, assisting with grid-supporting function.

Thanks to sophisticated software, smart inverters can do several grid-supporting operations involving communication, frequency, voltage, and controls.

Ensure Safe Operations

When an electric arc occurs, which is conceivable due to material deterioration and system aging, solar inverters are supposed to shut off.

Here is an insightful video that shows you a working example of a solar battery storage system that includes car charging capability:

How Does a Solar Inverter Work?

Electricity in DC is kept at a constant voltage in one direction.

As the voltage in the AC changes from positive to negative, which means that the electricity flows in both directions.

Inverters are traditional components of a family of devices known as power electronics that regulate the flow of electrical electricity.

Technically, an inverter converts DC to AC by rapidly flipping the direction of a DC input. As a by-product, a DC input transforms into an AC 120V/240V output.

This is how it works: The light shines down on your solar panels (or photovoltaic (PV) cells), which are comprised of crystalline silicon or gallium arsenide semiconductor layers.

These layers are a combination of positive and negative layers connected by a junction. When the sun shines, the semiconductor layers absorb it and transmit it to the PV cell.

This energy bounces electrons around, causing them to flow between the positive and negative layers, generating an electric current known as direct current (DC).

Once generated, this energy is either stored in a battery for later use or transferred directly to an inverter (this depends on the type of system you have).

The electricity that is being transferred to the inverter at this stage is in DC format, but your home appliances need it in AC format to work.

The energy is taken in by the inverter and passed via a transformer, which produces an AC output.

By making the transformer behave like AC, the inverter essentially “trickles” the transformer into believing that the DC is truly AC.

To do this, it passes the DC through two or more transistors that rapidly turn on and off and feed two different sides of the transformer.

Types of Solar Inverters in the UK

Solar inverters come in four variations and below are the major traits of each one.

String Invertors

The panels are arranged into groups linked with strings, hence the name.

Many panel strings can be linked to a single inverter, transforming the panels’ direct current electricity into appliance-friendly power.

A single inverter can support the connection of multiple strings, and many string inverters contain two or three MPPTs (Maximum Power Point Tracking).

This implies that each MPPT can support a distinct string of solar panels. This is perfect for an east/west configuration because it will maximize the sun generation from the two strings of panels.

Pros: Apart from less purchase, labor, and installation costs, the additional benefit of a string inverter is that you only need one of them to convert the DC current coming from your solar array to AC power.

The inverter is most likely to malfunction in a solar system, which makes troubleshooting very simple when something goes wrong.

Cons: Due to the series wiring, if the output of one solar panel is affected, the output of the entire series of solar panels is affected in equal measure.

This can be a significant issue if a portion of a solar panel series is shaded during some part of the day. String inverters have a shorter lifespan and are difficult to expand.

A string inverter system also does not actually enable panel-level insight because there are no components mounted to the rear of each panel to accomplish the job.

Micro Invertors

A micro inverter system fixes the issue where a solar panel system on a string inverter is affected by a malfunction or shadowing on a single panel.

This is because in a microinverter system each individual solar panel has an inverter to itself, therefore isolating any issues. This makes microinverters more flexible to add more solar panels at a time.

Shaded areas as well as the orientation of solar panels are no longer an issue.

Although they end up being more expensive to purchase and install, they are a microinverter system that is anticipated to improve your solar energy production and, consequently, return on investment.

Pros: Microinverters are aimed to generate more electricity from the sunlight due to their improved orientation.

According to the new electrical standards, microinverters must meet these rapid shutdown criteria, and each module has this capability built in.

Their surprisingly long lifespan of 25 years approximately surpasses all the typical inverters’ lifespan which is only 8 -12 years.

Apart from the fact that they are easier to expand, Microinverters do support the panel-level monitoring feature.

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Cons: Generally speaking, microinverters are not recommended because of their expensive cost.

Moreover, if one of your microinverters broke, it would be difficult to identify which one it was, and if you did, servicing and replacing the part would be more difficult than just installing a new string inverter on the side of your house.

To restore AC conversion capabilities, your solar installer would have to climb back onto your roof, work with your racking system, unbolt the solar modules, and replace the microinverter.

Hybrid Solar Invertors

A hybrid inverter is definitely something to take into consideration when establishing a new Solar PV system with storage.

An inverter is required to convert DC electricity produced by solar panels into AC electricity in order to power the appliances in your home.

Solar batteries, however, only hold DC-format electricity. In addition to converting the incoming DC power into AC, a hybrid solar inverter can transfer any excess DC power to be stored in a solar battery or sold to the grid.

The electricity can then be inverted to AC to be utilized in your home when your saved energy is needed.

Pros: Especially when compared to conventional energy sources, a hybrid solar inverter is a low-maintenance device.

A hybrid inverter does not need to be serviced frequently because there is no fuel involved.

Hybrid inverters can be integrated directly into your solar battery, and therefore centralize the monitoring of the array’s performance.

Cons: The cost of hybrid inverters is 50% higher than the cost of string inverters.

Furthermore, they can only work with DC coupled batteries, which can occasionally restrict your options for batteries.

If you already have Solar installed and are looking to add a battery to your system, then financially it makes sense to install an AC coupled battery system over a new inverter.

Power Invertors

Power inverters provide similar benefits as micro-inverters are placed on every single panel.

Power inverters, also referred to as DC power optimizers, provide panel-level optimization and performance monitoring.

In contrast to a micro-inverter system, the optimizer transfers the DC power to a string inverter rather than converting it directly to AC at roof level.

It is probably installed close to your battery storage system. They frequently cost less than micro-inverters since they operate at the module level.

Micro-inverters can be replaced by power inverters at a lower cost. Power inverters minimize the effects of shade and even mismatched modules, allowing for maximum energy generation.

They provide maximum energy conversion efficiency and negligible voltage fluctuation.

Quick help guides:

Solar Invertors Conclusion

Solar energy systems are becoming more and more popular as a result of the global growth in interest in renewable energy sources.

It is quite beneficial for the environment and makes excellent use of a source of energy that we have available for many hours each and every day.

The solar needs of each house and residential property are unique.

In the end, a smart way to determine what solar inverter you should invest in is to calculate the amount of energy your home or facility would need.