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27 Dec 2023

How to Determine the Efficiency of Solar Inverters?

Solar Inverter Sizing: Don't violate the new CEC guidelines! - Solar Quotes  Blog

When it comes to solar power systems, every component plays a critical role in ensuring maximum efficiency and output. However, one component that is often overlooked but is equally important is the solar inverter

A solar inverter may seem like a small part of a solar system, but it plays a crucial role in converting the energy obtained from the sun into usable electricity for your home. In essence, it acts as a bridge between the DC energy produced by your solar panels and the AC electricity needed to power your appliances. 

Without an efficient solar inverter, your solar system will not be able to function optimally, and you may miss out on the many benefits of renewable energy, including maximizing your savings on energy bills. That’s why investing in a high-quality solar inverter and understanding ’inverter sizing’ is crucial for any homeowner looking to make the switch to clean energy.

Here is everything you need to know about picking an efficient solar inverter!


Guide to designing off-grid and hybrid solar systems — Clean Energy Reviews

Photo Credit: Clean Energy Reviews

How Efficient are Solar Inverters

Solar inverters are highly effective, typically achieving efficiency levels of 93-96% depending on the specific brand and model.

It's important to note that they are never 100% efficient due to the power they consume to operate, typically ranging from 10-25W. However, there is a technique called Maximum Power Point Tracking (MPPT) that can enhance their efficiency.

What Factors Influence the Efficiency of Solar Inverters?

Many factors play a part in inverter efficacy, including sizing, but some are environmental. There are things you should keep in mind when maximizing the potential of your solar inverter.


Geographical elements play a crucial role in sizing your solar inverter. Regions with high temperatures tend to receive ample solar radiation, resulting in greater electricity generation compared to areas with lower temperatures. 

Geographical features such as buildings, trees, or mountains can cast shadows on solar panels, reducing their exposure to sunlight. This shading can impact the overall efficiency of the solar inverter. It's essential to assess the surrounding environment and ensure that the solar array is positioned to minimize shade and maximize solar energy intake.

These temperature and solar radiation variations result in different levels of DC production at any given time. In normal weather conditions, the solar inverter is expected to achieve maximum output based on specified DC ratings.

Time of Day

The efficiency of solar panels and inverters can vary throughout the day due to changing solar radiation levels. Peak sunlight hours typically result in higher efficiency.

Design and Installation Area

Location plays a significant role in determining the size of a solar PV inverter and is influenced by factors such as the design and installation area of the solar array. The orientation of panels and shading can affect overall inverter efficiency. 

The orientation and tilt angle of solar panels affect their exposure to sunlight, which ultimately influences the efficiency of the solar inverter. Proper alignment maximizes energy capture. Shadows from buildings, trees, or other obstructions can significantly impact the efficiency of solar panels by reducing the amount of sunlight they receive. Correct positioning and installation can help minimize shading effects.

Electrical Mismatch

Mismatched panels or improper electrical connections within the system can lead to reduced efficiency. Proper installation and system design are necessary to minimize electrical mismatches.

Size of Solar Inverter

The size of the solar inverter is a crucial factor to consider, as it needs to be able to handle the electricity generated by the solar array's DC output. Selecting an inverter with a size or capacity similar to the DC rating specified on the solar panels is important.

For example, if you are installing a 6-kilowatt solar energy system, the inverter should have a capacity of around 6,000 watts, with a slight tolerance for variation.

Pro Tip: Remember that using an incorrect size of inverter can compromise the warranty and the overall efficiency of the solar PV system.


Calculate Inverter Size - Solar Stik

Photo Credit: Solar Stik

Why Is Solar Inverter Efficiency Crucial for Solar Power Systems

The solar inverter is the conductor of your solar array. It is responsible for converting the DC power generated by solar panels into usable AC power that can be used in homes or businesses. 

The efficiency of the solar inverter is crucial because it directly affects the amount of power that can be generated and used. A high-efficiency solar inverter ensures that more power is produced than wasted as heat and that the system operates optimally. In summary, solar inverter efficiency ensures maximum solar power generation and reduces energy bills.

Where to Access Information on Solar Inverter Efficiency Ratings

Typically listed on the product sheet of the solar panels, these efficiency specifications indicate the maximum capacity that the inverter can handle. It's crucial to ensure that the chosen inverter matches these size requirements to avoid any potential warranty issues or performance degradation. 

Failing to do so could result in irreversible damage to your solar system and ultimately, a decrease in energy efficiency. Armed with the correct information, selecting the right inverter will help you reap the full potential of your solar panels and make your investment even more valuable.

Typical per unit efficiency curves for grid-connected solar inverters. |  Download Scientific Diagram

Photo Credit: Research Gate

How to Calculate and Measure the Efficiency of Solar Inverters

The efficiency of a solar panel system is heavily influenced by the efficiency of the inverter, which converts DC power from the panels into usable AC power for the electric grid. The sizing of the inverter, whether over-sized or under-sized, can impact the overall performance of the system.

Oversized Solar Inverters

Oversizing an inverter refers to installing a solar array with a higher capacity than the inverter's rating. This can result in increased daily power production, especially during periods of optimal solar irradiance. However, during periods of low solar irradiance or partial shading, an oversized inverter may be unable to extract the maximum power output from the panels, leading to diminished performance.

If you have plans to expand your solar panel array in the future, it may be advisable to install an inverter with a maximum capacity greater than the nominal capacity of your current array. However, this recommendation may not hold true universally as there are certain considerations to consider. It is important to note that when using an oversized inverter, the overall energy yields from your solar system may be lower than those with a perfectly sized or under-sized inverter.

Inverters are typically designed to handle lower power inputs than their nominal capacity. It is recommended to consult with your installer to understand better how your system will perform with an oversized inverter. This query could include discussions on how the overall energy yield of your system would differ over the next 5-10 years with an oversized inverter compared to a "right-sized" or under-sized inverter. It is crucial to weigh this information against the cost implications of different system configurations before making a final decision.

Undersized Solar Inverters

On the other hand, undersizing an inverter involves selecting an inverter with a lower capacity than the solar array's rating. This can be a smart choice when building a solar system as it can increase the daily amount of power produced. However, it may limit the system's maximum power output and potentially result in lower energy yields.

Irrespective of the solar panel output, the inverter will limit (or "clip") the power output to ensure it does not exceed the inverter's rated capacity.

Solar Inverter Sizing Guide

It is important for users to consider the size of the inverter in relation to their solar panel array to optimize the efficiency of their system. Proper sizing ensures that the inverter can effectively handle the power generated by the panels. This ultimately enables users to make better decisions regarding their current or future solar photovoltaic installations.

How can you size your perfect solar inverter? 

  1. It is essential to ensure that the size of the inverter matches the DC rating specified on the solar panels.
  2. To determine the array-to-inverter ratio, it is recommended to divide the DC rating of the solar panel array by the maximum AC rating of the inverter. In many installations, the array-to-inverter ratio typically falls within the range of 1.15 to 1.25.
  3. As a rule of thumb, when installing a 7-kilowatt solar energy system, the chosen invert should be around 7,000W.


Why Aren't My Solar Panels Producing 100%? | Option One Solar

Why Opt for High-Efficiency Solar Inverters in Your Solar Setup

High-efficiency solar inverters offer several benefits that make them a favorable choice for solar installations. These inverters are designed to convert more electricity from the solar panels efficiently, minimizing losses during conversion.

A super efficient inverter can convert a higher percentage of solar energy, save more on your power bills over time, and even extend the longevity of your solar system. 


How to Monitor and Maintain the Efficiency of Solar Inverters

Monitoring and maintaining the efficiency of solar inverters is essential for optimizing your solar power system's performance and overall longevity. 

  • Solar Monitoring System: To effectively monitor your inverters, consider installing a solar monitoring system that tracks the output and performance of your panels.
  • Analyze Data: Regularly analyze the data collected by the monitoring system to assess important metrics such as energy production, voltage, and current. 
  • Follow Manufacturer Directions: Follow maintenance tips like ensuring proper ventilation, cleaning or replacing air intake filters, monitoring error codes, utilizing solar monitoring technology, and conducting regular physical checks.


Best Solar Inverters of December 2023 - CNET

When to Consider Upgrading to More Efficient Solar Inverter Models

Upgrading to more efficient solar inverter models can be wise under certain circumstances. These are some of the reasons that might tip you towards a solar inverter upgrade. 

Decreased Performance

If you notice a decline in the energy production of your solar power system, it may indicate that your current inverter is not operating at its optimal efficiency. Upgrading to a more efficient model can help improve the overall performance and maximize energy output.


Technological Advancements

The solar industry is continuously evolving, with advancements in inverter technology leading to higher efficiency and improved features. If your current inverter is outdated and lacks the latest technological innovations, upgrading to a newer model can unlock additional benefits and ensure you stay up-to-date with the latest advancements.


System Expansion

If you plan to expand your solar system by adding more panels, assessing whether your current inverter can handle the increased capacity is essential. Upgrading to a more powerful and efficient inverter can accommodate the expanded system and optimize its performance.


Inverter Age and Warranty

 Inverters have a limited lifespan, typically ranging from 10 to 15 years. If your inverter is approaching the end of its lifespan or has surpassed it, upgrading to a new, more efficient model can provide better reliability and peace of mind. Additionally, check if your existing inverter's warranty has expired, as this can be an opportune time to consider an upgrade.


Are You Ready to Maximize the Financial Benefits of Your Solar System?

Upgrading to a more efficient solar inverter can contribute to significant long-term financial savings. Higher efficiency means extracting more energy from your solar panels, reducing electricity bills and potentially faster return on investment. Consider conducting a cost-benefit analysis to evaluate the potential savings and payback period.

Contact US Solar Supplier for a free consultation to match your needs with the most efficient solar inverter!