Do I Need a Power Optimiser?

Updated: November 22, 2021

A power optimiser is an electrical device added to a solar system to improve its efficiency. Power optimisers are considered to be MLPE (module-level power electronics). The condition and fix the voltage of the DC energy then sends it to an inverter where it is converted to AC energy. Power optimisers are usually paired with centralised string inverters as they cannot invert energy on their own.

A power optimiser increases the efficiency of electricity generation of your solar system if your roof is complicated or prone to partial shading during the day. It also allows you to monitor the performance of individual modules for easy troubleshooting, repair, and maintenance.

So, if your modules are prone to mismatch loss due to degradation, partial shading, or manufacturing tolerance, a power optimiser will eliminate these issues and boost energy production.

Do I need a power optimiser

There are several reasons to use power optimisers. These include:

  • When you want to monitor the performance of your panels, power optimisers will help you know how individual panels are performing. This allows for quick troubleshooting and repair of specific panels.
  • If your panels are facing different directions due to a complicated roof, a power optimiser ensures maximum performance of each panel whenever they are hit by sunlight.
  • Power optimisers also optimise power productions for roofs that experience marginal shading during the day.

With a power optimiser, your solar system will be more efficient and durable.

How do power optimisers work?

Typically, the sun hits PV solar panels which then create DC electricity that is sent to central string inverters for conversion into AC energy. However, complicated installations and roofs with marginal shading issues may reduce the power output of the panels. Power optimisers use the maximum power point tracking (MPPT) technology to improve the efficiency of each solar panel.

Power optimisers are usually installed at the rear side of individual solar panels and turn them into smart modules. These devices track the peak power output of the panels in real time then regulate or condition the voltage before sending the electricity to the central inverter.

This optimises the performance of individual solar panels in your system regardless of their orientation, damage or shade.

Which power optimiser do I need?

Before you choose a power optimiser, you should consider the factors below.

Efficiency

Power optimisers have different efficiencies, just like solar panels. The efficiency of a solar optimiser is measured by how much energy is lost when energy is being converted from DC to AC. Optimisers with higher efficiencies are the best to buy as they will offer more solar energy production.

Price

Power optimisers are not as expensive as solar panels, but it is essential to know how much they cost. Usually, power optimisers with longer warranties and higher efficiencies will be costlier than optimisers with lower efficiencies and shorter warranties. The device you choose will depend on your budget and preference.

Warranty

Most manufacturers offer a 25-year warranty for their power optimisers. This warranty protects consumers in case of manufacturing defects. Also, string inverters paired with the optimisers come with a separate warranty that may last between 5-15 years. Ensure you read the warranty agreement of several products before purchasing them.

Size

Solar optimisers and inverters are available in different sizes designed for different electricity voltages. Generally, larger optimisers and inverters will be costlier than smaller ones. Ensure the optimiser and inverter you buy suits your system.

Do I need to use a Solar Inverter with a power optimiser?

Yes, you should use a solar inverter with a power optimiser to make sure all the DC energy produced by each panel becomes converted into AC energy. The power optimisers track the maximum power output of the panels in real-time. It then conditions and soothes the DC electricity before sending it to the solar inverter. This ensures the inverter processes more electricity, which increases the power output of your solar system.

Are power optimisers safe to use?

Absolutely yes! Power optimisers come with a safety voltage function designed to automatically reduce the DC voltage of the solar panels to a safe level (usually 1VDC) in case of the following scenarios:

  • When the grid power or inverter shuts down
  • The optimiser and modules become disconnected
  • When the system becomes faulty
  • When the inverter or safety switches are turned off

Your power optimisers can also be grounded depending on city regulations or racking components.

Does a power optimiser work on days with bad weather?

Yes, power optimisers can still work during bad weather. These devices are designed to function in harsh weather conditions, but their efficiency becomes lower than days with favourable weather. More so, with the MPPT tracking technology, your solar system may have a better performance during bad weather than systems without microinverters or solar optimisers.

If a single panel is completely shaded, the power optimiser for that panel may shut down temporarily. This will, however, not affect the performance of the other power optimisers.

Does a power optimiser work on days with bad weather rainy day

What are the advantages and disadvantages of power optimisers?

Power optimisers have several advantages and disadvantages, as outlined below:

Advantages

Increased efficiency in partially shaded panels

Solar panels that are partially shaded or installed on roofs with several angles tend to have a lower DC output. A power optimiser increases the output of individual panels that experience shading or do not get direct sunlight. This increases the overall power output of your system.

Monitors individual panels

Solar optimisers are MLPE that collect and feed solar energy production data such as peak efficiency and output voltage from each panel to the cloud. You can then get updates on the performance of individual solar panels in real-time.

Smaller inverter size

Voltage cleaning and tracking occur at the individual panel level, which means the inverter will be smaller. This makes power optimisers an excellent choice for homes with limited installation space.

Disadvantages

High installation cost

Power optimisers are installed on each solar panel, which means every solar module will have its own optimiser. This increases the installation cost compared to the traditional string inverters.

Different warranties

The standard warranty for power optimisers is 25 years, but the inverters paired with them have a warranty of 5-15years. This can be frustrating as you may be forced to replace your inverter before your solar panels.

Limited inverters

Solar inverters are a new technology that is fast becoming popular for commercial and residential solar systems. However, finding a genuine inverter is quite daunting. SolarEdge is by far the only reliable manufacturer for inverters, and you cannot use other brands with their solar optimisers. This limits the options for customers that may want to explore other options.

Are power optimisers worth it?

Yes, power optimisers are a worthy investment for both commercial and residential solar arrays. If your site or roof experiences shading during the day, or you want to increase the efficiency of your solar system, power optimisers are an excellent option.

DIY vs. hiring a Professional

Installing power optimisers is not as complicated as most people think. If your solar panels are already installed, you can affix the inverter to the backside of the panel without a hassle. However, you must follow the installation guidelines carefully.

While DIY installations are cost-effective, they are prone to mistakes, especially if you are a beginner. It is better to let professionals do the installations for seamless results.

Do It Yourself

Below are the pros and cons of DIY installations.

Pros

  • They are cost-effective as you will not pay for labour
  • You will get an opportunity to hone your skills
  • You get to decide which power optimisers to use and where to install the inverter
  • You will feel fulfilled and satisfied after the project

Cons

  • Higher risk of roof damage and leakages
  • Physical danger due to inexperience
  • It is time-consuming
  • DIY is costly in the long run due to damages during the installation

Hiring a Professional

Some of the pros and cons of professional installations include:

Pros

  • Professionals are experienced to install power optimisers
  • Low risk of physical danger and damages to the modules, roof and solar optimiser
  • Pros will complete the installation within the timeline
  • You will get warranties for the solar optimisers and inverter

Cons

  • Professional installations are quite costly
  • You may not be sure of the results

FAQ's

Both power optimisers and microinverters are excellent options if you are looking to increase the efficiency of your solar panels. However, microinverters do cost more than power optimizers.

Besides, the cost per watt for power optimizers decreases as the systems get larger. This is because you can use one central inverter when you increase your system size, unlike microinverters, where you have to buy a new microinverter whenever you add a new solar panel.

A solar power optimiser costs around $70 to $100, depending on the size and type. The installation cost will depend on your location and the number of power optimisers you will need for your system.

SolarEdge is one of the best power optimisers in the market. This power optimiser increases the energy output of solar systems on complicated roofs and roofs prone to marginal shading during the day. The SolarEdge power optimiser individually tracks each panel’s MPPT (maximum power point) to make sure it works efficiently.

Ben McInerney head shotAuthor: Ben McInerney is a renewable energy enthusiast with the goal of helping more Australians understand solar systems to make the best choice before they purchase. Having an accredited solar installer in the family helps give Ben access to the correct information, which allows him to break it down and make it easily understandable to the average homeowner.