Micro Inverter vs. Power Optimizer, How do I choose?

Deciding on the right inverter for your solar system can be a daunting and confusing decision. What is the difference between micro inverters and power optimizers anyway? What does that even mean? We are here to help you decide which is the right inverter for your solar system, and once you understand the differences, the choice will be easy!

Every solar inverter’s primary function in life is to convert the DC electricity produced by your solar panels into AC electricity for safe use in your home.

With advances in technology over the last few years, it is now possible to install inverters suitable for a variety of different installation. Each type of inverter comes with its own benefits and disadvantages. Let’s take a look!

Solar Edge Optimizer how it works

Above Illustration: Example Power Optimizer with String Inverter See the SolarEdge home page for more information on Power Optimizers and String Inverters

String Inverter with Power Optimizer

A solar system designed using a string inverter has a series of solar panels strung together that feeds into the one large central inverter. Traditionally, because each solar panel is connected to the next, if one panel is under performing it would drag down the efficiency of the rest of the panels; a bit like old school fairy lights!

This design is not ideal for solar installations that might have some panels covered by shade or has panels facing in opposite directions. If one solar panel is performing at 50% capacity, so will all the others.

Power optimizers solve this problem. With each solar panel containing an integrated power optimizer, the DC electricity is stabilized before travelling to the central string inverter, preventing panels with lower outputs affecting the whole system. It doesn’t matter if one panel is shaded or is installed facing a different direction; one poor performing panel can’t drag its neighbors down anymore!

Power optimizers also give you the ability to monitor each solar panel independently so that any system errors can be identified and rectified quickly; saving you time and money trying to troubleshoot why your system is not performing to its maximum capacity.

Although solar systems installed using string inverters with power optimizers are slightly cheaper than micro inverters, they do not offer much flexibility for future expansion.

String inverters are not capable of safely receiving more DC electricity than they are rated for, so trying to expand your solar system to 5kw on a 3kw inverter is not going to happen! One option is to install a larger size inverter during your initial installation to accommodate for any future expansion. However, this is an additional extra expense that will be wasted if you do not end up expanding your system.

Micro Inverter Enphase how it works

Above Image: Example of Micro-Inverter See the Enphase homepage for more information on Micro Inverters

Micro Inverter

Micro inverters offer flexibility and efficiency when designing and installing your solar system. Each solar panel contains a micro inverter, rather than a single, large string inverter, so the conversion of DC to AC electricity happens right on your roof.  There is no need for the DC electricity to travel to a larger central inverter taking up space on your garage wall!

Just like power optimizers, micro inverters allow you to monitor individual panel output, and every solar panel has the ability to function independently of each other. If your roof receives shade during part of the day, or your solar panels will need to be installed in different locations on your roof, then micro inverters will allow each panel to operate to its full potential without being impacted by poorer performing panels. You could have one panel here, another over there; it doesn’t matter!

The major benefit of micro inverters over power optimizers is the flexibility to increase the size of your solar system after your initial installation. It is much more cost effective to expand your solar system using micro inverters as the system output is not restricted by the size of the inverter like in a string inverter system. So, if your kids suddenly decide to move back home, and you have the roof space available, you can add more solar panels to cover the extra electricity they undoubtedly consume!

The only real disadvantage of micro inverters is they are slightly more expensive than other types of solar inverters, so it is important to calculate whether the option of future expansion is worth the extra initial cost. If expanding your system at a later date might be an option for you, the initial additional cost up front vs. the cost of upgrading inverters and cabling down the track is definitely worthwhile.

Enphase SolarEdge vs

 Summary

Both micro inverters and power optimizers offer the same benefits when it comes to maximizing your solar system’s potential output.

They both ensure each solar panel works independently to one other, so installations that have some panels shaded or facing in different directions do not impact on the performance of the rest of the system. They both allow flexible installation options and monitoring of the solar system’s output at panel level to ensure any issues are identified quickly and cost effectively.

The real difference is the initial cost vs. potential future expansion.

If you do not want a large central inverter taking up space on your wall and you have the roof space for future expansion, micro inverters are the way to go.

If your roof space is at maximum capacity with the current proposed installation and you have the room to house a large central inverter, then a string inverter with power optimizers is the right choice for you!

For more information go to oneclicksolar.com and see our FAQ page

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