Beginners Guide to Solar Inverters

12 Nov

Beginners Guide to Solar Inverters

In this blog we look at the different types of solar inverters available: string inverters, hybrid inverters and micro-inverters. We will also look at solar optimisers. Although not an inverter, they are sometimes used in conjunction with a string inverter in certain situations.

A solar inverter is crucial to every solar system. At its core it does a basic job converting DC electricity generated by your solar panels into AC electricity to power your home.Each type of inverter offers different advantages and disadvantages. So here is our easy-to-understand solar inverter guide.

Link to CEC approved inverters
https://cleanenergycouncil.org.au/industry-programs/products-program/inverters

String Inverters

String inverters are the most installed type of inverter in Australia for residential and commercial solar systems. With a string inverter the solar panels are connected in a series or “string”. The DC power the panels produce is sent to the inverter to convert into AC power for use in the home.

Most string inverters will support two separate strings of panels. Each panel in a string must face in the same direction. For example one string my face north and the second string may face east.

String Inverter Advantages

Cost effective string inverters are the cheaper then other types of inverters

Efficiency: Solar systems with a string inverter achieve a higher efficiency when the solar panels are receiving uniform sunlight.

Ease of Installation: String inverter systems are easier and more economical to install with fewer components involved especially when compared with micro inverters.

Simple Design: String inverters enable straight forward and simple solar system design which is adequate for most systems.

String Inverter Disadvantages

Effected by Shading: In a string system each panels output is limited to the output of the lowest performing panel. This means that is a panel is effected by shade it will reduce the output of the other panels in the string.

Limited Design Flexibility: All the panels in a string all need to face the same direction for optimum power production.

Hybrid Inverters

A hybrid inverter is basically two inverters in one. They combined the functionality of a solar inverter with a battery inverter allowing the easy integration of a solar battery into a solar system. This enables the customer to store excess energy generated by the panels during the day for use at night or during greed power outages.

If you are buying a solar system and the battery together your solar installer will typically recommend a hybrid inverter for the system.

Hybrid Inverter Advantages

Battery Compatibility: supports both solar power and battery energy storage. This enables better energy management for the customer.

Energy Independence: with a hybrid inverter and a battery you can use the stored energy at night or during non sunny hours increasing your energy independence and reducing your power bills significantly.

Green support: good hybrid inverters can switch between grid power and solar power as needed to optimise electricity usage.

Hybrid Inverter Disadvantages

Higher cost: hybrid inverters are more expensive then traditional string inverters due to their increased functionality.

Less mature technology: Hybrid inverter technology is still developing. So your solar provider should recommend using a leading hybrid inverter such as Sun Grow.

Micro Inverters

Micro inverters are a small inverter and one is attached to every solar panel in the solar system. So instead of having a central inverter each panel has its own small inverter converting DC power produced by the panel to AC power for the home. However, there is also a need for a controller to manage all the micro inverters in the system.

In our experience we see micro inverters overhyped by some installers for their ability to outperform standard string inverters. In situations where customers are facing serious shading issues they can be good option. If you are not facing shading issues, then the performance advantage is not enough out way the extra cost.

Micro Inverter Advantages

Optimised Performance: since each panel operates independently with the micro inverter shaving or malfunction in one panel does not affect the performance of the other panels.

Design flexibility: On complex roofs micro inverters allow solar panels to be installed at different orientations and angles making them ideal in this situation.

Increased Power Yield with Shading: micro inverters generally produce more energy especially in conditions of partial shading.

Micro Inverter Disadvantages

High Cost: micro inverters are more expensive than string inverters both in terms of equipment and installation costs.

Complexity: each micro inverter contains up to 250 individual components and this equates to more potential points of failure. This is worth bearing in mind considering the temperature on the roof can reach up to 65°C on a hot summer’s day in Australia.

Power Optimisers

Yes, that’s right a power optimiser is not an inverter. However they are sometimes combined with string inverters, and similar to micro inverters, they are installed onto the panel. Instead of converting DC produced by the panel to AC they optimise the DC output of each panel and send it to a central string inverter for conversion into AC power for the home.

Unlike micro inverters you do not have to put a power optimiser on every panel in the system. You can choose to put an optimizer only on the panels that maybe affected by shade.

Power Optimiser Advantages

Improved Performance in Shaded Conditions: Power optimisers minimise the effect of shading or under performance of individual panels.
Higher Efficiency: Optimisers can offer better energy yield per panel then string inverters.

Cost Efficiency Compared to Microinverters: Power optimisers are cheaper than micro inverters providing a middle ground in terms of cost and performance.

Power Optimiser Disadvantages

Additional Components: More components compared to string inverter system increase the complexity of the system and also potential points of failure.

Higher Cost: While not as expensive is micro inverters, power optimiser systems are still more costly then string inverter systems.

Each solar inverter type has its own strengths and weaknesses. A solar specialist such as SolarBright will design a solar system to suit your exact needs with the appropriate Clean Energy Council Approved inverter included. By wary if someone is pushing a micro-inverter based system when you do not have shading issues, we often come across that.

They can often be around $8000 for a 6.6kW solar system only – almost double the price of a string inverter system! Add another couple of thousand to that and you can get a decent solar AND battery system. If you are seeking no nonsense solar advice call SolarBright today.

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