There are four main types of solar inverter used in residential grid-connect solar power systems: string inverters, microinverters, power optimizers with string inverter, and hybrid inverters.

Each type of inverters has its pluses and minuses.  Choosing the right solar inverter for your home will depend on several factors including:

• Whether your roof is partially shaded
• Whether the roof layout is straightforward or complex (i.e., gabled, multiple orientations)
• Whether you plan to add a battery
• Whether panel-level monitoring is important for you
• Safety factors
• Your budget

On this blog:

• What is the purpose of a solar inverter?
• Why it’s important to choose the right type of solar inverter for your property
• String inverters: pros and cons
• Microinverters: pros and cons
• Power optimizers and string inverters: pros and cons
• Hybrid solar inverters: pros and cons

What is the purpose of a solar inverter?

The purpose of a solar inverter is to convert DC (direct current) electricity from solar panels into usable AC (alternating current) electricity for your home or the grid.

Why it’s important to choose the right type of solar inverter for your property

It may be surprising to learn that the solar inverter you choose has the biggest impact on the overall power output of your solar system – not the solar panels.  That’s because the solar inverter is essentially the brains of your solar power system and choosing the right type of inverter for your property can significantly increase overall power output.

And when it comes to adding a battery to your solar system, the choice of inverter becomes even more critical.  That’s because different types of batteries work in different ways, depending on the type of inverter you choose.  Some are a lot more efficient than others.  Knowing this information in advance will help you choose the type of inverter that’s going to produce the most power for your home – which is the end goal after all!

String inverters: pros and cons

With a string inverter system, DC electricity from the solar panels travels via DC wiring across your roof to a string inverter which converts the DC electricity to AC for use in the home.

The reason why it’s called a string inverter is because the solar panels are connected in a string – and each string connects into the inverter.

With a string inverter solar system, there’s normally two strings of solar panels (i.e., two rows), with an equal number of panels on each row.

String inverters are the most common type of solar inverter in Australia.  They are tried and tested technology and a good choice for homes with straightforward sunny roofs.

Pros

• Proven technology
• More cost effective than other inverter types
• Widespread availability; many excellent quality brands
• A great choice if you have a sunny roof with a straightforward layout

Cons

• If one solar panel on a string is under performing (because of dirt, shading etc.), it will bring down the performance of all panels on that string.
• Potential safety issue: high DC voltage on your roof. That’s why choosing a quality solar installer who doesn’t take shortcuts with the DC wiring is super important!
• Power generation can only be monitored at overall system level (not panel-level).
• Not possible to proactively identify faults with individual panels. (This makes it harder to make a warranty claim for a panel.)
• Works best with AC-coupled batteries (that have their own built-in battery inverter but are less efficient than DC-coupled batteries)

Microinverters: pros and cons

Microinverters are small inverters that are about the size of a paperback book.  They are attached to the back of each solar panel and convert DC power to AC power at panel-level.

With a microinverter system there’s no need for a central string inverter on your wall; the inverters are all hidden away under your solar panels.

One of the biggest benefits of microinverters is that they optimize the power at panel-level.  This means that if there’s any shading or dirt on a panel, none of the other panels will be affected.

Pros

• Proven technology; 20+ years
• Ideal for roofs with partial shading
• Suitable for complex roof layouts
• Even if one solar is dirty or shaded, the other panels will continue to work at maximum efficiency
• Monitoring will show the power output for each individual solar panel. This means you can easily spot any underperforming panels and get them fixed.
• Improved safety; no DC wiring across your roof

Cons

• Price (most expensive type of inverter)
• Costly to repair (as inverters are located on the roof)
• Prone to overheating, particularly on black roofs in the middle of summer (this can reduce power output and shorten the life of the microinverters)
• Works best with AC-coupled batteries (that have their own built-in battery inverter but are less efficient than DC-coupled batteries)

Power optimizers and string inverters: pros and cons

Power optimizers are little black boxes that are fitted to the back of each solar panel.  They condition DC power from each panel (by fixing the voltage) and send it to the string inverter which converts it to AC power.

Like microinverters, power optimizers enable the output of individual solar panels to remain unaffected if another panel is underperforming.  But because they still include a string inverter, less parts are involved which makes power optimizers a more cost-effective solution than microinverters.

Pros

• Well suited to partially shaded roofs
• Good for roofs with complex layouts
• Lower price than microinverters
• Power generation is optimized at panel-level = more power for your home
• Extremely safe – built-in DC safety features
• Greater choice of batteries (both AC and DC-coupled)

Cons

• More expensive than conventional string inverters
• Warranty mismatch – power optimizers typically have a 25-year warranty; string inverters have 10-15 years but this can be extended to 25 years

Hybrid solar inverters: pros and cons

Hybrid solar inverters are an all-in-one inverter that carry out the job of both a solar inverter and a battery inverter.  If you’re thinking about going solar plus battery storage, a hybrid inverter may well be the best choice for your home.

What a hybrid inverter does is impressive. It converts DC power from the panels to AC power for the home and the grid. It also manages the flow of DC power to and from the battery.

A hybrid solar inverter is the simplest system for converting DC power to AC power for your home – and it’s the most efficient when combined with battery storage.

Pros

• Extremely efficient, particularly when combined with battery storage
• Lower overall system cost (for solar + battery storage) as there is only one inverter
• Lower maintenance costs – only one inverter to maintain
• Compatible with DC-coupled batteries which offer higher levels of efficiency than AC-coupled batteries
• Great for future-proofing – add up to 200 per cent more solar panels than the capacity of the hybrid inverter

Cons

• Less choice (compared to string inverters)
• Only compatible with DC-coupled batteries (but this is a positive point as DC-coupled batteries are more efficient)

Request a quote

With solar inverters there’s no definite ‘right and wrong’ type of inverter.  It all depends on your property, your roof, the amount of sunlight, whether you want battery storage and your budget.

That’s why at SolarRun we take the time to find out exactly what you want from solar, assess your property thoroughly and provide a fully customized solution that meets your needs.

Get in touch with us for expert advice and a quote!