The Solar Power Inverter
One of the key components of a residential solar energy system is the solar power inverter.
Home solar power systems can be used to provide power for many standard electrical devices and household appliances. But in order to provide this power, these systems require solar inverters.
What is a Solar Inverter
For more information about the basics of electricity, take a look at our page on.
The purpose of an inverter is to change Direct Current (DC) electricity into Alternating Current (AC) electricity. It also will increase the voltage of the AC electricity to 120 Volts AC (if you’re in the United States) or 240 Volts AC (if you’re in most other parts of the world).
But why is a solar power inverter needed in the first place?
Well, a solar inverter is needed because the electricity generated by your solar panels is DC electricity. In order to use the generated solar power with your electrical devices and household appliances, it needs to be converted to the standard voltage AC electricity for your region.
Types of Solar Inverters
Solar inverters can be categorized by the type of solar power system they are used with.
A Grid Tie Inverter is used with a grid-tied PV system. This type of solar power inverter takes the DC electricity generated by the solar panels and converts it to AC electricity directly. It channels the AC electricity to your home’s breaker panel where it is either used by your household loads or, if you are signed up for net-metering, sends it to the utility grid.
An Off Grid Inverter is used with a stand-alone or off-grid solar system. An off-grid solar system typically uses batteries to store the DC electricity generated by your solar panels. The inverter converts the DC electricity from the batteries into AC electricity for use in your home.
An On/Off Grid Inverter is used with a grid-tied PV system with battery backup. This type of inverter allows you to connect your home to the utility grid and use power from a battery bank. Unlike a pure grid tie inverter, this type of inverter is able to continue transferring power to your home when the utility has a blackout. During a blackout, a grid tie inverter will not be operational.
Solar Power Inverter Considerations
Three factors homeowners should consider when evaluating inverters are.
Power Quality
The quality of the AC electricity generated by your inverter is important for household use. For most home solar power systems, you will want to use what’s known as a pure sine wave inverter. This is also known as a true sine wave inverter.
This is considered clean power and is suitable for all household electrical applications such as computers, televisions, and microwaves. It is the same type of power provided by the utility companies.
Some solar power inverters generate dirty power. This type of inverter converts the DC electricity into AC electricity that is in the form of a stepped square wave and is known as a modified sine wave inverter.
The AC electricity generated by this type of inverter can have a noticeable impact on your electrical equipment’s performance. For example, audio speakers will buzz, microwaves will take longer to heat food, and television and computer monitors will display rolling lines.
Power Rating
The amount of power the inverter can handle is known as it’s power rating. Two critical power ratings you will need to understand for your inverter are it’s continuous rating and it’s surge rating.
An inverter’s capacity refers to it’s continuous rating. This is the amount of power it can supply continuously. So when you see a 4000 W inverter, this is referring to it’s continuous rating. The inverter you choose should have a continuous rating that is about 25% higher than the maximum power you will need to deliver to your household loads.
Household loads such as refrigerators and washing machines may require a short-term boost in power to get started. The amount of power can be 2 to 3 times the normal operating power, so make sure to check that your inverter’s surge rating can handle that amount of power for a few seconds.
Efficiency
Inverter efficiency is another factor to consider. An inverter’s efficiency indicates how much of the input DC power it converts into AC power. This will never be 100% because the inverter uses some of the input DC power itself, generally around 10-25 W.
The efficiency of an inverter depends on the power output level it is operating at. At different power levels, it will be operating at different efficiencies.
Inverters operate at maximum efficiency at a power level know as it’s peak efficiency point. This is generally at around 20-30 percent of it’s maximum power rating. So if you have a 4000 W inverter, it’s peak efficiency point will be between 800 and 1200 W.
An inverter’s efficiency is shown in an efficiency curve. What you will see is that the inverter’s efficiency will increase sharply until it reaches it’s peak efficiency point. It will then remain close to level, decreasing slightly as it approaches it’s rated power output.
Don’t stay focused on peak efficiency. It’s important, but you also have to consider the whole efficiency curve. Ideally, your electricity use should be at or above your inverter’s peak efficiency point. By choosing a solar power inverter that matches your electricity use, you will be able to better utilize the solar electricity you generate.
How long do residential solar inverters last?
Multiple factors affect the productive lifespan of a residential solar inverter. In Part 2 of our series, we look at solar inverters.
Image: Wikimedia Commons
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In the first part of this series, pv magazine reviewed the productive lifespan of solar panels. which are quite resilient. In this part, we examine residential solar inverters in their various forms, how long they last, and how resilient they are.
The inverter, a device that converts the DC power produced by solar panels into usable AC power, can come in a few different configurations.
The two main types of inverters in residential applications are string inverters and microinverters. In some applications, string inverters are equipped with module-level power electronics (MLPE) called DC optimizers. Microinverters and DC optimizers are generally used for roofs with shading conditions or sub-optimal orientation (not south-facing).
The technology ensures that each panel produces its max capability real-time and isn’t limited to the weakest link in the chain or “string.” String inverters are subject to the “Christmas light” effect where if one panel is not performing or is shaded, the rest of the panels connected in series will be limited to that panel’s production level.
Some string inverters are equipped with a bypass diode, a technology that prevents the “Christmas light” effect from taking place altogether, shown here by Fronius.
In applications where the roof has a preferable azimuth (orientation to the sun) and little no shading issues, a string inverter can be a good solution.
In a string inverter, there is generally less complicated wiring and a centralized location for easier repairs by solar technicians. Typically they are less expensive, said Solar Reviews. It said that inverters can typically cost 10-20% of the total solar panel installation, so choosing the right one is important.
How long do they last?
While solar panels can last 25 to 30 years or more, inverters generally have a shorter life, due to more rapidly aging components. A common source of failure in inverters is the electro-mechanical wear on the capacitor in the inverter. The electrolyte capacitors have a shorter lifetime and age faster than dry components, said Solar Harmonics.
EnergySage said that a typical centralized residential string inverter will last about 10-15 years, and thus will need to be replaced at some point during the panels’ life.
String inverters generally have standard warranties ranging from 5-10 years, many with the option to extend to 20 years. Some solar contracts include free maintenance and monitoring through the term of the contract, so it is wise to evaluate this when selecting inverters.
Microinverters have a longer life, EnergySage said they can often last 25 years, nearly as long as their panel counterparts. Usually, these inverters have a 20–25-year standard warranty included. It should be noted that while microinverters have a long warranty, they are still a relatively new technology from the past ten years or so, and it remains to be seen if the equipment will fulfill its 20 year promise.
The same goes for DC optimizers, which are typically paired with a centralized string inverter. These components last for 20-25 years and have a warranty to match that time period.
Failures
A study by kWh Analytics found that 80% of solar array failures occur at the inverter level. There are numerous causes of this.
According to Fallon Solutions. one cause is grid faults. High or low voltage due to grid fault can cause the inverter to stop working, and circuit breakers or fuses can be activated to protect the inverter from high-voltage failure.
Sometimes failure can occur at the MLPE level, where the components of power optimizers are exposed to higher temperatures on the roof. If reduced production is being experienced, it could be a fault in the MLPE.
Installation must be done properly as well. As a rule of thumb, Fallon recommended that the solar panel capacity should be up to 133% of the inverter capacity. If the panels are not properly matched to a right-size inverter, they will not perform efficiently.
Maintenance
To keep an inverter running more efficiently for a longer period, Those Solar Guys recommended choosing a cool, dry place with lots of circulating fresh air. It also suggested avoiding installing in areas with direct sunlight, though specific brands of outdoor inverters are designed to withstand more sunlight than others. And, in multi-inverter installations, it is important to be sure there is proper clearance between each inverter, so that there isn’t heat transfer between inverters.
Those Solar Guys said it is best practice to inspect the outside of the inverter (if it is accessible) quarterly, making sure there are no physical signs of damage, and all vents and cooling fins are free from dirt and dust.
It is also recommended to schedule an inspection through a licensed solar installer every five years. These standups typically cost 200-300, though some solar contracts have free maintenance and monitoring for 20-25 years. During the checkup, the inspector should check inside the inverter for signs of corrosion, damage, or pests.
In the next installment of the series, pv magazine will examine the life of residential battery energy storage applications.
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Ryan Kennedy
Ryan joined pv magazine in 2021, bringing experience from a top residential solar installer, and a U. S.
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14 Комментарии и мнения владельцев
Here is a link to our collection of “solar 101” articles that offer a good introduction to residential solar. https://pv-magazine-usa.com/?s=solar101
What caught my eye in the article was what appears to be a Sunny Island inverter photo. I use a pair of these, though I don’t leave them out in the weather. I hope they will last a good, long time. Your article really did not cover inverters that run from solar-charged batteries. Has the term Solar Inverter come to apply only to those that are directly connected to solar modules? Are we calling inverters that have batteries in the system something else? You say that the string and microinverters are predominant. I can see that, but it is a shame. They are great where there is true net metering, but more and more power companies are stacking the deck against home solar. I see hybrid and Zero Export Grid Tie (ZEGT) as the only realistic options in many areas. Much of my home is on off-grid style power and the rest is on battery-buffered ZEGT. The power company does not get involved in any special metering, connection fees or complex accounting. Any way, I was curious as to how long I should I expect MY Sunny Islands to last. I suspect the answer will be the same, which is, “as long as the electrolytics last.” Beyond that, the questions are how easy will the electrolytics be to change and how much havoc will be created when they fail. An inverter which just gets a little erratic and has bolt-on capacitors would be a great design. One that causes massive chain-reaction failure of all the Flame Emitting Transistors (FETs) and has capacitors soldered in an inaccessible location would probably be a write-off. Electrolytic caps last longer when they don’t get hot, as you pointed out. My inverters are outdoors in a fan-cooled cabinet, which is probably better than the one in the photo with direct sunlight heating. My backup inverter is in my air conditioned control room, which is probably where the SMA units should have gone for maximum life. I can’t imagine that the caps in a microinverter behind a hot solar panel would last as long as a string inverter in the shade of the eaves.
Hi Neal, if you look closely, it is actually a SunnyBoy not Sunny Island, but failure mechanisms are the same. The SunnyIsland just adds more components as the inverter operates bi-directionally. Good job putting it in a fan-cooled location. Keep all of your fan grilles clean from dust as the author suggests. Electrolytics are a lot cheaper than film capacitors, which are more popular in micro-inverters, as they are rated at lower voltage and capacitance, because they support only about 1/10th of the power per unit. A lot of printed circuit boards fail because of temperature cycling, corrosion (e.g. high humidity – and freeze). Memory failure is another big problem as it controls the operation of output FETs (actually IGBTs in most), thousands of times per second. Those IGBTs fail most likely on a clear sunny cold winter day when the inverter is cold and the sun comes up quickly at full insolation and output power, leading to internal thermal expansion at different rates, cracking the chip substrates. We just returned from life-cycle testing a bunch of vintage inverters at Sandia National Labs, most of them with over 50,000 hours on the clock. While one SunnyBoy failed the first time we pushed up ambient temperature beyond spec, another unit was playing possum many days in a row, tripping a dozens of times at cold temperatures (when capacitors cause for more noise due increased internal resistance), but came back the next day, for a whole week straight. It surprisingly survived even 95 deg C measured heatsink temperature at increasing power output beyond spec. Inverter reliability depends on many factors under and outside of the control of the manufacturer, hence we are developing an “Energy Cardio Graph” solution predicting failure of big utility-scale inverters in the field while operating. Those who fail more frequency then string inverters, and cause a lot more damage (having a few Megawatts going sideways).
My family has two solar arrays, the first was built with 4 and then 2 more panels and micro inverters. The second has 24 panels and an SMA Sunny Boy 5000. The Sunny Boy has shrugged off 2 lightning power surges by blowing a small fuse inside. First time, my solar guy came out, fixed it and I paid him. Didn’t buy extra fuse(s). Second time, jumped on Amazon after taking a multi meter and finding the same fuse blown. Two days later, installed fuse and all is well. Little array original 4 inverters built like a tank. About 9 years, no issues. The 2 added micro inverters have a nifty little light that’s either red or green when the sun’s out. I have had a total of 5 replacements on those, and they were installed more than a year after the first 4. I don’t claim this will be anyone’s outcome but mine, but I know which ones have performed and which have a somewhat lower resiliency.
Has anyone had a problem w glare issue from panels ? Our neighbors across a small waterway find their walls lighting up. It happened April 3 rd, lasted a month and has come back 6 mos later. Obviously seasonal position of sun. The ‘glare’ starts at one side and in the course of an hour moves across the panels. Our solar company seems dumbfounded and we need to solve or our HOA may have us remove solar panels.
Either adjust the angle of the panels and or plant a shade bush between you and them. Can’t change the sun!
Given government mandates in green energy it is unlikely your HOA can force removal of your solar panels particularly since I presume you submitted your installation plans to the HOA prior to obtaining city permits. Check your local state laws and consult a knowledgeable attorney.
I would call companies that manufacture various anti-reflective coatings and test them out; some coatings may even have the potential to slightly increase absorbed light, improving panel efficiency. A quick google search led me to: https://sinovoltaics.com/learning-center/solar-cells/anti-reflective-coating-for-solar-panels/ https://www.pveducation.org/pvcdrom/design-of-silicon-cells/anti-reflection-coatings Some other sources suggested that anti-reflective coatings (AR) like this can improve panel efficiency roughly 1%.
I have been living off-grid for 21 years, using a Trace 4024 inverter, which is in the cellar along with all the other components of the system other than the (unshaded, tilt adjustable) arrays. It is not clear to me what advantage micro- or string-inverters have for my application, and outside placement seems highly detrimental to lifetime. In the next year or so I intend to at least double my 2100W array (still performing very well) and replace the inverter with a 240 split-phase and higher-output inverter, still off-grid. I’d really be interested in an evaluation of these off-grid products, and I’d like to know if any of the current off-grid inverters will work for 20 years with utter reliability like the Trace. Yes, grid-tie is common but some of us tough geezers are still alive (and so are our DIY systems!)
When considering the life expectancy of string solar inverters, the average lifetime is less than 15 years, 10 years less than the average lifecycle of solar panels. However, it is possible, with appropriate maintenance checkups, for inverters to last up to 20 years. You can find an informative infogrphic about solar inverters here: https://www.promoandprintco.com.au/print/
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What is a Solar Inverter and How Does It Work?
Solar inverters are an essential part of any solar power system. They convert the direct current (DC) power produced by photovoltaic solar panels into alternating current (AC) electricity that powers the appliances and devices in most homes and businesses.
Choosing the correct solar inverter can be confusing, especially for beginners. This article explains solar inverter basics, including their functions, types, and applications.
We’ll walk you through the alternatives and recommend the leading solar inverter options on the market to help make your decision easy.
What is a Solar Inverter?
A solar inverter is essential to any solar power system. It converts the direct current (DC) electricity your photovoltaic (PV) solar panels produce into alternating current (AC) electricity, the type of electricity used in your home. An inverter is a balance of system component built into many solar generators or installed between your solar panels and your home’s electrical panel.
Inverters also have several other essential functions, such as monitoring and optimizing the performance of your solar panels. In off-grid solar power systems, the energy converted into AC electricity by an inverter is stored in a solar battery. Without a solar inverter, the electricity produced by your solar panels would be unusable.
Solar inverters are a vital component of any solar power system. Without one, you can’t use the clean, renewable energy your panels produce to power your home.
What Do Inverters Do?
Inverters are devices that convert direct current (DC) electricity into alternating current (AC) electricity. The difference between DC vs. AC electricity comes down to a difference in conversion to higher or lower voltages, and inverters assist with that.
Inverters have a wide range of applications in solar power, battery backup, and renewable energy systems. Besides conversion, they optimize electrical system performance.
In solar power systems, inverters convert DC electricity into AC electricity for homes and businesses. Some solar systems include built-in inverters, such as the EcoFlow Solar Generators. Others require purchasing an inverter separately.
When used in battery backup systems, they allow for storing excess electricity in batteries during power outages or when renewable energy sources are unavailable.
In non-solar renewable energy systems, inverters convert electricity from wind turbines and hydroelectric generators into usable AC electricity. Inverters are essential in converting and distributing electricity.
Input and Output
Solar inverters have two primary input and output connections: the DC input from the photovoltaic panels and the AC output to your solar battery (or home electrical panel for grid-tied solar systems).
Types of Solar Inverters
The best type of solar inverter depends on how you’ve wired the panels to each other and your home.
String Inverters
String inverters are the original solar inverter technology and often the cheapest option. They convert the DC power from an entire string of panels into AC power for your home.
Shade — such as from trees obscuring part of your roof — is the biggest downfall with string inverters. When you have panels wired in strings, if one panel isn’t receiving sunlight (or is damaged), it will reduce the output of the entire array. Additionally, your solar power system won’t function if a string inverter goes down.
Micro Inverters
Micro inverters are a more recent technology. Smaller inverters attached to each solar panel convert the DC power to AC electricity before sending it to the balance of system.
According to researchers at the University of Virginia, a system that uses micro inverters is 27% more efficient than string inverters. It works better for roofs with varying angles or shaded spots, as the power produced by each panel is not dependent on the others.
Micro inverters cost more than string inverters for the initial installation, but the increased efficiency will likely pay off in the long run.
Power Optimizers
Power optimizers are similar to micro-inverters, with an inverter attached to the back of each photovoltaic panel. However, they do not convert the DC power to AC.
Instead, they standardize the DC power produced by each panel. The entire array is then connected in a string and sent through a string inverter. Power optimizers are also often referred to as DC optimizers or DC converters.
Hybrid Inverters
Hybrid inverters allow homeowners to utilize off-grid and on-grid power. They work exceptionally well with home battery backup.
A hybrid inverter can still convert the DC power from your solar array into AC power for your home. In addition, hybrid inverters can also convert AC power from the grid into DC power to charge your battery bank.
What Is the Right Size Solar Inverter?
Choosing the right size solar inverter is critical to ensure that your system is efficient and effective. The best size will depend on your solar power system size and your energy needs.
It’s essential to choose an inverter that is large enough to handle the output of your solar panels but not so large that you are wasting money on excess capacity. If you choose an inverter that’s too small, it may not be able to handle the output of your PV panels, leading to reduced performance and efficiency.
On the other hand, if you choose an inverter that’s too large, you’ll be paying for excess capacity that you don’t need.
To determine the correct size solar inverter for your system, it’s a good idea to consult with a solar installation professional or use an online inverter size calculator to help you determine the best size for your specific energy needs.
Applications
Solar inverters have a wide range of applications in both residential and commercial settings.
In homes, solar inverters power everything from small appliances to large HVAC systems and can help homeowners save money on their energy bills — or eliminate them altogether. In addition, they can power office buildings, warehouses, and other extensive facilities in commercial settings, helping businesses reduce their energy costs and carbon footprint.
Solar inverters are also used in industrial environments, such as factories and power plants, to convert electricity from renewable sources. Inverters are an integral part of transitioning to a more sustainable energy future.
Solar Power Inverters: Grid-Tied, Off-Grid,
Solar inverters can work with grid-tied and off-grid systems, as well as hybrid systems. Grid-tied inverters are common and integrate with your home electrical panel. You can use grid power when needed. In some areas, you can sell electricity back to the grid through net metering.
Inverters are an essential component of off-grid solar power systems that offer true energy independence. With off-grid solar, you no longer have to worry about aging infrastructure and power outages caused by extreme weather events. You can eliminate your electricity bills completely by generating enough clean, renewable solar energy to meet your power consumption needs.
Lastly, hybrid inverters combine solar and battery inverters into one component. Hybrid inverters typically will not work without a connection to functioning grid power — meaning that your system is unlikely to work in a power outage.
Choosing the Best Solar Inverter
When choosing a solar inverter, there are several important factors to consider:
- The size of your PV solar panel system
- Your energy consumption needs
- Whether you want to be off-grid or grid-tied
- Your budget
It is also a good idea to research and compare different brands and models to find the one that best meets your needs and budget. Consult with a solar installation professional to get expert advice on the best inverter for your specific situation.
Choose an inverter that is reliable and has a good warranty, as inverters can be expensive to repair or replace if they malfunction or fail.
EcoFlow Power Kits and Power Hub
Trying to choose an inverter and other components can become confusing. You can never be quite sure about compatibility between solar panels, batteries, inverters, and charge controllers. That’s why some companies have put together convenient all-in-one off-grid power solutions.
The EcoFlow Power Kits are an excellent example of a plug-and-play off-grid solar power system. They are perfect for cabins, tiny homes, and RVs.
The Power Hub includes all of the essential converters, outlets, and chargers for an off-grid system, including:
- DC-DC Step-Down Converter
- DC-DC Battery Charger with MPPT
- MPPT Solar Charge Controller
- Solar Inverter Charger
With an all-in-one system, you don’t need to worry about compatibility and whether the inverter is the right type for your solar power system. The Power Kits also work with all models of EcoFlow solar panels (rigid, portable, and flexible) and panels from other manufacturers.
EcoFlow’s Power Hub: What’s in the Box?
DC-DC Step-Down Converter
A DC-DC step-down converter takes the high voltage of PV panels (often 50 volts) and steps it down to the 48V that the EcoFlow Power Kit batteries expect.
DC-DC Battery Charger with MPPT
The DC-DC battery charger with MPPT (multi-power point tracking) allows the battery bank to be charged directly by other DC power sources, such as a car alternator or a service battery.
An MPPT is especially useful in RV and other mobile applications. The technology allows for high-efficiency charging and is superior to similar chargers that use PWM (pulse width modulation) chargers.
MPPT Solar Charge Controller
The integrated MPPT charge controller allows for safe, efficient charging of your battery bank using the power generated by your solar array.
Solar Inverter Charger
The inverter charger allows your system to charge and function using AC power. For example, with an RV installation, you can connect directly to shore power at campgrounds.
Conclusion
A solar inverter is essential to any solar power system. It allows modern AC appliances and devices to utilize the DC power generated by photovoltaic solar panels.
Choosing an inverter can be difficult, as many different models exist. Luckily, manufacturers like EcoFolw have created all-in-one systems that eliminate compatibility issues. EcoFlow’s Smart Home Ecosystem gives you the freedom to customize a solar power solution that’s right for your family’s needs — easily and without compatibility concerns.
Frequently Asked Questions
A solar inverter converts the direct current (DC) electricity your PV solar panels produce into alternating current (AC) electricity — the type of electricity used to run consumer appliances and electronics. Inverters also monitor and optimize your panels’ performance to ensure they safely produce as much electricity as possible.
The best inverter depends on your specific needs, although micro-inverters tend to be more efficient than string inverters. Some factors to consider when choosing an inverter include your PV solar panel system size, your energy consumption needs, whether you want to be off-grid or grid-tied, and your budget.
Grid-tied inverters do not require a battery, as they are connected to the utility grid and send excess electricity to the grid. On the other hand, off-grid inverters require a solar battery to store excess electricity. Some hybrid inverters can work with or without a battery, but most need the grid to be operational to function.
Switching to solar can require a substantial upfront investment — and an inverter is an essential component. Purchasing a solar power system is a long-term investment — it may take years of incremental savings on utility bills to exceed your upfront costs. Government subsidies and financing can help defray initial costs or spread them out over time. When choosing an inverter, keep the long-term in mind — it’s not a good place to cut corners. Cheap inverters may break down frequently, require regular maintenance, and need to be replaced when broken for your balance of system (including solar panels and batteries) to function.
EcoFlow is a portable power and renewable energy solutions company. Since its founding in 2017, EcoFlow has provided peace-of-mind power to customers in over 85 markets through its DELTA and RIVER product lines of portable power stations and eco-friendly accessories.
What does a solar inverter do? How solar inverters work in a PV system
When the sun shines on your solar photovoltaic (PV) system, electrons within the solar cells start to move around, which produces direct current (DC) energy. Circuits within the cells collect that energy for you to use in your home.
This is where your solar inverter comes in. Most homes use alternating current (AC) energy, not DC, so the energy produced by your solar panels isn’t useful on its own. When your solar panels collect sunlight and turn it into energy, it gets sent to the inverter, which takes the DC energy and turns it into AC energy. At that point, your solar electricity can power your appliances and electronics or, if you’re producing more electricity than you need, it can feed back into the grid.
Comparing solar inverter technologies: string inverter vs. string inverters with power optimizers vs. microinverters
All inverters have the same basic task: convert DC solar energy into useful AC energy for your home. However, there are three different solar inverter technologies that you can choose for your solar panel system, and each of them works slightly differently.
String inverters: a standard centralized inverter
Most small-scale solar energy systems use a string inverter, also known as a “central” inverter. In a solar PV system with a string inverter, each panel is wired together into a “string”, and multiple strings (normally up to three) can be connected to your central inverter. When your panels produce energy, it all gets sent to a single inverter, which is usually located on the side of your home, in a garage, or in your basement. The inverter will convert all of the electricity from your solar panels into AC electricity for use on your property.
Pros: String inverters are the lowest-cost inverter option, and are a very durable inverter technology. They are also the easiest to maintain, because they are in an easy-to-access location.
Cons: A drop in the performance of an individual solar panel (i.e., from shading) can impact the output of all of the panels on an individual string. While multiple strings can accommodate multiple roof planes on the same inverter, string inverters may not be right for more complex system designs or roofs with regular shading.
Best for: Properties with “uncomplicated” roofs that get consistent sun throughout the day, and homeowners looking for lower-cost solar PV systems.
Power optimizers: a panel-located option to pair with a string inverter
Power optimizers can be thought of as a compromise between string inverters and microinverters. Like microinverters, power optimizers are located on the roof next to (or integrated with) individual solar panels. However, systems with power optimizers still send energy to a centralized inverter.
Power optimizers don’t convert the DC electricity into AC electricity at the site of the solar panel. Rather, they “condition” the DC electricity by fixing the voltage of the electricity, at which point the electricity is sent down to the string inverter. A system that pairs power optimizers with a string inverter is more efficient than one that uses a string inverter alone in shading scenarios.
Pros: Like microinverters, power optimizers can improve the efficiency of your solar panel system if you have a complicated roof or frequent shading; however, optimizers tend to cost less than microinverters. They optimize the output of each individual panel to mitigate the impact any one shaded panel can have, and also provide the benefit of monitoring the performance of individual panels.
Cons: A system that pairs power optimizers with a string inverter will cost more than a system with a standard string inverter option. As with microinverters, solar PV systems that include power optimizers can be more difficult to maintain.
Best for: Homeowners with a slightly less than ideal roof for solar who are willing to pay more to increase the performance of their solar panel system, but who don’t want to invest in microinverters.
Microinverters: high-performance at a higher cost
If a string inverter can be considered a “central” inverter, microinverters are “distributed” inverters. Solar PV systems with microinverters have a small inverter installed at the site of each individual solar panel. Rather than sending energy from every panel down to a single inverter, microinverter systems convert the DC solar energy to AC energy right on the roof.
Pros: Having microinverters at every solar panel provides performance benefits, especially for systems with a more complicated design or that experience shading. Microinverters optimize the output of every panel at the panel to mitigate the impact of shading, and to allow for panel-level monitoring of your system.
Cons: Microinverters cost significantly more than a string inverter, and can be more difficult to maintain or repair in the event of a problem because they are located on the roof.
Best for: Systems with solar panels that face multiple directions, homeowners who want to maximize solar production in a small space, and properties that have “complicated” roofs with gables, chimneys, or other objects that can cause shade.
Choosing the best inverter option for your home
Now that you understand how solar inverters work, your next step is to decide which type is best for your solar PV system. Not every system-design is right for string inverters, and it’s not always necessary to pay extra for optimizers or microinverters. Ultimately, there’s no universal right or wrong answer, only what’s best for your own situation and needs.
EnergySage has additional resources that can help you make a decision about your solar inverter options:
- Comparing string inverters, microinverters, and power optimizers
- Microinverters vs. power optimizers: which panel-level option is best for you?
- Advantages and disadvantages of microinverters and power optimizers
Additionally, browse all types of solar inverters on the EnergySage Buyer’s Guide, where you can compare inverter metrics across products like efficiency and warranties.
While you can continue to read about the different technologies, the best way to find out which option works for you is to review actual quotes from qualified local installers in your area.
When you register your property on the EnergySage Solar Marketplace, you can review offers that have been customized to your home and evaluate the costs and benefits of different inverter options. Customers who compare quotes on EnergySage can save 20 percent or more on their solar installation simply by evaluating all of their equipment, financing, and installer options.
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What is inverter oversizing?
If you’ve been in the market for solar, you’ve probably come across the concept of oversizing solar inverters. Sometimes called inverter oversizing, this is the concept of installing more solar panels than your inverter is rated for.
While it seems counterintuitive. surely your solar panels and inverters should match in terms of the energy they can process, right? the truth is a little more complicated. There are so many different factors to consider when installing solar panels, and this is one that we reckon is often overlooked.
Read on to discover what oversizing solar inverters actually entails, how it works, and whether it’s the right choice for your solar array installation.
What is an inverter?
An inverter is the heart of your solar installation. It’s a central component that makes it all work for you! The inverter is the part of your system that transforms the DC energy (Direct Current energy) created by your solar panels, into AC (Alternating Current energy) which powers your home or facility.
Without an inverter, there’s no way to utilise the energy that’s produced by your solar panels!There’s a large range of solar inverters in the market, and they can be narrowed down to 3 main types of inverters. The type of inverter that works for your situation may not work for others, and vice versa, so it’s vital that you opt for an inverter that is suited to your specific needs.
What is a solar array?
Simply put, a solar array (or PV array) is the term used to describe a group of solar panels. When you’ve set up a solar system on your property, that’s a solar array! How many solar panels you need. and therefore the size of your array. will depend on your household or facility’s solar needs.
In addition to how you use the energy powered by solar panels, there is also consideration for how much sun you get during the day and how that impacts the average efficiency of solar panels. And that’s where inverter oversizing comes in!
What is Inverter Oversizing?
As we mentioned further up, oversizing solar inverters refers to when you install a solar array (that’s a group of solar panels) with a higher capacity than the rated size of your inverter. Basically, you install more solar panels that your solar inverter capacity is meant to handle.
For example, say you have a 5kW Inverter. This is the most common size in Australia because most energy providers cap the electricity export for homes at 5kW. This means that at any period in time, your solar system can’t export more than 5kW of energy to the Grid. Exporting excess energy to the grid is what happens when you don’t self-consume the energy yourself.
In theory, it would make sense to match a 5kW Inverter with 5kW worth of panels. and many people do this. For such a setup, 5kW of panels will equal 15 panels at 330Watt each. But when you opt for inverter oversizing, you’re setting up more than 5kW worth of panels instead.
On the surface, this does seem a bit odd. Why ‘waste’ all that extra energy if you can’t use it or put it back into the Grid, right?
Well, we’ll tell you why it’s actually a good idea!