What are inverters?
An inverter is the basic component of a solar system because they have to pick solar panels’ direct energy and convert it into AC energy or alternating current. This alternating current (AC) is used to run electric devices in a house or industry. More than one type of inverters are available in the market because of which it is sometimes hard to make a choice. In order to find an appropriate solution for your solar panel system, there are a few things that must be considered that will be discussed in detail.
The technology used in inverter systems is growing over time. Micro inverters and string inverters are popular to perform the required job for solar homeowners. The process is undertaken in both cases in different ways as they stack up differently against solar energy but the output is the same.
The string inverter is a standalone box and is placed near the electricity meter and solar panel. In a home solar installation system, only one or two string inverters are used depending upon the size of the system. One string inverter can cater to the need of around 6 to 12 and it is called a series string. Power from the solar panel is aggregated from different solar panels into a system of string. Multiple strings are connected to an inverter and here electricity is generated to run the home appliances.
Advantages of string inverters
String inverter has some inherent advantages like easy troubleshooting and only one inverter can easily convert the DC power taken from solar panel to AC power. The problem in the solar system mainly arises from the issues present in the inverter that affects troubleshooting
Cost of installation
The cost of installing a string inverter with a solar panel is quite less compared to installing a micro inverter as it needs less man-hours.
Fewer chances of wiring errors
As there are fewer connections between the string inverter and its solar panel so string inverter setups are less likely to have wiring issues as compared to microinverter systems.
A string inverter is more user-friendly
The main advantage of a string inverter is its being user-friendly as it has features that allow it to be easily operable. The whole system is solar powered which makes troubleshooting easier. DC electricity can be converted to AC power with the help of only one inverter.
String inverter can be easily maintained cost-effectively because it has minimal wiring so the wiring issues are not faced very often.
Economy of scale
Compared to other inverters that are present in the market string inverter allows economy of scale because of its low price and easy maintenance.
Disadvantages of string inverters
Like any other product string inverters also come with some drawbacks that are discussed as under:
Restricted shade areas make the efficiency of the string inverter less effective. As these inverters usually work in a series so when the efficacy of one inverter is low the entire system starts producing low.
Monitoring of panels
Wreckage or cracks if present in the individual panels may decline the efficacy and therefore it is always necessary to check solar panels for their flow.
The efficiency of string inverter in partially sunny areas
String inverters need all the solar panels connected in a series, so if the performance of one solar panel degrades, the whole system will be equally affected. This can be a big problem if one area of the row of solar panels is present in shade even for some time in a day. Moreover, a string inverter has difficult system expansion, and to get the best performance, it should operate in a way that helps it reach its peak capacity. So to expand the size and efficiency of solar panels one needs to connect them to another string inverter makes the process more cumbersome, short-lived, and expensive.
String inverter systems do not have panel-level visibility because there are no components mounted behind each panel. The process of power generation can be negatively affected by dust particles, cracks, and defects.
A micro inverter will convert AC current into DC current and is known for flexibility in action as it is not prone to a single-point failure. Design flexibility and power optimization of micro-inverter are better as compared to a string inverter. It is known for simplicity in design and simple stock management. If any kind of problems such as snow in lines, debris, or shading occurs, the output of the entire array is not affected and the system keeps generating energy. It is a plug-and-play device that is connected to the system and placed usually on the roof. However, its placement might make its installation and maintenance harder.
Is a micro-inverter better?
A micro inverter will perform the same function as that of a string inverter but is positioned below the solar panel. These invertors will control the power generated by one solar panel and convert energy generated by each panel into line voltage. By using a micro-inverter plenty of electricity can be generated. They also need minimum cost of wiring and have better longevity. The warranty of standard inverters is 8-12 years while that of micro inverters is 25 years. Panel monitoring in the micro inverters is also better because all solar panels can be optimized together and feasibility can be checked.
Micro inverters and their working process
A microinverter is placed with the solar panel and each microinverter will be attached to one solar panel. This is the main difference between microinverter and string inverters because string inverters are centrally placed and one solar system will only have one string inverter. On the other hand, microinverters will be included in the system depending upon the number of solar panels. Micro-inverters are also grounded into module-level power electronics (MLPE) because one micro-inverter works with one solar panel without depending on the other system. It makes them the best choice for areas that are partially shaded or places where the performance of some panels can be compromised because of external factors. One panel with a microinverter can produce energy even when the system is performing at its lowest. If other panels in the solar system are not efficiently working the one in good condition will keep producing. Micro inverters also come in different sizes and their size is also chosen keeping in view the size of the solar panel with which they are being installed. Other factors that determine the size selection of the micro inverter include the direction of the panel, geography, and facing.
Advantages of micro inverters
The automatic shutdown of a micro-inverter with a rapid shutdown procedure allows it to switch off without any extra hardware installation in it. The micro inverter has a software program that is synced with rapid shutdown making the procedure self-sustained.
Rapid shutdown capability
The rapid capacity of shutdown makes micro inverters more feasible and safe as they have a new electrical command that keeps firefighters safe from high electric shocks when they have to go to the rooftop for the response. They can touch powerlines without any danger of shock. Each module of the micro-inverter has the capacity of undergoing rapid shutdown. Furthermore, only a slight difference in the current of the different solar panels makes micro inverters able to generate more electricity from solar power as compared to a string system because in a string the overall current produced is equal to the minimum producing panel in string.
Working in challenging conditions
There are many challenging installation conditions where micro-inverters can be used efficiently as compared to string inverters, especially at places where large chimneys are present or when there are shading issues with trees or any other geographic condition. Here different solar panels produce different amounts of energy depending upon the time of the day. However, when micro inverters are installed, standard electricity power generation is assured and loss of production at different points is stopped.
The lifetime of micro-inverter is longer compared to string inverters because of the latest technology. Previously 8 to 12-year warranties were given but now new technology has allowed improved longevity as the confidence of manufacturers is improving over time.
Panel level monitoring
Monitoring at Panel-level can be done for tracking energy production which makes it easier for the owner to check the production of the whole system by scrutinizing the operation of only one panel. Furthermore, this system can be expanded keeping in view the needs of the user. More solar panels can be added without any hassle because no additional inverters are needed so the overall process becomes less cumbersome.
Summary of the pros: Because of their unique construction and benefits, microinverters are considered a good investment, especially in areas with complex geography in terms of direction, facing, and shading. Optimization of power, compliance and automatic shutdown is independently done at each panel so they are not dependent on the efficacy of the whole system. For instance, when something gets wrong with a micro inverter in the system, the others will keep working with the same efficacy. One underperforming panel will not create an emergency as it happens in centrally working inverter systems. Moreover, more solar panels can be added to the system whenever needed keeping in view the increased demand because the power output of the central inverter is not the main issue here. You do not have to look into the issues such as matching the panels with the system and the size of panels while adding new ones. Because they work for over 25 years so there is always a chance of increasing or reducing power generation with changing demand which is much easier with micro inverters.
A good option of comparison is also available for micro inverters because you have a chance to check which solar panel inverter is working better as there is no need to evaluate the entire system. It will allow servicing of the equipment making it much easier and quicker because only the targeted micro inverter and panel that is failing will be dealt with. The above account reveals that all solar inverters have some pros and cons and none of them is perfect hence you should choose wisely depending upon your requirements. Although, micro inverters’ manufacturers claim that they allow the monitoring of each panel’s output which is considered its benefit but many times consumers are not given the facility of this monitoring. Only the person who has installed the system can check the data and see how much a single panel is producing. So as a customer one can only see the wide information for monitoring and not the specific one. Sometimes broken parts are present but they may not be identified by the user and if only 1 or 2 of the components of the whole system have failed to work it is not easy for the user to know about them. To monitor the system by yourself you need to buy an upgraded monitoring system. While on the other hand, when the string inverter fails or anything occurs with one solar panel the whole system collapse and stops working so it is much easier to notice.
When to use micro inverters
In case of complicated installation procedures, microinverters are preferred because solar panels that are facing different directions will generate to their fullest. The one facing east will not depend on the outcomes of the one in the south. Panels in different directions will produce their maxim ability without affecting themselves with the issues that other panels titled at other angles are experiencing. Although they are more expensive than other inverters and the overall cost of the solar system may increase when micro inverters are included in the system but the upfront cost will soon be overcome with decreased maintenance cost and overall production benefits. However, some people who do not want to invest much in the system might go for a string inverter.
Disadvantages of microinverters
Micro inverters are too pricy as they are constructed with expensive metal, so their per-watt cost is also higher. Replacement and removal of micro-inverter are also difficult as compared to string inverter.
Installation of micro inverters can be cumbersome as they would be installed on the roof leading to space issues. Sometimes their maintenance also becomes difficult as they have to be placed adjacent to the solar panel.
Inability to check the failure point
If the micro-inverter fails to work, it is not easy to identify the failed part. Since the micro inverter is built into the module, it will not be very easy to maintain.
Important points to consider while choosing an inverter
Evaluation of inverters can be tricky because there are many options available in the market. One has to consider different factors while making a choice. These factors will be discussed under
Size of inverter
The size of an inverter vary and different sizes have different ability to handle electricity voltages. For example. Micro inverters that are larger have more capacity and they are more expensive. The size is also finalized keeping in view the energy output of the panel. When a micro inverter is very small and it is linked with a bigger energy output solar panel too much clipping will happen.
The efficiency level of inverters is the main criterion before their choosing. They might have different levels of efficiency depending upon the amount of energy loss as heat when DC to AC electricity is being made. More solar power production will take place if the inverter is of good efficiency and vice versa.
Warranty of the inverter
Different warranties for microinverters and string inverters are available. Mostly for micro inverters 25-year warranty is given nowadays that helps protect the user from degradation and defects while on the other hand, the warranty of string inverters is not very long. It is important to check the level of coverage that is being provided by the manufacturer. Because different manufacturers offering the same micro-inverter may offer different types of coverage.
The cost of micro inverter may not be very high but still, it matters as they make an essential component of the solar system. Usually longer the warranty of a micro-inverter higher will be the price. On the other hand, string inverters are expensive. One has to choose the inverter depending upon the system preferences and warranties being offered.
Micro inverters can be considered as a value-adding component to the solar system because they will not only allow rapid shutdown but at the same time, multiple facing orientation and shading problems will also be solved. They are also less expensive and can prove to be more cost effective in the long run. In addition to this, low rate of failure is also reported in the case of micro inverter because of less need for maintenance.
What inverter you should choose for your home?
The above-discussed elements can help in weighing the advantages and disadvantages of micro inverters and string inverters. Inverters vary in price; micro inverters are expensive while on the other hand, string inverters are very affordable. Micro inverters have a lifespan of 25 years or even more, but string inverters do not have good longevity.
Both string and micro inverters have their very own benefits and drawbacks depending upon their construction and the environment in which they are used. There are a few things that are required to be kept in mind while you are choosing an inverter for your home. The right choice can be made by identifying factors including the efficiency of power generation, longevity, price, monitoring (remote or smart home), troubleshooting steps, performance, system expansion capacity, safety, battery function, reliability, and adaptability to the external situation. Inverters are built to convert the direct current used by appliances into alternating current. The string inverter is a self-contained box that is ideal for solar panel areas without shade on evenly sloping roofs. A micro inverter is mounted behind each solar panel, making it intelligently suitable for use in partially shaded solar places as it maximizes the overall output of each solar panel without being affected by the production of adjacent panels.
The process of Installation of string inverters is easier and simpler compared to micro inverters. Solar micro inverters can be very efficient as compared to string inverters. Micro inverters have a great capability of efficiency and expansion, but string inverters may require separate inverters. Maintenance of string inverters is quite easy which makes their use feasible. The services of Micro inverters can be performed remotely. It is easier to undergo their installation than a string inverter. String inverters may work efficiently at first but decline in output with the passage time, while on the other hand, micro inverters are much more reliable.
The final takeaway
The purpose of a solar inverter is to convert DC (direct current) from solar panels to AC (alternating current) or electricity that is used to run home appliances. Various kinds of inverters are used for this procedure. The inverter is said to be the most complex component of the entire solar system and this is the reason for which manufacturers have always tried to bring devices that are efficient and need less attention. If inverter fails to perform its job the entire solar system collapses. Companies that have decades of experience in the solar inverter business produce both micro inverter and solar inverter to fulfill the needs of different consumers. Choosing the best inverter is not always easy as there some pros and cons to each type of device.