Micro inverters

A module inverter, also known as a micro inverter, is a small electronic device that is attached directly to a solar module. In contrast to a central inverter, which combines and converts the direct current (DC) from several modules, the module inverter works modularly.

How it works:

1. Direct current generation: Solar modules generate direct current (DC) when exposed to sunlight.
2. Conversion to alternating current: The module inverter converts the direct current generated by the solar module into household alternating current (AC).
3. Feed-in or self-consumption: The alternating current generated can either be fed directly into the household or stored in batteries for later use.

Advantages over central inverters:

• Higher Efficiency: Since the conversion to alternating current takes place directly at the module, less energy is lost through cables and string optimizers.
• Greater safety: If a module fails, only the output of this module is lost, not that of the entire system.
• More flexibility: Module inverters are better suited to shaded roofs or systems with different orientations.
• Easier service: Troubleshooting and maintenance are easier because each module is controlled individually.

Disadvantages:

• Higher acquisition costs: Module inverters are generally more expensive than central inverters.
• More components: Installation requires more components and Wiring.
• Potentially higher maintenance costs: The higher number of devices can increase maintenance costs.

Conclusion:

Modular inverters offer several advantages over central inverters thanks to their modular approach. They are particularly suitable for complex roof shapes, shady areas and systems with different module types. The higher acquisition costs are partially offset by the higher efficiency and greater safety.

Whether a modular inverter is the right choice for you depends on your individual requirements and the configuration of your solar system. It is best to seek advice from a specialist.

Module inverters, also known as micro inverters, offer several advantages over central inverters, which can particularly affect the performance, reliability and flexibility of your solar system:

Higher yield:

• Minimal losses: Since each micro inverter optimizes one module individually, there is no loss of performance due to weaker modules in the string or partial shading.
• Improved efficiency: micro inverters often operate at a higher efficiency, especially in low light conditions, resulting in a higher energy yield leads.

Greater reliability:

• Resilience: The failure of a single module or micro inverter does not affect the performance of the rest of the system.
• Maintainability: Easy troubleshooting and replacement of individual components reduce downtime and simplify maintenance.

Increased flexibility:

• Scalability: micro inverters are ideal for gradually expanding your solar system, as new modules can be easily added.
• Versatile design: They offer more freedom in arranging the modules, as they can be aligned and installed independently of one another.
• Shade tolerance: Partial shading of individual modules has little impact on the overall yield thanks to the optimization by micro inverters.

Additional advantages:

• Lower cable losses: The shorter cable distances between modules and inverters reduce line losses.
• Potentially higher safety: micro inverters work with a lower DC voltage, which reduces the risk of electric shock.

Disadvantages of micro inverters:

• Higher acquisition costs: micro inverters are generally more expensive than central inverters.
• Greater space requirement: Due to the large number of individual components, they require more Installation area.
• More complex installation: The installation requires more cabling and distribution technology.

Conclusion:

The decision between module and central inverters depends on your individual needs and the conditions of your solar system. micro inverters offer advantages in terms of performance, reliability and flexibility, but require higher investment costs and greater installation effort. Central inverters, on the other hand, score points with lower acquisition costs and easier installation, but can experience performance losses if there is shading or individual modules fail.

It is therefore advisable to carefully weigh up the advantages and disadvantages of both systems and, if in doubt, consult a photovoltaic expert to find the optimal solution for your solar system.

When choosing the right micro inverter for your photovoltaic system (PV system), various factors play an important role in ensuring optimal performance and efficiency. Below are some important points to consider when making your selection:

1. Power and dimensioning:

• The nominal power of the inverter must at least correspond to the total power of the connected solar modules. It is better to plan some buffer to enable future expansion of the system.
• Note the overcrowding rules that apply to PV systems in Germany. These allow the modules to be oversized by up to 10% to compensate for yield losses due to shading or low solar radiation.

2. Technology and efficiency:

• Modern micro inverters work with different technologies, such as string or central inverters. Each technology has its own advantages and disadvantages that you should consider when making your selection.
• The efficiency of the inverter indicates how efficiently it converts the direct current from the solar modules into grid-compliant alternating current. A high efficiency of over 95% is recommended.

3. Special functions and features:

• MPP tracker: High-quality inverters have several MPP trackers that determine the optimal operating point of each solar module and thus maximize the yield.
• Emergency power function: Some inverters can serve as an emergency power supply in the event of a power failure and thus cover the household's electricity needs.
• Protection functions: Pay attention to comprehensive protection functions against overvoltage, short circuit and other sources of error to ensure the safety and longevity of the system.

4. Quality and guarantee:

• Choose an inverter from a reputable manufacturer with a good reputation and experience in the field of photovoltaics.
• Make sure you get a long guarantee period of at least 5 years, ideally 10 years or more.

5. Installation and service:

• Make sure that the inverter you choose is installed and maintained by a certified specialist installer.
• Find out about the availability of services and spare parts in your area.

Additional tips:

• Online comparison portals and specialist magazines offer helpful information and test reports on various micro inverters.
• Get advice from an independent solar installer who can help you choose the right inverter for your individual needs.

Choosing the right micro inverter is an important decision for the success of your photovoltaic system. By considering the points mentioned above, you can make an informed decision and ensure that your system produces electricity efficiently and reliably.

The prices for module inverters (also called micro inverters) vary depending on the manufacturer, performance and additional functions. On average they are between €120 and €180 per unit.

Please note:

• The cost per kWp decreases as the performance of the micro inverter increases.
• In addition, there are installation costs, which can be between €100 and €300 per kWp depending on the effort involved.
• Unlike string inverters, micro inverters do not require installation on the roof as they are mounted directly on the module.

Advantages of micro inverters:

• Higher yield: Each micro inverter optimizes the performance of the respective module, which can lead to a higher overall yield.
• Greater shade tolerance: If individual modules are affected by dirt or shade, this has no effect on the performance of the other modules.
• Failure safety: If a micro inverter fails, this has no effect on the other modules.
• Flexibility: The system can be expanded with additional modules at any time.

Disadvantages of micro inverters:

• Higher purchase costs: Compared to string inverters, micro inverters are significantly more expensive to purchase.
• Higher installation effort: Since each micro inverter has to be mounted individually, the installation effort is higher.
• More components: Due to the large number of There are more components in micro inverters that can fail.

Conclusion:

Whether micro inverters are the right choice for you depends on your individual needs and the configuration of your solar system. It is best to seek advice from a specialist.

Whether you can install a micro inverter yourself depends on your technical skills and the scope of the installation.

Basically permitted:

• In Germany, you are permitted to install the inverter and do the wiring on the direct current side (DC), i.e. from the module to the inverter, yourself.Registration with the network operator is also generally possible without an electrician.

Required specialist knowledge:

• Connection to the house network and the public power grid (AC side) may only be carried out by a registered electrical engineer.
  • This also applies to the commissioning of the system.
  • Expert knowledge in the field of electrical engineering and photovoltaics is recommended for the entire installation in order to avoid errors and safety risks.

Recommendation:

• For a complete self-installation with registration with the network operator, you should definitely seek advice from an electrical engineer.
• They can explain the necessary steps to you and take over parts of the installation if necessary.
• This way you can reduce costs, while ensuring the safety and proper operation of your system.

Additional information:

• Installation requirements: Observe the regulations of the network operator and the guidelines for low-voltage systems (DIN VDE 0100-551).
• Safety instructions: Always work without power and observe the safety instructions of the manufacturers of modules and inverters.
• Documentation: Document all Installation steps and keep the documents in a safe place.

Conclusion:

With technical know-how and with the involvement of an electrical engineer for the electrical connections and commissioning, the self-installation of a micro inverter is possible.However, safety and professional installation should always have the highest priority.

Regular maintenance of your micro inverter is important to ensure the performance and service life of your photovoltaic system. Below you will find out how you can maintain your inverter yourself:

Before maintenance:

• Observe safety: Make sure that the photovoltaic system is de-energized. To do this, switch off the main circuit and use a voltage tester to check that there is no longer any voltage.
• Obtain information: Obtain the operating instructions for your inverter. This contains important information on maintenance intervals and the steps required.
• Tools and materials: Obtain the necessary tools and materials, e.g. E.g. an Allen key, a Torx screwdriver, a dust cloth and rubbing alcohol.

Maintenance Steps:

1. Visual Inspection: Check the inverter for visible damage such as dents, cracks or corrosion.
2. Ventilation: Make sure the inverter's ventilation holes are clear and not blocked by dust or dirt.
3. Connections: Check all connections for tightness and corrosion. Tighten the screws if necessary.
4. Grounding: Check the grounding of the inverter.
5. Software update: Check if a software update is available for your inverter. Carry out the update if necessary.
6. Data check: Check the recorded data of the inverter for any abnormalities.
7. Cleaning: Clean the inverter with a dust cloth and cleaning alcohol.

After maintenance:

• Switch on the voltage: Switch the main circuit back on.
• Function test: Check the function of the inverter.
• Documentation: Document the maintenance work carried out.

Recommendations:

• Recommended Maintenance intervals: The recommended maintenance intervals for micro inverters vary depending on the manufacturer and model. As a rule, however, the inverter should be serviced at least once a year.
• Professional maintenance: For comprehensive maintenance of your inverter, you should call in a specialist. They can also diagnose and correct any errors.

Additional information:

• Warranty: Observe the warranty conditions of your inverter. Carrying out maintenance yourself can affect the warranty claim.
• Dangers: There is a risk of electric shock when servicing an inverter. Therefore, only carry out maintenance if you have the necessary knowledge and skills.

In summary, maintaining a micro inverter is not difficult, but there are a few important steps to follow. With regular maintenance, you can ensure the performance and service life of your photovoltaic system.

The life expectancy of a micro inverter is on average 20 to 25 years.

It is important to note, however, that this is only a guideline and the actual lifespan depends on various factors, such as:

• Quality of the inverter: High-quality inverters from reputable manufacturers tend to last longer than cheaper models.
• Environmental conditions: Inverters exposed to extreme temperatures, high humidity or dust may have a shorter lifespan.
• Stress: Inverters that are constantly operated at their power limit will wear out faster than inverters that operate at a lower power
• Maintenance: Regular maintenance can extend the life of an inverter.

There are a few signs that an inverter has reached the end of its lifespan:

• Performance degradation: The inverter no longer produces full power.
• Common error messages: The inverter frequently displays error messages.
• Overheating: The inverter overheats more frequently.
• Noises: The inverter makes unusual noises.

If you notice any of these signs, you should have your inverter checked by a professional let.

It is also important to note that technological development in the field of photovoltaics is constantly advancing. It is therefore possible that newer and more efficient inverters will come onto the market in the future, which will have a longer lifespan.

In summary, the lifespan of a micro inverter depends on various factors. However, with high quality, good environmental conditions, moderate load and regular maintenance, an inverter can be expected to last for 20 to 25 years.

Before carrying out any work on your photovoltaic system, you should observe the following safety measures:

• Disconnect the system from the power supply: Make sure that the inverter is disconnected from the power grid and the DC side of the PV system. To do this, use the switches and fuses provided.
• Check that there is no voltage: Use a voltage meter to ensure that there is no voltage on the cables.
• Observe the instructions in the operating manual: The operating manual for your inverter contains important information on troubleshooting and safety instructions for maintenance work.

Possible causes and first steps:

• Fault display on the inverter: Check the LEDs or displays on the inverter or in the associated app for error codes or warning messages. These can give you an initial indication of the cause of the problem.
• Blown fuses: Check the fuses in the inverter and in the fuse box in your house. Defective fuses must be replaced.
• Connection problems: Check all cable connections on the inverter and solar modules for tightness and damage.
• Environmental conditions: Make sure the inverter is adequately ventilated and not exposed to extreme temperatures.

Next steps:

• Resetting the inverter: In some cases, resetting the inverter can solve the problem. Follow the instructions in the user manual.
• Expert help: If you cannot find the cause of the problem yourself or are unsure how to proceed, you should call in a specialist. A certified solar installer or electrician can check the system and fix the problem.

Recommendations:

• Regular maintenance: Have your photovoltaic system serviced regularly by a specialist. This way, errors can be identified and fixed early, before the micro inverter fails.
• Warranty: Check whether your micro inverter is still under warranty. In this case, you can contact the manufacturer or dealer to have the device repaired or replaced.
• Insurance: A photovoltaic insurance policy can reimburse you for the cost of repairing or replacing the device if the micro inverter is defective.

In summary, a failed micro inverter is a problem, but in most cases it can be fixed. Follow the safety instructions, proceed systematically and do not be afraid to call in a specialist if necessary.