How to choose the power of an inverter
Why size my photovoltaic inverter?
Sizing your solar inverter is crucial to maximizing the annual energy production of your solar installation. The goal is to achieve an optimal balance between the power produced by the solar panels and the conversion efficiency of the inverter. If you install an inverter with a power equal to or greater than that of the solar panels, the inverter will often operate at a low load rate, which reduces its conversion efficiency.
In fact, inverters are most efficient when they operate close to their maximum capacity. Thus, to optimize annual energy production, it is recommended to choose an inverter whose power is approximately 80% of the nominal power of the solar panels.
This approach minimizes the loss of production due to undersizing while maximizing the conversion efficiency of the inverter. For example, an inverter with a power equivalent to 80% of that of the solar panels can offer a net gain of approximately 4.7% in overall efficiency over a year, offsetting the losses due to the limitation of the solar power produced. This demonstrates the importance of properly sizing your inverter to optimize the performance of your photovoltaic installation.
What power for my photovoltaic inverter?
When it comes to photovoltaic inverters, the rule of "who can do more can do less" does not apply. Optimal sizing is not achieved by choosing a power equal to that of the solar installation.
On the contrary, it is recommended to choose an inverter whose power is about 80% of the nominal power of the solar panels. For example, for a solar field of 3.75 kWp, a 3 kW inverter is ideal.
Similarly, for a 390 Wp panel, a 295 W IQ7+ microinverter is recommended. This optimal ratio allows the inverter to operate at its maximum output more often, which improves the overall performance of the installation.
For microinverter technologies, this optimality ratio is even lower, around 75%, as attested by the Enphase technical document. By following these recommendations, you ensure better efficiency and optimized energy production for your photovoltaic installation.
Types of inverters according to power
Photovoltaic inverters vary in the power they are capable of handling, being classified into several types suitable for different sizes and configurations of solar installations.
For small residential installations, microinverters are commonly used. They are installed on each individual solar panel, allowing for granular optimization and typical power output up to 350W per unit, such as the 295W IQ7+ model. Enphase's IQ8 series was developed to meet the needs of large-power panels.
For medium-sized installations, such as homes and small businesses, string inverters are common. These inverters, like the Sunny Boy 2.5, can handle power outputs of a few kilowatts, typically between 1 kW and 5 kW.
Finally, hybrid inverters can manage both solar energy conversion and battery storage system integration, providing additional flexibility for varying power levels depending on the specific needs of the installation. These different types of inverters allow for optimizing performance and energy management based on the size and characteristics of each solar installation.
Is it mandatory to connect a battery with a hybrid inverter?
Can I buy a battery later?
No, you don’t have to connect a battery with a hybrid inverter right from the start. A hybrid inverter can operate without a battery, managing the energy produced by the solar panels and the energy supplied by the electricity grid. This allows the inverter to supply the solar electricity directly to your appliances and send the excess to the grid.
You can definitely buy and install a battery later. The advantage of a hybrid inverter is its flexibility: it is designed to easily integrate an energy storage system when it is added to your installation. This allows you to spread the investment over time and benefit from technological advances and price reductions in the battery sector. This means you can start by optimizing your solar consumption and add a battery later to store the excess energy, increasing your energy independence and reducing your dependence on the electricity grid even more.
What is the backup function on an inverter?
The online backup function of an inverter is essential to maintain PV production even during a power outage. This function allows devices connected to the backup circuit to operate without interruption, as the battery automatically takes over when the power grid is interrupted. This ensures uninterrupted and stable power supply for critical equipment. In a Huawei environment, it is necessary to use optimizers in addition to the backup box to ensure a seamless transition. Without these optimizers, it can take up to a minute for the battery to take over, which can result in a short service interruption. This configuration ensures that your PV system continues to produce energy and power your devices even during power outages, providing a reliable and efficient solution for energy management.
Protection against voltage variations
Protection against voltage fluctuations and lightning is crucial for the safety and longevity of your electrical devices and network. Voltage fluctuations, such as surges and brownouts, can damage sensitive equipment, shorten its lifespan, and cause malfunctions. Installing protective devices such as UPSs with voltage regulators can stabilize the power supply, ensuring a consistent and safe voltage for your devices. Huawei includes AI-powered AFCI as standard to proactively mitigate fire risks
Wattage Consumption Rating
Measuring wattage consumption is essential for effective management of any electrical network. By determining the consumption of your devices and equipment, you can optimize your energy costs and ensure the safe and reliable operation of your network. This involves measuring or estimating the energy needs of each electrical device, whether it is office equipment, household appliances or industrial systems. An accurate assessment also allows you to properly size backup solutions, such as inverters and generators, ensuring that your electrical network can support the loads under all circumstances.
Oscaro Power Configurator
For an accurate assessment of your inverter and battery needs, use our configurator , an automatic sizing tool developed by our experts.
