Quick Answer
A minimum wattage for inverters depends on the solar panel array size and desired output. Typically, inverters are sized to handle the maximum power point of the array, and a common rule of thumb is to choose an inverter with a capacity 20-25% larger than the array.
Inverter Sizing Guidelines
When sizing an inverter, it’s essential to consider the total wattage of the solar panel array. A general rule of thumb is to choose an inverter with a capacity 20-25% larger than the array. For example, if the solar array is 4 kW, the recommended inverter size would be 4.8 to 5 kW.
Factors Influencing Inverter Sizing
In addition to the array size, other factors influence inverter sizing, including the number of DC inputs, battery bank configuration, and desired output. If the array is split into multiple DC inputs, the inverter must be sized to handle the maximum power point of each input. For systems with a battery bank, the inverter may need to be larger to account for the additional power required for charging.
Inverter Efficiency and Over-Size Considerations
Efficiency and over-sizing considerations also play a crucial role in inverter selection. Inverters typically operate at 90-95% efficiency, so a 5 kW inverter may only produce 4.5 kW of AC power at full load. To account for this inefficiency, it’s common to choose an inverter with a capacity 5-10% larger than the array to ensure the system remains within safe operating parameters.
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