Solar & battery
Solar Inverter Size Calculator
Inverter size for an array, including the DC to AC ratio installers deliberately run above one.
Result
Oversizing the array relative to the inverter is deliberate. Panels rarely reach their rating, so a ratio of 1.15 to 1.3 keeps the inverter working near its efficient range for more of the day and loses only a fraction of a percent of annual energy to clipping. For an off-grid or hybrid inverter, the starting surge of motors usually sets the size rather than the array.
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About this calculator
Is clipping a problem?
Almost never at normal ratios. It occurs for a few hours on the brightest days and typically costs well under 1% of annual production, which is far less than the inverter saving.
What sets the size on an off-grid system?
The loads, not the array. A well pump or compressor starting can draw several times its running wattage for a second, and an inverter that cannot supply that surge will simply trip.
The formula
inverter kW = array kW DC / DC-to-AC ratio
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