Imagine we’re using a 10kW inverter for this example.
If you have exactly 10kW worth of solar panels hooked up to that 10kW inverter, you might think, “Great! Perfect match, right?” Well, not quite, because your solar panels often don’t produce their full rated power. They’re tested under ideal lab conditions that don’t always match real life. Outside, real-world conditions like the angle of the sun, cloud cover, and temperature all affect the power output, meaning your panels might only hit 100% of their rated capacity for short periods, like on the sunniest, clearest days around noon.
Now, if we leave the system as-is, our 10kW inverter won’t be running at its full capacity most of the time, since the panels are often producing less than their maximum output. This is where the concept of “oversizing” comes in. By adding more than 10kW of panels—let’s say 12kW, for example—we give the system a better chance to keep the inverter working closer to its 100% capacity throughout the day. Even if the panels aren’t producing at full capacity, there’s enough total power coming in to keep the inverter closer to its max output more of the time. This setup allows you to get more energy out of the system over the course of the year.
Of course, on those rare days when the sun is perfect, and all the panels are hitting their full power, the inverter can’t handle more than 10kW, so it “clips” the extra power it can’t use. But this only happens occasionally and for short periods, and it’s a worthwhile trade-off for the boost in efficiency you get the rest of the time. Finally, there’s a science to oversizing—it depends on things like the tilt of your roof, the direction it faces, and the average weather. All of these factors help us figure out the ideal amount of oversizing to keep the inverter running efficiently and make the most of your solar power.
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