You can’t install a solar array without an inverter. Regardless of the specific type of solar cells — monocrystalline, polycrystalline, etc. — all solar panels generate direct current (DC) electricity. Residential and commercial buildings, of course, primarily use alternating current (AC) electricity. With a solar inverter, though, you can install a solar array to power your home or building.
Also known simply as an inverter, a solar inverter is a device that converts DC electricity into AC electricity. They are used in solar arrays. Electricity will flow from the solar panels to the inverter, at which point it will be converted from DC to AC. While all solar inverters can perform the necessary DC-to-AC conversion, they are available in different sizes.
Solar Inverter Sizes Explained
The “size” of a solar inverter doesn’t refer to its physical size or dimensions. Rather, solar inverters are sized based on watts.
Both solar panels and solar inverters are rated in watts. This rating reflects their respective size as well. You can find the size of a solar inverter by checking its rating.
Undersized Solar Inverters
When choosing a solar inverter, aim for a size that’s slightly bigger than that of your solar array. Many solar experts recommend a ratio of about 1.25. In other words, solar inverters should be about one-quarter larger — in terms of watts — than the solar arrays with which they are used.
Choosing an undersized solar inverter will limit the amount of usable electricity your solar array can generate. The solar panels in your array will generate AC electricity. AC electricity, of course, isn’t usable; it must be converted into DC electricity so that it can power the appliances and electrical systems in your home or building.
If your solar inverter is smaller than your solar array, you’ll generate less usable electricity from it. The solar inverter can only generate electricity up to the watts for which it’s rated, regardless of whether the solar array is larger and rated for more watts.
Oversized Solar Inverters
Oversized solar inverters can cause problems as well. It won’t necessarily limit the amount of usable electricity your solar array generates. But an oversized solar inverter can make your solar array less efficient.
You can still choose a solar inverter that’s larger than your solar array. It’s not uncommon, in fact, for solar inverters to be one-quarter larger than their solar arrays. However, you should avoid choosing a solar inverter that’s excessively large.