What are DC appliances, you ask? They are simply normal appliances (refrigerators and freezers) that run on DC power, which, of course, leads to the question: what is DC power?
DC power has some complex technical definitions. For the purposes of solar, we’re just going to say that it is basically low-voltage electricity that can power DC appliances such as a 12 volt refrigerator or a 12 volt freezer. This is important because the energy that solar panels generate comes in the form of DC, as opposed to AC. Many solar setups use expensive inverters to change the DC generated power into AC. This is generally done in grid-tied installations, where the DC power is inverted to AC, because the rest of your house would be wired on AC. However, when you’re doing an off-grid installation there isn’t that same need to invert the power to AC. There are three basic options:
- Invert the power to AC and function as a grid-tied installation would
- Invert the power to AC, but take some of the power load and leave it running on DC in order to reduce the number of panels/batteries you need, and reduce the strain on your system
- Don’t invert and keep the power as DC, and use it to power things that run more efficiently on DC such as DC appliances
Options 2 and 3 are where DC appliances come in. In option 2 the marked advantage to using a DC appliance is the reduction in solar panels and batteries that they require as opposed to a traditional AC variant. Not only do you save on the cost of the panels and batteries, you save on the space they would have taken up as well. In option 3 you save on buying an inverter, which are generally quite costly. You also save again on the batteries and solar panels that would be required to run AC variants of the DC appliances that you use. Option 3 is generally only used in something like a hunting camp or cottage, and not something used daily such as an off-grid home; there options 1 and 2 are much more common.
Want to know more about DC appliances? Feel free to contact us!