Quick Answer
Yes, solar panels can power your home during a blackout, but it's essential to ensure your system is properly configured and sized to meet your energy needs.
Understanding the Grid Connection
To power your home during a blackout, you’ll need a solar panel system with a built-in inverter that can switch to backup power mode when the grid goes down. This is known as a “grid-tie” system with an “auto-transfer switch” (ATS). The ATS automatically transfers power from the grid to your solar panel system and vice versa. A popular option for grid-tie systems is the SMA Sunny Boy inverter, which has an ATS built-in.
Sizing Your Solar Panel System
When sizing your solar panel system, you’ll want to consider your home’s energy needs during a blackout. Start by calculating your average daily energy usage in kilowatt-hours (kWh). For a typical home, this might be around 30 kWh per day. Next, determine the peak sun hours (PSH) for your location, which can range from 4 to 7 hours depending on your latitude and climate. Multiply your daily energy usage by 365 days (or 366 for leap years) and then divide by the number of PSH to determine your system size in watts. For example, if your daily energy usage is 30 kWh and you have 5 PSH, your system size would be around 14,700 watts (or 14.7 kW).
Battery Backup Considerations
While a grid-tie solar panel system with an ATS can provide power during a blackout, it’s essential to consider adding a battery backup system for added reliability. This can be achieved with a standalone battery bank or a hybrid inverter-charger system. When selecting a battery bank, look for deep cycle batteries with a high depth of discharge (DOD) rating, such as the Tesla Powerwall or the LG Chem RESU. The number of batteries needed will depend on your energy storage needs, but a good rule of thumb is to size your system to store at least 10 kWh of energy.
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