Quick Answer
Yes, you can downsize your solar array after installing a battery, but the ideal size depends on your energy usage, battery capacity, and solar irradiance in your area.
Assessing Your Energy Needs
When downsizing your solar array, it’s essential to assess your energy needs, especially critical loads that require a stable power supply during outages. For example, if you have a 10 kW Powerwall battery, you can reduce your solar array size by 2-3 kW, considering your energy usage pattern and battery capacity. A typical rule of thumb is to maintain 80% depth of discharge (DOD) on your battery during extended outages.
Considerations for Enphase EG4 and Critical Loads
If you’re using an Enphase EG4 system with whole home battery backup, you can downsize your solar array by analyzing your energy usage data. Identify critical loads that require backup power, such as refrigerators, medical equipment, and sump pumps. Based on your energy usage, you can adjust your solar array size to ensure adequate backup power during outages. For instance, if you have 5 kW of critical loads, you may want to maintain a 5 kW solar array to recharge your battery during the day.
Automatic Transfer Switch (ATS) Considerations
When downsizing your solar array, consider the Automatic Transfer Switch (ATS) capabilities. The ATS should be configured to seamlessly transfer power between grid, solar, and battery sources. Ensure the ATS can handle the reduced solar array size and still provide stable power to critical loads. In this scenario, you may need to adjust the ATS settings to compensate for the reduced solar array size and battery capacity. Consult your system documentation and contact the manufacturer for guidance on adjusting ATS settings.
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