Surplus power is usually saved in big batteries to assist nutritional supplement electric power when it’s cloudy. On the other hand, if the off-grid system isn’t producing because of cloudy climate and battery shops are depleted, there's no different source of electrical energy. Tesla also doesn’t give any system customization. https://www.americanarraysolar.com/why-should-you-buy-maintenance-services-from-solar-companies-fresno/