The self - sufficient solar power systems heavily rely on off - the grid solar batteries. This is because these batteries store extra power produced during the day for use at night or when it is cloudy. The deep cycle lead - acid or lithium - ion batteries are mostly used. This is because the batteries are able to withstand repeated deep discharges without significant degradation. The system must be carefully tailored in terms of energy consumption, solar panel output, and backup requirements. These off - grid systems reduce energy dependence and reliance on the power grid making them ideal for remote locations or places that need energy security.