Abstract: Remote areas and areas without electricity are usually unable to access the power grid. An off-grid solar-battery system is a good way to decrease local power shortages. To make full use of renewable energy and economically provide power to remote areas and areas without electricity, some additional information regarding influencing variables is needed. We need to identify the expected load rate and life cycle cost, load characteristic, solar resource analysis, actual environment characteristics of photovoltaic modules, energy storage, and power matching characteristics. We used these factors to optimize the design of an offgrid solar-battery system. The results show that the optimal storage of an off-grid solar-battery system can satisfy the local basic power supply economically in a region of Africa.