4kw solar power system for home use, cheaper ,high efficiency,portable,full set of solar power system Off-Grid Solar Power Home System(4.0KWp ... ,Shandong Province, China for 1 sets$10,082.00Maximum Power (Pmax)250W(4pcs) Maximum Power Voltage (Vpm)31.17V Maximum Power Current (Ipm)8 ... System Voltage4000V Cell Efficiency17.40% Module Efficiency15.30% 4KW solar power system for home