PV Off-grid power system is consisted of PV module, PV Off-grid inverter with controller and household load. Using PV module to transfer Solar energy directly to electricity, it is stored in battery. When being connected to load, Off-grid inverter will transfer battery energy to single phase AC electricity to run household load, provide reliable and integrative power solution for non-electricity and power shortage area. Meanwhile,  in the area with power grid or diesel engine, if the power grid is not stable, or if the use-cost of diesel engine must be reduced, the system will manage energy automatically. It will ensure normal usage of household load and reduce the cost of usage.