Nowadays, the demand for electrical energy is increasing due to the application of electrical equipment such as air conditioning, refrigerators, television, computers etc. Grid-connected photovoltaic is a network that allows for significant penetration of electricity by PV generation into the national utility grid under Net Energy Metering (NEM) incentive. Under NEM incentive, the owner can offset the energy for 10 years to reduce the electricity billing. Unfortunately, after that, the self-consumption (SELCO) program is implemented. Under SELCO program, the energy generated by PV will be consumed by the owner and there is no rebate for excess energy to the grid. This paper represents the techno-economic analysis of different rated power of PV design installed for residential applications. The 1.04kWp, 1.56kWp and 2.08kWp PV are designed to charge 5.544kWh battery and simulated by using PVsyst software. The payback period is calculated under Net Energy Metering (NEM) 3.0 incentive. As a result, 1.56kWp is the optimize sizing for grid-connected PV-battery with electricity billing saving at RM730.20 per year under one-on-one program and RM660.61 under SELCO program. Thus, return on investment (ROI) of this system design is 16.5 years.