In the new global economy, renewable energy is central to solving the energy crisis. As a widely used renewable energy, the technologies of solar energy and energy storage are mature. The energy storage systems of PV system can transfer the generated energy and match the domestic load profile. Nearly 1/3 domestic energy consumption is household water heating system in temperate climates. As the energy storage medium with the most effectiveness, hot water is to be used in this project. Because of the cheap implementation and low maintenance cost, the hot water storage system has also been an important component of a typical household energy budget. This PV conversion is designed for the household hot water heating system which is supplied by PV panels. MPPT method will be employed. The hot water cylinder and solar panels will also be optimized. 75% budget of required domestic hot water can be provided by this PV conversion system.