Wide-voltage segmented heating photovoltaic water heater

The invention discloses a wide-voltage segmented heating photovoltaic water heater which comprises a photovoltaic cell panel and a heating water tank and further comprises a photovoltaic heating module composed of at least two electric heating pipes arranged in the heating water tank. The temperature detection device is used for detecting the water temperature in the heating water tank; the voltage detection unit is connected with the photovoltaic cell panel, detects an output voltage value and outputs a voltage signal; the control module is connected with the temperature detection device, the voltage detection unit and the electric heating pipes; the control module sets at least two continuous voltage sections according to an output voltage value of the photovoltaic cell panel, and the control module receives and processes a voltage signal and then sends an instruction to control the electric heating tube to work; and the control module receives a water temperature upper limit instruction sent by the tempera