GB/T 19064-2003 has specific requirements for the main technical indicators of the controller: the loss of the controller should be small, and the maximum power consumption of the controller should not exceed 1% of its rated charging current; it is stipulated that the voltage drop during charging or discharging of the controller should not exceed 5% of the rated voltage of the system. The main technical parameters of the photovoltaic controller are as follows:
(1) Rated voltage. The system voltage is also called the rated working voltage, which refers to the DC working voltage of the photovoltaic system. The voltage is generally 12V, 24V, 48V, 110V, 220V, etc.
(2) Maximum charging current. The maximum charging current refers to the maximum current output by the solar cell module or simulation. According to the power, it can be divided into 5A, 6A, 8A, 10A, 12A, 15A, 20A, 30A, 40A… 250A, 300 A and many other specifications. Some manufacturers use the maximum power to express it, which indirectly indicates the technical parameter of the maximum charging current.
(3) Battery overcharge protection voltage (HVD). The battery overcharge protection voltage is also called the full disconnection voltage or the overvoltage shutdown voltage. It is generally set according to the needs and battery types, 14.1-14.5V (12V system), 28.2~29V (24V system) and 56.4~58V (48V system). Typical values are 14.4V, 28.8V, and 57.6V.
(4) The battery charging protection restores the charging voltage (HVR). The battery charging protection recovery charging voltage is generally set to 13.1~13.4V (12V system), 26.2~26.8V (24V system) and 52.4~53.6V (48V system). Typical values are 13.2V, 26.4V and 52.8V respectively.
(5) Battery over-discharge protection voltage (LVD). The battery over-discharge protection voltage is also called under-voltage shutdown voltage. It is generally set according to needs and battery types, 10.8~11.4V (12V system), 21.6~22.8 V (24V system) and 43.2~45.6V (48V system). Typical values are 11.1V, 22.2V, and 44.4V respectively.
(6) Battery over-discharge recovery discharge voltage (LVR). The battery over-discharge recovery discharge voltage is generally set to 12.1~12.6V (12V system), 24.2~25.2V (24V system) and 48.4~50.4V (48V system). Typical values are 12.4V, 24.8V and 49.6V.
(7) Floating voltage for battery charging. The battery charging float voltage is generally 13.7V (12V system), 27.4 V (24V system) and 54.8V (48V system).
(8) Loss of the circuit itself. The loss of the controller circuit itself is also called no-load loss or maximum self-consumption current. In order to reduce the loss of the controller and improve the efficiency of the photovoltaic power supply, the loss of the circuit itself of the controller should be as low as possible. The maximum self-loss of the controller must not exceed 1% of its rated charging current. Depending on the circuit, the self-loss is generally 5~20 mA.
(9) The number of input channels of the solar cell array. Low-power photovoltaic controllers are generally single-channel input, while high-power photovoltaic controllers are multi-channel input by solar battery packs, generally 6 channels can be input, and up to 12 channels and 18 channels can be connected.
(10) Working environment temperature. The use or working environment temperature of the controller is generally -20℃~ +50℃.
(11) Temperature compensation. The controller generally has a temperature compensation function to adapt to different working environment temperatures. The temperature compensation coefficient of the controller should meet the technical requirements of the battery, and its temperature compensation value is generally -2 ~ -4 mV/℃.
(12) Other protection functions. Controllers generally also have anti-reverse charging protection, reverse polarity protection, short-circuit protection, lightning protection, impulse voltage and impulse current protection, etc. (More controller functions)