1. Low-power photovoltaic controller
(1) At present, most low-power photovoltaic controllers use low-loss, long-life MOSFET and other electronic switching devices as the main switching devices of the controller.
(2) Use pulse width modulation (PWM) control technology to quickly charge and float the battery, so that the solar power generation energy can be fully utilized.
(3) It has single-channel, dual-channel load output and multiple working modes. Its main working modes are: normal on/off working mode (that is, working mode not controlled by light and time), light control on/light control off working mode, light control on/time control off working mode.
The length of time for the time control of the dual load controller to close can be set separately.
(4) It has a variety of protection functions, including battery and battery components reverse connection, battery open circuit, battery overcharge and overdischarge, load overvoltage, anti-reverse charge at night, controller temperature is too high and other protection functions.
(5) Use the LED indicator to display the working status, charging status, battery power, etc., and display the system working status and the remaining battery power through the change of the number or color of the LED indicator.
(6) With temperature compensation function. Its function is to set a more reasonable charging voltage for the battery under different working environment temperatures to prevent overcharging and undercharging from causing premature decline in battery charge and discharge capacity or even premature scrapping. Generally, when the battery temperature is lower than 25°C, the battery should require a higher charging voltage in order to complete the charging process. Conversely, when the battery temperature is higher than 25°C, the battery requires a lower charging voltage. Usually the temperature coefficient of a lead-acid battery cell is -4mV/℃.
2. Medium power photovoltaic controller
Generally, a controller with a rated load current greater than 15A is called a mid-power controller. Its main performance characteristics are as follows.
(1) The LCD screen is used to display various important information such as working status and charging and discharging, such as battery voltage, charging current and discharging current, working mode, system parameters, system status, etc.
(2) With automatic/manual/night functions, the control mode of the load can be programmed to be automatic or manual. In manual mode, the load can be turned on or off manually. When the night function is selected, the controller will turn off the load during the day; when the night is detected, it will automatically turn on the load after a period of delay, and the load will be automatically turned off when the time is up. The delay time and timing time are programmable.
(3) It has multiple protection functions such as battery overcharge, overdischarge, output overload, overvoltage, and high temperature.
(4) It has the function of temperature compensation of float voltage.
(5) With fast charging function. When the battery voltage is lower than a certain value, the fast charging function is automatically turned on, and the controller will increase the charging voltage of the battery; when the battery voltage reaches the ideal value, the fast charge countdown program is started, and the fast charge state is exited after the time expires to achieve the purpose of making full use of solar energy.
(6) The medium-power photovoltaic controller also has a normal charging and discharging work mode (that is, a work mode that is not controlled by light and time), a light control on/light control off work mode, and a light control on/time control off work mode.
3. High-power photovoltaic controller
The high-power photovoltaic controller adopts a microcomputer chip control system and has the following performance characteristics.
(1) It adopts LCD liquid crystal dot matrix module display, which can be set and adjusted arbitrarily through programming according to different occasions. The charging and discharging parameters and temperature compensation coefficient are arbitrarily set. It has a Chinese operation menu, which is convenient for users to adjust.
(2) It can be adapted to the special requirements of different occasions, and can avoid the oscillation caused by the simultaneous opening and closing of various charging switches.
(3) The charging status of each photovoltaic and the on-off status of the load can be displayed through the LED indicator.
(4) There are 1 to 18 solar battery input control circuits, the control circuit is completely isolated from the main circuit, and it has a very high anti-interference ability.
(5) It has the power accumulation function, which can display the battery voltage, load current, charging current, photovoltaic current, battery temperature, accumulated photovoltaic ampere-hours and watt-hours, accumulated load power watt-hours and other parameters in real time.
(6) With historical data statistics display function, such as overcharge times, overdischarge times, overload times, short circuit times, etc.
(7) The user can set the on-off state of the load when the battery is overcharged and over-discharged.
(8) Each charging voltage detection has a “hysteresis” control function, which can prevent the switching device from entering the oscillation state.
(9) It has a series of alarm and protection functions such as battery overcharge, overdischarge, output overload, short circuit, surge, solar battery connection or short circuit, battery connection, night anti-reverse charging, etc.
(10) Passive dry nodes required for generator or backup power starting circuit can be provided according to system requirements.
(11) Equipped with RS232/485 interface, which is convenient for remote communication and remote control; the PC monitoring software can measure real-time data, display alarm information, modify control parameters, and read historical data such as the maximum voltage of the battery per day, the minimum voltage of the battery, the cumulative daily photovoltaic power generation and the cumulative daily load power consumption for 30 days.
(12) The parameter setting has a password protection function and the user can modify the password.
(13) It has protection and alarm functions such as overvoltage, undervoltage, overload, and short circuit. Alarm or control contacts with multiple passive outputs, including battery overcharge, battery overdischarge, start-up control of other power generation equipment, load disconnection, controller failure, flooding alarm, etc.
(14) The working mode can be divided into ordinary charging and discharging working mode (step-by-step current limiting mode) and one-point charging and discharging mode (PWM working mode). The one-point charging and discharging mode is divided into 4 charging stages, the control is more precise, the battery is better protected from being overcharged, and the solar energy is fully utilized.
(15) It has the function of real-time clock without power failure, which can display and set the clock.
(16) With lightning protection function and temperature compensation function.