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The functions and differences of solar controllers
The full name of solar controller is solar charge and discharge controller. It is an automatic control device used in solar power generation systems to control multiple solar cell arrays to charge batteries and batteries to supply power to solar inverter loads. It stipulates and controls the charging and discharging conditions of the battery, and controls the power output of the solar cell components and the battery to the load according to the power demand of the load. It is the core control part of the entire photovoltaic power supply system.
The role of solar controller
The basic function of a solar controller is to control the battery voltage and open the circuit. When the battery voltage rises to a certain level, it stops battery charging.
Controllers are used in most photovoltaic systems to protect batteries from overcharging or over-discharging. Overcharging may vaporize the electrolyte in the battery, causing failure, while over-discharging the battery may cause premature battery failure. Overcharging and over-discharging may damage the load, so the controller is one of the core components of the photovoltaic power generation system and is also the balancer. The main part of the system BOS (Balance Of System).
Simply put, the functions of solar controllers can be divided into:
- Power adjustment function.
- Communication function: simple instruction function and protocol communication function, such as RS485 Ethernet, wireless and other forms of background management.
- Complete protection functions: electrical protection, reverse connection protection, short circuit protection, overcurrent protection, overcharge protection, overdischarge protection, etc.
The difference between solar controllers
Popular solar controllers on the market mainly include ordinary solar controllers, PWM solar controllers and MPPT solar controllers.
The working principle of an ordinary solar controller is to directly connect the output of the solar panel to the battery port, and disconnect it when the battery is sufficient. Due to the internal resistance of the battery, it is difficult to fully charge the battery, and the solar panel is not fully utilized. The charging conversion efficiency is only 70-76%.
PWM refers to pulse width modulation. PWM solar controller uses the digital output of a microprocessor to control analog circuits. It is a method of digitally encoding analog signals. Controlling analog circuits digitally can greatly reduce the cost and power consumption of the system, and the charging conversion efficiency is 75-80%.
MPPT (Maximum Power Point Tracking) refers to maximum power tracking. MPPT solar controller can detect the power generation voltage of solar panels in real time and track the highest voltage and current value (VI), so that the system can charge the battery with maximum power output. MPPT tracking efficiency is 99%, and the power generation efficiency of the entire system can be as high as 97%.