If you plan to install an off-grid solar system with a battery pack, you need a solar charge controller. It is a device placed between the solar panel and the battery pack to control the electricity generated by the solar panel entering the battery. The main function is to ensure that the battery is properly charged and prevent overcharging.
Currently, two types of charge controllers are generally used in PV power systems: 1. Pulse width modulation (PWM) controllers. 2. Maximum power point tracking (MPPT) controllers.
PWM solar controller:
PWM, or pulse width modulation, is a method used to adjust electric charge. Its function is to pull down the voltage of the solar cell array to be close to the voltage of the battery to ensure that the battery is properly charged. It uses an electronic switch (MOSFET) to connect and disconnect the solar panel from the battery. By switching the MOSFET at a high frequency with various pulse widths, a constant voltage can be maintained. The PWM controller adjusts itself by changing the width (length) and frequency of the pulse sent to the battery.
The PWM controller is more suitable for small solar systems. It provides a low-cost solution, usually used when the solar cell temperature is between 45°C and 75°C.
MPPT solar controller:
The MPPT charge controller extracts maximum power from the PV module by forcing the PV module to operate at a voltage close to the maximum power point. It is designed to adjust its input voltage to utilize the maximum power output of the solar array, and then convert this power to provide varying voltage requirements. The input voltage is changed by using a DC/DC converter.
The MPPT controller does this through an adaptive algorithm that follows the maximum power point of the solar panel/array and then adjusts the input voltage to maintain the most effective power of the system. When the solar cell temperature is low (below 45°C), the performance advantage of the MPPT controller is very obvious. They are more efficient than the PWM controller xi. The MPPT controller is the best solution for high-power systems.
No one of these two controllers is better than the other, and the choice depends on personal needs. Xindun PMW solar controller 10A-200A, MPPT solar controller 10A-100A, welcome to consult.
