MPPT solar charge Overcharge maintenance
The basic function of solar controller
Understanding the role of solar controllers in the entire PV system and its basic functionality is a great help to our choice of solar charge and discharge controllers and how the PV system works.
One: the role of solar controller
The most basic role of solar intelligent manipulator is to maintain the battery from overcharge or over discharge. Overcharge may cause the battery in the electrolyte vaporization, resulting in problems, and the battery over discharge will cause the battery premature failure.
Second: the basic functions of solar controller:
1, overcharge maintenance: the charge voltage is higher than the maintenance voltage, the active shutdown of the battery charge, then when the voltage dropped to the holding voltage, the battery into the floating charge situation, when the float is lower than the recovery voltage, The
2, over discharge maintenance: When the battery voltage is lower than the maintenance voltage, the controller active closed output to maintain the battery from damage; when the battery recharging, but also active recovery power supply.
3, the load over-current and short-circuit maintenance: load current exceeds 10A or load short circuit, the fuse fuse, replace the sustainable use.
4, over-voltage maintenance: When the voltage is too high, the initiative to close the output, maintenance of electrical appliances from damage.
5, with anti-charging function: the use of Schottky diode to prevent the battery to the solar battery charging.
6, with anti-lightning function: When the lightning strike time, the varistor can prevent lightning, maintenance control device from damage.
Solar controller in accordance with the technology to points, generally divided into PWM type controller and MPPT type controller, used in the family off-grid small system how to choose, which is a lot of the initial design of off-grid small system engineers must consider the issue. Is selected PWM or MPPT controller, which is the size of solar energy and battery voltage has a great relationship.
A: If the solar panel operating voltage is 18V, power within 200W, the battery voltage is 12V, it is recommended to use PWM type controller. You can use LED display working status of the economic controller, you can also use the LCD display with a general-purpose controller. This will not only save the cost of off-grid small system, but also to achieve all the features.
2: If the solar panel voltage is relatively high, such as 50V or 75V, power, 300W or more, the battery voltage is 12V, it is recommended to use MPPT controller. The same power solar panel, the voltage is small on the small current, on the contrary, the voltage is small on the current, which greatly improves the efficiency of charging, the same solar panels, the same sunshine time, MPPT controller than the PWM controller efficiency Increased by about 30%. But the cost is high.