How to choose a controller for solar panels? Controller for a solar battery with your hands

The transition to alternative energy sources has been going on for many years, covering different spheres. Despite the attractiveness of the concept of obtaining free energy, in practice it is not easy to implement. There are both technical and financial difficulties. Nevertheless, in the case of small projects, alternative energy supplies justify themselves. For example, a controller for a solar battery allows you to use free power for electrical appliances, even at home. This component regulates the battery, allowing optimum use of the generated charge.

What controller parameters should be considered?

First of all, one should start from the total power and input voltage of the system, under which the controller is selected. That is, it is the capacity of the battery or battery pack that should not exceed the product of the system voltage by the output current of the control device. And the controller for the solar battery is selected from the calculation of the voltage in the discharged battery. In addition, a 20-percent margin for stress in the event of increased solar activity should also be envisaged.

Also, the controller is calculated in the ratio of the input voltage. This value is strictly regulated for the same cases of anomalous radiation activity. In the market, the controller for a solar battery is presented in different forms, each of which assumes its own specific characteristics of the described characteristics.

PWM Controller Selection Features

The choice of this type of control device is characterized by a simple approach - the future user needs to determine only with the optimal short-circuit current in the used module. There should also be some stock. For example, if the current of a 100 W solar generator stably functions with a short-circuit current of 6.7 A, then the controller must have a rated current of about 7.5 A.

Sometimes the discharge current is taken into account. It is especially important to take into account when operating controllers with load control function. In this case, the choice of the controller for a solar battery is made in such a way that the discharge current does not exceed the same nominal value in the control device.

Features of selecting MPPT controllers

This type of controllers is selected according to the power criterion. So, if the maximum current of the device is 50 A and the system operates optimally with a voltage of 48 V, the peak power of the controller will be about 2900 W, taking into account the added insufficiency potential. And here one more aspect is important. The fact is that the voltage of solar generators can be lowered in cases of their discharge. Accordingly, and power can fall by a significant fraction of a percent. But this does not mean that it is possible to make a discount on the performance of the controller itself - its power capacity should cover the limiting values.

In addition, in the question of how to choose a controller for solar cells such as MPPT, one should also take into account the characteristics of the radiation emitted. On the surface of the earth, the intensity of sunlight adds another 20% to the capacity of the battery infrastructure. Such phenomena can not be called a rule, but even as an accident they should be envisaged in calculating the power of the controller.

How to make the controller on its own?

A typical version of a self-made controller involves the use of a modest set of elements. Among them will be a transistor withstand current up to 49 A, a relay-regulator from the car, a resistor of 120 kΩ and a diode element. Then the relay is connected to the battery, and then the wire passes through the resistor to the gate of the transistor. During operation of the relay-controller, the positive signal must open the gate, and the current from the module of sunlight will pass through the legs of the transistor into the battery.

If a universal controller for a solar battery is made by oneself with the expectation of eliminating spontaneous consumption of accumulated energy, integration into the diode system will be mandatory. At night, it will create a backlight for the solar panel , eliminating the additional power consumption of the module.

Can I do without a controller for a solar battery?

Before giving an answer to this question, it is necessary to remember what the controller's function is in the solar module. With its help, the owner can autonomously control the process of charging the battery pack at the expense of light energy. If there is no controller, then the process of filling up with energy can occur until the boiling point of the electrolyte. That is, without the means to control the interaction between the solar panel and the battery, you can not do. Another thing is that the controller for a solar battery can be replaced with a voltmeter. When the peak values of charge and voltage are detected, the user himself can stop the process by disconnecting the battery module. This approach, of course, is inconvenient compared to automatic control, but in the case of a rare use of the system, and he can justify himself.

Conclusion

Manufacture of solar controllers and other components for this kind of modules are now being handled by many companies. This segment is no longer considered separate and specific. In the market, these components can be purchased for 10-15 thousand rubles, and good quality. Of course, a self-made controller for a solar battery with budgetary resistors and automotive electrical components will cost several times cheaper, but it can hardly guarantee the required level of reliability. And the moment of stability of work and safety is especially important in the operation of solar panels, not to mention the battery. If the solar module is successfully equipped with a high-quality controller, the owner can count on automatic accumulation of electricity without the need for intervention in the generation process.