Control of battery charging in solar systems

In conditions when fossil fuel reserves are steadily declining, and the need for it and the environmental damage is growing exponentially, the need to find new ways of energy supply. One of the key alternative sources is our Sun, the energy of the rays which can and should be used to produce electricity.

At the very basic solar system consists of the following components:

• Solar panel. It is a rectangular module with a mirror surface that is used for receiving radiation and transforming it into electric current constant type. This process occurs thanks to the combination of a huge number of semiconductor elements;
• battery pack. Used as a source of stored energy, which is then distributed to household consumers in the required amount;
• Inverter. A Converter that transforms direct current coming from the terminals of the batteries to AC. At the same time changing the frequency and voltage;
• . The Executive unit that regulates the level of battery charge.

How does the charge controller?

This module is an intermediate, and its main role is reduced to the selection of the optimum charging of batteries. If it is removed from the overall circuit, is constantly arriving at terminals the current will eventually lead to uncontrolled growth of voltage on them. When the maximum battery values at 14.4 V, will start the reverse process from overcharging. As a result of boiling electrolyte in the banks, it will begin to evaporate, shortening the lifetime of the battery.

the main functions of the controllers include:

• Automatic selection of the charging batteries;
• Control the level of charge by disconnecting and connecting users;
• Do polarity on terminals
• Protection from termination of the network short circuit and soD.

Main types of controllers and their features

To date, there are three main types of control units battery charging solar systems:

• Tripping On/Off controllers;
• Blocks pulse-width modulation (PWM)
• Controllers maximum power point ( MPPT).

Most are simple On/Off control units. Their work is to disable the batteries when the voltage at the terminals of the indicator of 14.4 V. This is, of course, will protect your battery from overheating, but not the charge level will constantly stay at around a maximum of 70%. Such a process reduces the overall battery life.

Eliminated the point under charge in a more modern PWM type controllers that use the so-called PWM modulation of the charging current in the peak phase. When the voltage at the battery terminals reaches the maximum level, the PWM controller gradually decreases the current value. Supporting parameters such charge for a certain period of time, achieves full battery charge, and the efficiency of the system increase by a third.

the Most advanced are the MPPT type controllers that implement the principle of tracking the maximum power point. These devices allow you to use the charge voltage in the region of 17V, which is higher than the limit for batteries. The efficiency of these devices increases by one third, it is also becoming possible use of panels by reducing their light exposure almost in half.

Conclusions

Controllers PWM and MPPT types are an integral part of any solar system and hybrid solar-wind generators. They allow you to provide the optimal level of battery charge, increasing the overall efficiency of the generation and use of electricity.

Translated by "Yandex.Translate": translate.yandex.ru.