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is a small but essential element of any solar electric panel system. It prevents batteries from getting overcharged and also prevents them from getting discharged through the solar panel array during nighttime. In short, the main purpose of the solar charge controller is to properly feed your deep cycle batteries and protect them in the long run. It is also used in off-grid and hybrid off-grid applications to regulate power input from PV arrays. They are also known as solar charge regulators.
Working of a Solar Charge Controller
When you decide to install a solar charge controller you should connect and disconnect in the following order-
Battery to the controller
PV array to the controller
Electrical load to the controller
The solar modules catch sunlight which converts solar power into DC electric power and then delivers it to the charge controller. It then regulates the amperage and voltage which is finally delivered to the loads. Any excess power is delivered to the battery system so that the batteries can well maintain their state of charge and don’t get overcharged in the process.
Types of Solar Charge Controller
There are two main types of solar charge controllers-
Pulse Width Modulation (PWM) controllers are smaller in size and operate at battery voltage. These controllers are used with arrays that can match the battery voltage. Sometimes, a PWM controller can be the right choice for you since it is less expensive, especially with small module configurations, and in warm climates. In a PWM controller, array voltage is pulled down to battery voltage and it generally operates below Vmp.
Maximum Power Point Tracking (MPPT) controllers use the latest technology and operate at the maximum power voltage. These controllers can operate at higher voltage and lower array currents. Since MPPT uses the latest technology, it can harvest more energy. MPPT controllers convert an excess input voltage into amperage and it operates at Vmp. It is mainly suitable for large module configurations that have a lower cost per watt. It also offers more boost than PWM during cold weather conditions and when the battery voltage is pretty low.
Applications that Use Solar Charge Controllers
Solar charge controllers are used in the following applications-
Oil & Gas sites
Residential sites
Lighting
Mobile homes, RV Caravans, and boats
Rural electrification
Telecommunications
Security or surveillance
Mining
Traffic/railroad signaling,
Environmental monitoring
Researchers are also using to incorporate the concept of harnessing solar energy to generate power in vehicles also. Due to this reason, solar powered cars are trending these days. People have understood that there is a need to converse resources and protect the environment. Solar powered cars are not very popular and they have some shortcomings but they will soon pick up pace in the world.
Protections for a Solar Charge Controller
Solar charge controllers should include environmental and electronic protections like-
Automatic recovery without fuses
Wide operating temperatures
Events like a short circuit, overload, reverse polarity, high voltage, high temperature, and nighttime reverse current.
Temperature fold backs
In a nutshell, the Solar charge controller that you choose should be able to support the power requirements of your loads, PV current, battery voltage, and voltage inputs. You should choose the best charge controller depending upon the climate, choice of modules, and price.