A basic solar system is made of 4 main components. These are solar panels, a charge controller, batteries and an inverter. These all work together to use the energy from the sun run your household appliances like a tv, radio or fridge.
Solar Panels – First let’s look at solar modules (also called solar panels). Solar Panels convert solar energy produced by the sun into electrical energy. Solar panels are made from smaller solar cells that are connected in series and put into a aluminium frame. For sake of simplicity a 90w solar panel like the one in the picture (above) will produce 90 watts of energy per hour if the sun is shining on it. In the Southern hemisphere we install panels facing north and usually on a roof where it gets the most direct sunlight in a day.
Charge Controller – The solar charge controller is connected to the solar panels and is installed between the solar panels and the battery in a system. The primary role is to manage the charging of the batteries. It prevents the battery from over-charging and controls the rate of current and volts while charging. At night it also stops electricity flowing from the batteries to the solar panels. There are two types of chargers on the market. PWM & MPPT. I’ll go into more depth in another post, for now just note PWM chargers are not as efficient in converting solar energy and is less expensive they work well on small 12V systems. MPPT is newer technology, a bit more expensive but has increased charging efficiency. MPPT chargers are usually used on systems above 1000w.
Batteries – Solar batteries are special deep-cycle batteries that provide storage for solar energy. They are not the same as the batteries found in cars, which were designed to provide high current for very short amount of time. The function of batteries in a solar system is to store solar power produced during the day so that that the power can be used at night to watch tv or put on lights. There are many types of battery technologies on the market. The most popular being lead-acid batteries and lithium Ion batteries.
Inverter – So far, every component in the system uses DC power. Panels generate DC power, the charger manages the storage of the DC power into the batteries. Most household appliances use AC (Alternating Current) like the power you get from a wall socket. Here in South Africa it is 220V AC (in some countries it can be 110V AC). The inverter’s job is to take the 12V DC power from the battery and convert it to 220V AC power so that your appliances can run.
These are the four main components of a basic solar system.
It is important to use the correct gauge wires in a solar system. The general rule is to keep wire runs as short as possible to avoid system losses. For a small 12V system I am using 6mm solar cable from the solar panels to the charger. Between the charger and battery I am using 6mm as recommended in the charge controller’s installation manual. From the battery to the inverter I am using 10mm. IT IS DANGEROUS TO USE THE WRONG WIRE GAUGE ON A SOLAR SYSTEM, THE CABLES CAN HEAT UP AND CAUSE A FIRE!
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