Off-Grid Solar System Basics
1. Solar panel (PV module)
Solar panels or modules are made of solar cells. A solar cell is an electrical device that converts the energy of light directly into electricity (DC) using the photovoltaic effect. The process of conversion first requires a material which absorbs the solar energy (photon), then produces electrons, which the flow to an external circuit. Silicon which is a key component used in the production of PV modules, is one such material that uses this process.
2. Charge controller
Charge controllers may also be called solar regulators. These components regulate the amount of energy that is passed on to the battery bank. Some charge controllers / solar regulators have additional features, such as a low voltage disconnect (LDV), a separate circuit which removes loads (energy draws) when the batteries become overly discharged, and additional circuitry that eliminates potential overcharging; both of which reduce the life of the battery banks.
3. Battery Bank
This stores the energy produced by the solar panels allowing it to be used on demand – day or night, sunny day or cloudy. Properly engineered off-grid systems ensure that there is enough energy produced and stored to provide ample average power throughout the power producing and non-producing cycles. When it comes to solar battery banks, each is designed for a specific charge or discharge level. Some are manufactured wet cells, manufactured sealed or gel cells, each coming with their own set of pro/cons. Costs of battery banks varies significantly, however battery performance and service life are a key consideration in any solar system installation.
An inverter’s basic function is to “invert” the direct current (DC) output (the power from the PV modules) into alternating current (AC). AC is the standard used by all commercial appliances, which is why many view inverters as the “gateway” between the photovoltaic (PV) system and the energy consuming loads.