For homeowners, the cost of installing a residential solar system has fallen dramatically over recent years. More and more people are putting solar panels on their homes to offset their electricity bills. How do they work? What are differences between the different sizes of panels? What are important factors homeowners should know about them? This article will cover these questions, and will give you an in-depth look at one of the most important (and obviously, necessary) components in a solar electric PV system.


Basic Principles of Photovoltaics

The most common terminology used in regards to a home solar electric system is “solar panel”, which basically means a module or collection of solar cells. Each solar cell uses sunlight to make electricity. This collection is wired in series and parallel circuits to produce a desired voltage and current. The output of the module is decided by the surface area and the cell efficiency of each cell in the module. A panel is one or more cells wired together. An array is a group of panels wired together to produce an optimal voltage and attached to a mounting structure.

How Solar Electricity Works in Modules (AKA No Moving Parts Needed)
Solar modules collect and convert energy from the sun into electricity. The solar cells rely on the “photovoltaic effect” – which describes how certain materials can convert sunlight into electricity and causes current to flow between two oppositely charged layers. This creates electrical current. Electrical output is significant when modules are connected together as an array.

Two Different, Yet Popular Module Types
The main difference between modules is the material of the cell. The most common is crystalline silicon. Grown as a single crystal, it is known as mono or single-crystalline. Cast into an ingot of multiple crystals is known as poly or multi-crystalline. These two types perform similarly, however single crystalline cells are slightly more efficient than poly due to the poly-crystalline inter-grain boundaries within the cell. (SEI Design & Installation Photovoltaics, Section 5.2) (Amorphous silicon or thin-film is expensive to manufacture and is only about half as efficient as crystalline silicon cells.)

Each module has two terminals, positive and negative, but can be set up differently. Some modules have junction boxes with conduit holes and access where the wires connect. Some modules are “quick-connect”, meaning there are no junction boxes, but a male and female connector to accelerate the installation process.

Important Factors
PV modules and arrays are a reliable source of energy, but they must be properly designed and installed by professionals for the system to be reliable and effective. Curious about what size solar system you will need or the costs involved in installing a solar electric system? PPC Solar can calculate actual system needs and production with a free site analysis or no-strings-attached quote over the phone: 877-736-5896.

For more basic solar information, stay tuned for the next PV 101 blog installmentHow to Calculate Electrical Loads!


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