Solar Panel Basics

 
Living off the grid doesn’t mean you have to live like a Mennonite. Modern solar panels are an improving renewable energy source that offers an excellent alternative to grid electricity. Solar panel systems are a popular choice due to the relatively low maintenance requirements and the long lifetime of its components. Since there are no moving parts, there is little chance of mechanical failure  in a solar panel system and it should continue to produce power for at least 25 years.

How Solar Panels Systems Work

Solar panels are are made up of solid-state semiconductor devices called photovoltaic (PV) cells that absorb the suns energy and coverts it to into direct-current (DC) electricity. These cells are made from two very thin silicon wafers, one with a positive charge and the other with a negative. When exposed to light, an electric charge is generated which runs through a grid of electrical contacts distributed across the panel. This charge is then sent through a junction box on the back of the panel and emerges as DC electricity.

This DC is then sent to a charge controller that regulates the amount of current the panels feed into the battery bank preventing over charging. The controller also blocks any current leaking from the batteries back into the array, preventing battery drainage. The batteries chemically store electrical energy sent from the panels until it’s needed. From the batteries the DC current is sent to an inverter that turns it into AC so that it can be used by all your electrical devices.

Solar Panels come in 3 types. The most efficient are mono-crystalline panels but they are also the most expensive. They are ideal for smaller areas such as residential houses because you can fit more watts into less space. The second type of panels are poly-crystalline. They are less expensive and less efficient than mono-crystalline panels and are probably the most popular panel for smaller setups or places where space is not an issue. The third type of panels are thin-film. They are the least expensive but also the least efficient. The best feature of these panels are that they are light, flexible and easy to install.

How Many Solar Panels Do I Need?

To determine how many panels you need, you will first need to figure out how much power you will need. Think about all the devices you will need to run and how many hours a day they will be on. Then check the wattage rating on these devices. For instance a light bulb rated at 25 watts would require 25 watts of power for every hour that it is on. Now multiply each devices wattage rating by how many hours each will be running to get an idea of how much power you will use.

Solar panels are rated the same way as your appliances except that it describes how many watts it will produce at peak sunlight rather than use. So lets say your power requirements for a day is 2400 watts and you live in an area that receives 6 hours of peak sunlight a day. If you divide 2400 watts by 6 you get 400 watts. This means you would need 4 100 watt solar panels to meet your energy needs.