With good foundation, you can better understand other materials (or salesmen) in the future.

First, you need to know that there are different wavelengths present in sunlight.

You can use a prism to split sunlight into various colors, which is a manifestation of its wavelengths. (Remember those science experiments?)

In some solar application, it’s the infrared component of sunlight that’s utilized. In others, only the visible light is useful. Modern engineering tries to marry different technologies to harvest as much of the (visible and invisible) spectrum as possible to enhance solar panel efficiency.

Second, you need to know how sunlight interacts with matter.

Sunlight can be absorbed, transmitted, scattered or reflected. It is the material’s property that determines how light behaves.

When light is absorbed, its energy is transformed into heat. In some cases, it is changed into electricity. All solar energy systems depend on this property — absorption.

When light is transmitted, very little energy is lost. It simply goes through the material with very little attenuation.

Scattering occurs when light interacts with molecules. Light radiates in many different directions with different intensity in such cases.

Reflection occurs when light is bounced back. Shiny, smooth surfaces are better reflectors than dark, matte surfaces.

There are no perfect materials. Thus there is no such thing as a perfect conductor or a perfect absorber. An index is always used (in physics) to identify how well each material conducts or absorbs light.

If you are interested in solar water heaters, you must also know how heat interacts with matter.

Some materials can conduct heat pretty well while a few others restricts the flow of heat. Solar heaters make use of materials that can absorb solar radiation well. They trap solar energy and turn it into heat.

Once this is done, other materials are used to conduct and distribute heat so it can be used to warm up water (or air). In order to keep heat from escaping, a heat insulator must be used.

Putting these materials together, we can create a phenomenon known as the greenhouse effect. Glass is a good material for this purpose. It can transmit light pretty well and is also a good insulator of heat.

This is why your car, when parked under the sun for a while, can get so hot inside.

If you are interested in generating electricity, you must know about photovoltaic cells. They are commonly known as solar cells. They absorb sunlight to produce electricity.

Common PV cells consist of two layers of thin semiconductor sandwiched together. They are made of highly purified silicon. These are the same material found in transistors and microchips.

This construction forms millions of p-n junctions that can generate electricity when exposed to light. When photons (sunlight) hit each p-n junction, their energy is absorbed. This cause electrons to break free from its orbit.

Free-moving electrons are made to flow in a particular direction under the influence of an electric field. Such electron movement produces electricity.

If you need to know more about solar energy, solar panels and energy conservation, more information is available as you browse through the categories on the right.

Continue Reading:

1. Pool Solar Panels
2. What Are Solar Heaters, How They Work And What They Are Used For
3. Important Facts And Properties of A Solar (PV) Panel You Must Know About (Part 1 of 3)

If you’ve ever built DIY solar panels of a considerable size, you’ll probably come across this important component — the charge controller. The role of a charge controller is to regulate the charging voltage on the batteries.

When sunlight gets brighter, solar cells produce more voltage. Excessive voltage may cause over-charging which may damage your batteries. You’ll need this component if you want to store excess electricity from your solar energy panels.

Many modern charge controller units have a 3-stage cycle:

1. Bulk Phase – During this phase, the charging voltage gradually rises to approximately 14.4 to 14.6 volts (to charge a 12V battery). It is at this stage when charging current is maximum.

2. Absorption Phase – Voltage is maintained at the bulk level for a specified time. As the battery is charged up, current tapers off gradually.

3. Float Phase – After the absorption phase, voltage is lowered to about 13.4 to 13.7 volts (float voltage) and batteries draw a very small, maintenance current until it goes through the discharge cycle.

There are several different types of charge controller to choose from — some with fanciful LCD displays and others with battery temperature monitor. If you are building your first solar power generator, it may be more practical to buy basic ones to begin with. After you’re more acquainted with these components, you’ll have more knowledge to get the most out of more advanced charge controllers. Most multi-stage, Pulse Width Modulation (PWM) types of charge controllers will do great, really.

Continue Reading:

1. Solar Energy Panels For Big “Toys”
2. Sizing Your Solar Energy Panels – Part 3
3. How To Build A Solar Panel Charge Controller