The Output From Solar Panels

Solar panels can convert energy from the sun into electricity.

Solar panels convert sunlight into electricity without any moving parts. They are a collection of silicon cells. Each cell only produces about 1/2 volts, but a typical panel contains 36 cells wired together, which can be used to charge a 12-volt battery.

Configuration

Typically, photovoltaic solar electric panels are measured in watts. A watt is voltage times amperage. Since solar panels are made up of a number of cells, the voltage and the amperage can be changed depending on how the cells are configured. Whether configured in a series or parallel, the total wattage will be the same.

Cost Per Watt

There are different types of photovoltaic solar panels. Some panels are more efficient than others. So, the less efficient varieties require more surface area to provide the same output, in watts. Generally, the less-efficient panels cost less than more efficient ones, making it difficult to compare price per panel. The way to compare how much a panel costs is in dollars per watt. So if one panel costs $400 and outputs 100 watts, it would cost $4 per watt ($400 divided by 100 watts). If another panel costs $600 but puts out more than 150 watts it would actually be cheaper on a cost-per-watt basis.

Watts Per Square Foot

Individual panels come in a variety of sizes, number of cells, efficiencies and wattages. A 47-inch-by-21-inch panel may produce only 80 watts, while a 62-inch-by-31-inch panel may produce 185 watts. The key is the cost per watt, unless you have very limited space for mounting the panels. In which case, you may have to pay more per watt, to get a higher-efficiency model, so you get more watts per square foot.

To calculate watts per square foot, divide the total wattage by the number of square feet in the panel. For instance, a 2-foot-by-5-foot panel is 10 square feet. If it outputs 100 watts that is 10 watts per square foot (100 watts divided by 10 square feet). Modern panels typically output around 13 watts per square foot.

References

• Free Sun Power: Basic Tutorials: Solar Panels
• Solar Panel Store: Lumos Solar Panels