Solar Power

Solar Power technology converts solar radiation from the sun into usable electricity. Different solar power technologies are currently used around the world.

There are heliostats that focus acres of sunshine onto a small point, raising its temperature to over 5,000 degrees Fahrenheit. This is hot enough to generate high-pressure steam and turn a powerful turbine. This is an example of concentrating solar-thermal power (CSP). CSP is mostly employed at the infrastructure-scale.

Photovoltaics (PV) are the foundation of consumer-level mobile and residential solar power. They are economical enough to compose infrastructure-scale solar farms as well.

At the consumer level, a PV cell can generate as little as 1 Watt of power or less (such as the familiar PV cells atop older handheld calculators). Modern residential panels sitting atop homes generate about 350 Watts each when the sun is shining directly overhead. Smaller 100 Watt panels are commonly affixed to RV roofs or carried in handheld carrying cases for recreational purposes.

A manufactured photovoltaic cell will generate electricity at a certain voltage and amperage.

Let’s say a 100 Watt panel specifies that it generates 5 amps of current. Because it is a 100 Watt panel, and because Watt = Amperage * Voltage, it is implied that it must produce this electricity at 20 Volts (Because 5 Amps * 20 Volts = 100 Watts). So, it is a 100 Watt panel producing 5 Amps of current at 20 Volts.

It is common to connect solar panels together on the same circuit to increase the power generated in the circuit. A group of panels connected together is called an array of panels.

There are two ways to connect solar panels together: in series and in parallel.

In series, panels are “daisy-chained” together so that they form a single “loop” of circuit:

When panels are connected this way, in series, the total voltage produced is the sum of the individual voltages. The total amperage produced is the mean (or average) of the individual amperages (i.e. if the amperages of each panel is the same, the total amperage is the same of one individual panel).

In parallel, all of the positive (+) terminals are connected to one another, and all of the negative (-) terminals are connected to one another:

When panels are connected this way, in parallel, the total voltage produced is the mean (or average) of the individual voltages; the total amperage produced is the sum of the individual amperages. 

Series arrays can be “mixed” with parallel arrays. For example, you can create two different arrays of two panels connected in series. Then, you can join these two arrays together in parallel. It can be a bit of a challenge calculating the voltage and amperage produced. 

Sometimes, it is necessary to problem-solve and figure out which array is suitable for your power station. If your power station has a voltage input range of 60 V – 150 V, and a maximum solar array wattage of 1500 W, how should 10 x 100 W panels be arranged to feed the power station? Check out Solar Power Stations to learn more…