How to wire a Solar Cell into an Electrical Circuit?





The role of solar cells, in other words the main parts of the solar power panels, is to absorb photons and convert them into electrons. We already know that activation of electrons produces electricity.

The electricity produced by the solar cells cannot be used directly in everyday electronic devices because of the difference in voltage. Most of the solar cells sold today have a 6V - 12V - 24V output, whereas electrical appliances function with a mains voltage requirement of 115V - 240V AC input voltage. For this very reason the energy produced by solar cells cannot be connected to any system without using an agent electronic device.

Regulation of the Voltage of Solar Cells

As mentioned above, DC (direct current) has to be converted to AC (alternating current) which is used in network structure and is convertible. The device used for this purpose is called an Inverter.

An inverter is a device that converts a direct current with a specific voltage to alternative current. In the image below you can see how voltage is converted by an Inverter.
Dc to AC Inverter Graphs

Electrical Circuit Connection Options

1.) Direct Connection: Some home electronics need 12 - 24V DC voltage, although this is quite rare. It is possible to connect solar power panels to these devices. However, it is important to be aware that the output power solar energy cells provide is unstable. The calculations are generally done as 1000W solar power/1m2 with °90 Angle. However, this is not the case for all day. A decrease of performance and voltage occurs in early mornings and at sunset. In the diagram below you can see the amount of energy acquired depending to the angle of the sun.

Solar Radiation Diagram Hourly

In the above mentioned situation, what is required to connect the solar cells to an electronic device is to stabilize the voltage with the help of a battery, or by preparing an electronic regulation circuit. You should know that the regulation circuit cannot equalize the power while raising the voltage of the regulation circuit.

2.) With the Help of Inverter: In this phase the solar power panels are connected to the inverter module and the inverter outputs are connected to the inputs of the device that we want to use. What we have to pay attention to is that both the inverter output and device input has the same levels of voltage. There is another point you should pay attention- the drop of voltage applied to the input of the Inverter will cause a power loss as we mentioned above in the previous item. For this reason, the specific solution is to attach a battery unit to the solar panel.

Simple Inverter Image

The Connections of an Electric and Possible Problems

The main problem when connecting solar cells to electric circuits is voltage inconsistency. We talked about it above and offered some solutions. Now let’s move on to other possible problems and solutions.

Question: How can I connect the system without risking the solar panels if the circuit is using a different source?
Answer: In this kind of scenario you should isolate the solar cell system and the electric circuit with the help of diode. We ensure the protection of test current by connecting the solar cell’s one end to a diode and other end to the electric system. Otherwise, an inverse current would pass through to destroy the solar cells.

Question: I have a number of solar cells with different power and voltage; can I connect them all to the same electric system?
Answer: the most important thing that you should know is that you can connect two devices with different voltages in series and raise the voltage. However, you cannot do this by shunting. The basic rule of shunt is that the devices must have similar voltages. Therefore you have to connect the solar cells that have similar voltage. If you just want to raise the voltage then you can connect them in series. We will soon bring out a detailed study on this.

Question: Is there any possibility that the solar cells could harm electric circuits?
Answer: It can definitely harm the circuits. Any connection that is made recklessly or miscalculated, may harm the electric circuits.

Question: Are the variety and structure of the cables used in interconnection important?
Answer: Although not as important in smaller frames, the variety and structure of the cables are quite important in larger frames. A 200W panel, whose output voltage is 12V, has 17A output current. For this reason, the cable you chose should resist heavy currents. Imagine you are using 10 panels at the same time, in this case the output current would be around 170A and you have to choose the cable for transferring this kind of current carefully.

Dictionary of Technical Terms

  • Inverter: It is the device used to change AC voltage to DC voltage.
  • Electron: It is a particle that enables voltage generation in accordance with its speed in metals and it carries current. It moves from (+) --> (-).
  • Diode: It is a particle that lets electrons go over it in a one-way direction. In other words, it has (+) and (-) poles and it stops the transition of electrons.
  • Solar Cells: These are the most important parts of the Solar Panels. It is a chemical mechanism that converts reflected photons into electrons.

You now have the information required on how to connect solar panels to electrical circuits. In upcoming articles we will discuss series connection and shunt with illustrations.

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