How Do Solar Lights Work

how solar lights work

Solar lights are just like the ordinary ones, the only difference is that they generate energy from the SUN without the use of any hard wires or complicated hardware.

All you need to do is to put them in a sunny spot and that’s it. They will automatically charge during the day and turn on to illuminate your home at night.

Further, solar lamps are one of the best ways to reduce your carbon footprint and help the environment.

For these reasons, many house owners all around the world started shifting towards this sustainable source of lighting.

In this article, we will answer one of the most asked questions: How solar powered lights work?

So without further ado, let’s jump right into it.

How Solar Lights Actually Work

Solar lights use sunlight to generate electricity and automatically trap this electricity inside batteries so they can work at night or cloudy days.

But how do solar powered lights exactly work?

Well, the whole solar energy idea is based on the Photovoltaics theory.

In simple words, sunlight stimulates atoms which cause them to gain and lose electrons and as a result, a flow of electrons occurs AKA electricity.

To have a better understanding on how solar lights actually work, let’s take a quick look at the main components of solar lights.

1. Solar Panels (Photovoltaic Cells)

This is the main part of the photovoltaic system and it’s mainly made of semiconductors and special chemicals.

Semiconductors such as Silicon (sand) are the main component of all microelectronic devices such as mobiles, computers, and all electronic devices.

To understand how the solar light cells work, first you need to understand how semiconductors work.

What makes semiconductors such special materials is that they have two charges: 

  • Negative charges: These are the electrons in the conductive level and they are attached/connected to the atom via magnetic force.
    Think of the atom as a big magnet and electrons as small coins.
    When the coins gain enough energy to break free from the atom force (you pull them) they become free electrons.
    You can use these free electrons to generate electricity as electricity = flow of free electrons. In other words, when electrons moves from point A to point B, then there is electricity in AB
  • Positive charges: Semiconductors are almost stable (inactive) materials.
    For example, Silicon has 4 electrons in the conductive level and it’s more than happy with it.
    However, when the silicon atom loses an electron due to heat, light, or whatever reason, the electron leaves a gap also known as a Hole, which makes the atom pretty upset.
    In order to please the atom, this hole acts as a positive charge and it tries its best to fill the gap by attracting electrons to stabilize the atom, which in return generate an electron flow AKA electricity

How do solar light panels generate electricity?

When sunlight enters the cell it provides the electrons enough energy to break free from the atoms and pushes them towards holes (positive poles).

Diagram of how solar panels work

Once you attach a good electrical conductor like iron or copper between the 2 poles of the semiconductor you have a closed circuit and the electricity can be used to power the load (LED light). 

In simple terms:

  1. Sunlight stimulates atoms (powers up electrons)
  2. Atoms lose electrons (electrons break free)
  3. Electrons move (holes and positive poles attract electrons)
  4. Electricity current occurs due to the movement of electrons
  5. Electricity power the LEDs
  6. And let there be light!

2. Batteries

You don’t need a full section to teach you how batteries work, they are just batteries man, DUH!

Seriously there is nothing to say, all you need to know is that the solar cells are attached to rechargeable batteries and they charge them during the day, so they can operate at night when there is no sunlight.

3. Sensors

Oh wait, you might be wondering how can solar lights turn on automatically at night?

Well, they use something called SENSORS.

Solar lights contain photoreceptors (light sensors) on the top of the panels. These sensors “sense“ sunlight and when it gets dark (sensors detect no light) they turn on the lights automatically.

There are different types of photosensors. However, there are the 3 commonly used ones:

  1. Light Sensor (photocell): This sensor is responsible for activating the lights when it’s dark out there. In other words, when this sensor detects darkness (absence of light), it automatically turns on your solar lights at night
  2. Lux Sensor: This sensor controls how dark it has to be outside before activating the light. In other words, it senses light intensity and you can easily adjust it to you preferred settings
  3. Passive Infra-Red (PIR): This sensor can be found in motion-detecting and security solar lights and it mainly senses the heat. Without overwhelming you with such technical details, this sensor will activate the light when it detects someone near and it can be also adjusted

4. Charge Controller (Battery Regulator)

The Charge Controller has 2 functions:

  1. Protects your solar lights from overvoltage
  2. It prevents batteries from overcharging

That’s all to it really, it protects and improves the performance of the battery, which prolongs your solar light lifespan.

5. Inverter

All your home’s electrical sockets provide 240V. Yes, I am telling you that your big 146-inch tv and your phone charger are operating on the same voltage!

Well, not really, here comes the converter job. The converter lowers this high voltage so it can suit every device.

For example, your mobile charger has a built-in converter that lowers the default 240V to a usable 5V

Similarly, your laptop charger has an inverter that lowers the voltage to 20V, and so on.

But what does it have to do with inverters?

It’s the same thing. The only difference between inverters and converters is that the inverter raises the voltage while the converter lowers it.

6. Light Emitting Diodes (LEDs)

Our journey to the center of the solar lights ends with the LEDs. Don’t worry they aren’t just white flashy orbs. 

In fact, there are plenty of beautiful colors, types, and light intensities that will suit all your decorative purposes.

Last Words

As promised, we provided you with a full definitive guide on how solar lights work and their components.

In the end, we really hope you enjoyed this article and stay tuned for more awesome solar tips and tricks from Solar Energy Hackers.

Do you find this guide helpful? Do you have any questions or ideas to make this guide even better?

Please, let us know your thoughts in the comment section below.

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