How Do Solar Lights Work?

Whether it’s for decoration or for function, being able to regularly illuminate an area without having to wire something is absolutely fantastic!

Solar lights have provided the average homeowner with so many easy to use options, that it’s no wonder their use has grown exponentially.

Yet despite the growing popularity of these lights, most people don’t know just exactly how they work.

Solar lights work when their 4 main components – the solar cell, the battery, the light source (LED) and the triggering sensor – all operate correctly.

## Note ##

It should be understood that the term ‘solar light’ is actually quite broad, referring to any light (generally outdoor) that is powered by the sun. Within this broad meaning, are two distinct categories – decorative and functional.

These two categories have different requirements and as such will have some degree of variation in the 4 main components. However, the core concept, for both categories, remains the same.

Solar Cells For Solar Lights

Arguably, the most important part of a solar light is the solar cell. This is the component that provides the power for your light, allowing a user to operate the light virtually anywhere there is sunshine.

One of the unique variations, previously mentioned for solar lights, can be found in what type of solar cell is actually being used.

  • Decorative Low Watt – In low watt situations, such as pathway solar lights, it is not uncommon to see Amorphous (Thin Film) solar cells. These type of solar cells have, historically, been cheaper to manufacture but are generally less efficient.
  • Decorative/Functional High Watt – Solar lights that have higher power demands will generally employ a Crystalline type of solar cell. Examples of this would be motion detect spotlights.

For an in-depth look at these two types of solar cells and their relationship to solar lights, check out: ‘Do Solar Lights Need Direct Sunlight?

Batteries For Solar Lights

Battery technology is an amazing field of science where ground-breaking discoveries are happening at an incredible pace. Admittedly, it can be very hard to keep up with things.

But, as it stands at the time of this writing, lithium-ion batteries dominate the solar light market; both for decorative and functional groups. This is because of their enhanced ability to store energy in all temperatures and their superior cycle rate – meaning they can charge and discharge more frequently without loss to overall performance.

What you will find, however, is a general size difference in batteries between low watt and high watt applications. It is this battery size that determines how long and how bright your solar light will illuminate.

For more on this, check out, ‘Can You Use Normal Batteries In Solar Lights?

## Note ##

When shopping for solar lights, be sure to look at what type of battery is included with your desired light.

There are some solar lights available for purchase that utilize regular batteries. However, it should be noted that the customer reviews for lights with lithium-ion batteries, tend to be much higher and with greater volume. So keep this in mind when shopping.

Solar Lights And LED’s

There is no doubt that LED’s (Light Emitting Diodes) have brought the science of illumination a great step forward as they generally use only a fraction of the energy required by their ‘old school’ filament counterparts.

Much like the transition from oil lamp to light-bulb, our lives have benefited from this new technology as it allows us to do more. Let’s be honest, the idea of the average home having lighted pathways or motion response illumination, even 50 years ago, would have sounded like something from ‘A Space Odyssey 2001.’

But yesterday’s daring dream is today’s online purchase.

Solar lights are largely dominated by the use of LED’s, greatly because of their low energy requirements.

However, there will be a difference’s in what type and how many LED’s are employed in your solar light, according to design requirements.

For example, our pathway solar lights have just one small LED that emits a ‘warm’ color of white. In contrast, Aootek’s best seller motion detect security solar light, boasts 120 LED’s that blasts out an ‘ultra bright’ light.

Solar Light Operating Sensor

Regardless of whether your solar light engages whenever it gets dark or it has a motion detect capability, chances are it has what is called a photoresistor.

Very simply put, a photoresistor changes the resistance to electron flow according to light levels.

So for example, imagine an electrical circuit with a photoresistor as part of the loop. As long as the photoresistor receives an adequate amount of sunlight, electron flow through the circuit is relatively uninhibited (think of it as ‘all clear’ signal).

But as the level of sunlight decreases, the photoresistor begins to ‘resist’ and electron flow begins to slow. Eventually, the ‘all clear’ signal disappears and your solar light knows it is time to engage.

This is why your pathway lights turn on at night, as the ‘all clear’ signal has disappeared.

This is also why motion detect lights do not engage during the day, as the ‘all clear’ signal is present, despite any motion that might have been detected by the security light.

## Note ##

Depending on design, it is very likely that the motion detect sensor in your motion detect solar light remains off (in order to conserve power), while the ‘all clear’ signal is present.

Solar Lights & How It All Works

As mention before, there is an enormous range of options and capabilities for outdoor solar lights. Personally, it find it enjoyable to ‘lurk’ in the online stores – it’s a sort of year round Christmas Catalog for grown-ups.

But regardless of the diversity of performance and capability, all solar lights work on four main concepts.

  • Step 1 – A solar cell produces power when exposed to sunlight.
  • Step 2 – This power is then stored in a battery.
  • Step 3 – Sunlight conditions are monitored via a photoresistor (think all clear signal).
  • Step 4 – When designed parameters have been met, power is released from the batteries and sent to the LED’s where illumination then occurs.

While the advances in engineering things like solar cells and batteries continue to move rapidly, it is most likely the these four main steps will remain for some time to come.

Understanding these four steps can go a long ways in helping you choose a solar light that best suits your needs.