Solar lights are a fantastic way to save energy costs, by using free and natural sunlight to generate electricity. On a bright, sunny day, the rays of the sun generate nearly 1,000 watts of energy per square meter of the earth's surface, which is more than enough to supply the electricity needs of the average home or office. Solar lights can harvest that free energy during the day, using it to charge built-in rechargeable batteries. At night, when the sun goes down, these lights can come on automatically, casting light and spending the energy they accumulated during the day.
However, if you live in a climate known for being rainy or overcast, you may wonder if, or how, solar lights can charge if it isn't a sunny day. The answer may surprise you.
How to Charge Solar Lights Without Sun
So there are several ways to charge solar lights without the direct rays of the sun. Here are a few:
Charge with indirect sunlight
Even on a cloudy day, the rays of the sun penetrate the clouds and illuminate the earth, casting light. That light can charge solar lights and solar panels, because the solar cells are extremely sensitive to light. Although charging won't be as fast or efficient as on a sunny day, solar lights will still be able to harvest energy from the light of the sun.
Charge with incandescent light
The light emitted by many indoor lightbulbs is sufficient to charge solar lights. If necessary, you could expose your lights, or just the solar cell and battery assembly, to normal household lighting in order to charge them. Of course, brighter, more direct light will be a faster and more effective way to charge solar lights, so placing them directly beneath a bright indoor light will speed the process.
Charge with LED lights
LED lights have the benefit of not only potentially being very bright, but also of being very energy efficient. Solar lights can easily be charged with LED lights, even battery-operated ones, like LED flashlights. LED lights are themselves often battery-powered, and have the benefit of being able to go where ever your solar lights may be, in order to recharge them.
Charge with mirrors
If, for some reason, your solar light is placed in deep shadow, and needs more light from the sun in order to charge efficiently, it is possible to position one or more mirrors to reflect sunlight directly onto the solar cells. This isn't a preferred solution, because the sun moves fairly quickly in the sky, which may mean that such mirrors need to be frequently re-angled and re-positioned, it is definitely possible, and is a method that uses no energy and no cost.
While it may seem counter-intuitive to use an electrical light to charge a solar light, it's possible to take advantage of any available light source to charge solar lights without sun.
How Do Solar Cells Work?
Firstly, let's remember how light works. Light is a unique element in our universe, because it is made of small packets called photons, but these photons move through the air in waves rather than in straight lines. So light has the both properties of mass, in which photons have weight, and can impact other particles and bounce off of them, and the properties of energy, in which photons travels in wavelengths rather than straight lines. Nothing else we know of behaves in quite the same way.
Solar cells take advantage of this unique property of light. To make a long story short, solar cells work by creating a molecular structure in which not all the subatomic particles in the cell are bonded in pairs with their neighbors. When those un-paired particles are hit by a photon, they are easily “knocked out” of place in their molecular structure, and begin to move around looking for a new atom to attach to. These moving particles each have a tiny electrical charge, and the solar cells are polarized, so that these electrical charges all move the same direction, and the electricity can be harvested and harnessed for our use.
What this means is that solar cells generate electricity, not by any special specific properties of sunlight, but through the action of light photons from any source. Sunlight is preferred simply because direct sun beams have so much sheer volume of light, compared to most other sources, but all light emits photons and all light can be used to generate electricity from a solar cell. This is why a solar calculator, for example, will work when powered by an indoor desk lamp.
How to Charge Solar Lights Most Efficiently
The sensitive photovoltaic cells in a solar light will harvest photons from any light source, but obviously the more photons that the cells are exposed to, the greater the resulting electric charge will be, and the batteries will recharge more quickly. For the best results, place your solar lights in the clear path of direct sun, rather than in the shade. Remember also that the angle of the sun's rays changes, not just during the course of the day, but, unless you live on the equator, it also changes over the course of the year. It may be necessary to angle your solar panels differently in the winter than in the summer, to account for the changing position of the sun during the seasons.
Solar lights using modern technology are incredibly reliable and efficient, harvesting energy from the sun all year long, even in cloudy and rainy weather, and generating light when needed.
They are also easy to recharge with any light source, even when the sun is hidden in the clouds. They create light all year long, with no negative environmental impact and no additional cost. It's a marvelous technology that provides tremendous benefits to people, their homes, and their energy bills. Use these tips to recharge solar lights without sun, and enjoy light when and where you need it, for free.