So, many of us are planning to use solar energy for the lightbulbs. The question is, do solar lights need direct sunlight? While the answer might be obvious, a closer examination of solar-powered systems will reveal things many of us fail to appreciate. As it turns out, you can power up any solar device with other light sources – not only the sun.
Join me in this article to understand solar light systems and appreciate how we can optimize these lighting fixtures, even without direct sunlight.
Does A Solar Light Need Direct Sunlight to Work?
Solar-powered devices, such as solar lights, need light to convert into electrical energy. One example of a light source is direct sunlight.
Some experts believe solar power is a misnomer because it does not rely only on the sun’s power. It works with other light sources as well.
It is worth mentioning that sunlight is free. There are no monthly bills to worry you, no complicated setups to think about, and no gadgets to tinker with. You only need to position the photovoltaic cells in direct sunlight, and the photovoltaic effect takes care of everything else.
Of course, there are other more technical reasons why sunlight is the best power source for solar lights.
However, the fact remains that any light source can power a solar panel, albeit not as efficiently as direct sunlight.
How Do Solar Power Systems Work?
Let us start by clarifying something about solar power. The word ‘solar’ indeed comes from the Latin word ‘sol’ or ‘Solaris,’ translating into ‘sun.’ That is why many believe solar systems can only draw their power from sunlight.
However, at the heart of any solar power system is the photovoltaic cell. In1839, Edmond Becquerel discovered the photovoltaic effect or the conversion of light energy to electricity. Unfortunately, it was only in the 1960s when modern man began applying Becquerel’s discovery for practical applications.
Today, photovoltaic cells continue to evolve, increasing light energy-conversion efficiency with each innovation.
When light (also called photons) strikes the photovoltaic cells, the photons stir up the atoms in the cells. The reaction causes the movement of electrons, producing electricity. After all, electricity is nothing more than the flow of electrons along a conductor.
In the case of solar light, the resulting conversion of light energy into electrical power lights up the lighting fixture.
Can a Light Bulb Charge a Solar Panel?
Solar light has several essential components: a solar panel, a lighting fixture, a solar battery, and a circuit board. The solar panel contains the photovoltaic cells we discussed above, allowing the solar light to gather as many photons (or light energy) as possible for conversion into electricity.
The solar panel gathers and generates electricity, which the circuit board stores into the battery. When there is no light, a switch in the circuit board automatically sends electricity from the battery to the lighting fixture.
Hence, any light source can provide photons to the solar panel, making it possible to charge a solar panel with an LED light, incandescent bulb, compact fluorescent light, halogen bulb, or any other light source.
However, I would like to reiterate that using these light sources is less efficient than direct sunlight. You will need batteries or electricity to power on an ordinary light bulb.
There is also the issue of light waves. The sun produces various light waves, including ultraviolet light and visible light. Unfortunately, not all lighting fixtures can match the sun’s expansive light waves. You can try UV light, but heat and radiation will be principal concerns.
If you need to charge your solar light using an ordinary bulb, it would be best to place the solar light directly under the artificial light source. The distance should be as close to the solar light as possible (some people recommend at least 20 inches), and the exposure time should be as long as possible.
It is worth mentioning that ordinary light bulbs take longer to charge a solar panel than direct sunlight. For example, charging the solar light panel under the sun can take six to eight hours. Powering the solar panel with artificial light can take 12 to 16 hours.
In general, light bulbs with a higher wattage rating can charge a solar panel faster than low-wattage lighting fixtures.
Will Solar Lights Charge in Shade?
Solar panels continue to gather light energy even on cloudy days. However, some photovoltaic cells are more efficient in solar energy collection in such situations.
Amorphous solar panels collect more light energy in low-light conditions than monocrystalline or polycrystalline solar panels. These solar panels also ensure a more complete charge on cloudy days.
Hence, you can still charge your solar lights even on cloudy days or in the shade if you have amorphous panels.
Unfortunately, these solar panels are less efficient than other panel types on bright, sunny days.
Can You Charge Solar Lights in the Winter?
There is light even in the winter, allowing you to charge your solar lights. However, like powering up the solar panels in the shade, on cloudy days, or with artificial light, it would be unwise to expect an efficiency similar to direct sunlight in the summer.
Two issues confront solar light owners in the winter. First, snow can cover the solar panel and obstruct sunlight from reaching the panel’s surface. Second, daylight hours are shorter in winter than in the summer, translating to more frequent and longer shadows.
It would be wise to clean the solar panels at least every three to four hours to prevent snow accumulation. It will also help to reposition the solar panels more frequently to avoid the shadows.
Do solar lights need direct sunlight? The answer is, of course, solar lights need direct sunlight to work efficiently. However, other light sources can also power up the solar panels where there is no sunlight, such as nighttime, cloudy days, in the shade, and during winter.
You can use ordinary light bulbs (incandescent, LEDs, fluorescent, and halogen) positioned as close as possible and exposed as long as practical to the solar light.