How do solar lights work? Figuring out the answer to this question isn’t the most difficult thing in the world (the information is widely available), but it does take a little bit of electrical and engineering background to make sense of the information. We’re not talking about a full, four-year degree here, but a little bit of high-school level science class would serve you well if you’re trying to understand how solar lights work.
In the paragraphs below, we’ll take you through some of the basics of how solar technology works in general. We’ll also explain how solar lights use light sensors and solar technology to keep your driveway illuminated at night. Finally, we’ll discuss how solar lights can be made to work even in environments that don’t seem ideal for the equipment.
How Do Solar Lights Work?
Before we can begin to explain how solar lights work in particular, we should explain a little bit about how solar, or photovoltaic, technology works. (Don’t worry, it’s not complicated.)
It all starts with the solar panel. In solar panels, two or more layers of silicon are sandwiched together. The top layer is “doped” with phosphorus to give it a positive electrical charge (extra electrons). The bottom layer is doped with boron, to give it a negative electrical charge (missing electrons). The top layer is exposed to sunlight which is comprised of energetic particles called “photons.” These photons knock loose electrons from the phosphorus-doped top layer of silicon and send them scurrying towards the junction between the silicon wafers. Conductive wiring gathers these electrons and sends them to batteries as electrical current, where they’re stored for later use as power.
Inverters in solar power systems convert that current from direct current (DC) in which the electrons flow in only one direction, into alternating current (AC) in which the electrons shimmy back and forth at periodic intervals.
Solar lights use the power stored in these batteries to operate. Along with the technology described above, solar lights have sensors that indicate how bright it is outside. When the brightness is above a certain level, the lights turn off and the attached solar panels begin to generate electricity in the fashion explained in the previous few paragraphs.
When the brightness falls below a certain level, the lights turn on and power is drawn from the batteries. The cycle repeats when it becomes bright enough again to turn off the lights and begin generating electricity once more.
As a final note, the above paragraphs are admittedly the “high-school” version of how solar technology operates. We’ve purposely omitted some of the more confusing details in order to keep the article accessible to as many people as possible, even if you lack a science or engineering background. For more information, feel free to consult with your friendly, neighborhood world-wide-web.
Do Solar Lights Only Work in Direct Sunlight?
No! It is certainly possible to use solar lights without direct sunlight. While bright, direct sunlight is the best way to make a solar light work, other methods will serve the same purpose if given enough time.
One might think that cloud cover is a death knell for solar-powered everything. One would be incorrect in that assumption. While direct, bright sunlight is the preferred way to regenerate a solar light battery, even indirect sunlight will allow a solar light to work. Remember when we said that photons knock the electrons off of the phosphorus-doped silicon atoms? That remains the case in indirect sunlight. There are just fewer photons to go around. In indirect sunlight, photons will still strike the solar panels, they will just do so less often and, therefore, regenerate the battery slower than direct sunlight would.
Artificial lighting, while much less powerful than sunlight, will charge a solar battery. This means you can take the solar light inside and place it near an LED or incandescent bulb and expect the solar light battery to charge, albeit quite slowly. The same principle that keeps the battery charging during periods of indirect sunlight holds true in this case. The indoor lights that illuminate our rooms utilize photons just like the sun. They will also knock electrons loose from the silicon atoms in the solar panels.
We should note specifically that both LED and incandescent lights will operate to charge a solar light battery. You do not need to seek out one over the other. Either will do the trick.
Many solar lights, both indoor and outdoor, come with alternate charging methods. Frequently, these are USB or wall outlet ports that allow you to plug the solar light into a USB charger, computer or wall socket to charge the internal battery. Use the opportunity whenever it is convenient to fully recharge the solar light by this method since it will typically be much faster than waiting for it to charge by solar panel, even in direct sunlight. Of course, if you purchased the solar light specifically to avoid using “on-the-grid” power solutions you may not wish to do this.
Hopefully, by now we’ve made the concepts of solar technology and solar lights a little bit more understandable. You should now be able to explain and understand how solar lights work and, more generally, how photovoltaic technology converts sunlight into electricity.
You can use solar technology in areas with comparatively little direct sunlight, short days, and extended cloud cover. You’ll simply need to be a little bit more intelligent about where and when to use your solar devices, and where and when to recharge them.
Learning how solar lights work, even without the sun, is not complicated or onerous. All you need is a little bit of indirect daylight, some incandescent or led bulbs, or an alternative charging solution, and you’ll be able to keep that solar light working for as long as you need.