One of the main challenges of photovoltaic technology is learning how to charge solar lights without the sun. You’ll be happy to learn though that it is possible, if slightly less efficient, to do so. Read on below to find different strategies for keeping your solar lights charged in the absence of direct sunlight. We’ll discuss the basics of how solar lights operate, whether it’s possible to keep those lights on in the extended absence of direct, bright sunlight, and what conditions you can exploit to keep your solar batteries charged for as long as possible. (Trying to learn how to fix solar lights when they break? Click that link to find out!)
How Do Solar Lights Even Work?
Before we can explain how to charge solar lights without sun, 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 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 detail 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.
Can you Charge Solar Lights Without Sun?
Yes! It is certainly possible to charge solar lights (like these solar lanterns) without direct sunlight. There multiple methods to do this. Although they are not as efficient as bright sunlight would be in charging the battery, they will all work to regenerate the charge located in the battery and bring the solar light back to life in a pinch.
How to Charge Solar Lights Without Sun
1. In indirect sunlight
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 work to charge the light. 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, charge the solar light battery slower than direct sunlight would.
2. Use artificial lighting
Artificial lighting, while much less powerful than sunlight, will charge a solar light battery. This means you can take the solar light inside and place it near an LED or incandescent bulb and expect the solar light batter 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.
3. Use the alternative charging method
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 charge the solar light (perhaps by using one of these solar power banks) 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.
You may have thought at one point that solar light technology was only useful in reliably sunny areas with very little cloud cover. That’s an understandable and common misconception. While these areas benefit particularly acutely from the use of solar technology, constant, direct, and bright sunlight is not a necessity to make solar technology work. (Unless you’re powering particularly heavy-duty technology like solar generators.)
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 charge them.
Learning how to charge solar lights without 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 battery charged for as long as you need. (Or click here to learn how to keep your solar lights clean!)