How To Charge Solar Lights Without Sun: 3 Easy Tips

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This is our guide on how to charge solar lights without sun.

Solar power is clean, cheap, and bountiful – it’s no wonder there’s been a surge in demand for solar light panels and solar cell lights in recent years.

It’s also no surprise there have been massive improvements in solar cell technology.

But solar technology still has plenty of challenges to contend with, not least the challenge of how to capture the sun’s light energy on a cloudy day and during winter months.

If you are somewhat disappointed with the performance of your solar-powered lights and devices, this article is for you. Our team has road-tested various solar cell lights in different scenarios to determine how to charge solar cells without the sun.

If you’re clean and green, but you want more bang for your buck, read on and absorb our field test results.

How Do Solar Lights Normally Charge Up?

Though it may seem like it, it isn’t magic that makes your solar light glow at dusk; it’s crafty science! The main part of your solar lights is the photovoltaic cells and the battery. These can actually charge your solar lights without the sun.

The cell on top of a solar light is made from crystalline silicon (a semiconductor) and chemicals that contain negatively charged particles. When the sun’s light energy hits the cell, it excites the negative particles and pushes them into positively charged spaces.

With the electrons positively charged, they are then sent through connecting wires as DC current. This current is stored in a battery within the lights or in some dedicated solar batteries. The conversion of full sunlight to electrical energy happens throughout the day until the battery is fully charged.

Related: How Do Solar Lights Work?

Do Solar Lights Need Sun To Work?

Everybody wants to know if their amorphous solar panel can drive down their winter power bills or shrink their carbon footprint on a cloudy day. There’s some good news and some bad news.

The good news is that solar panels absorb “daylight” rather than “sunlight.” In other words, to charge solar lights without sun, they don’t have to be under direct sunlight. It also means you can charge solar lights on overcast days and during the winter months.

Although you can charge solar lights without sun, the charging will be far less effective! It might take many days and weeks to charge solar batteries in your solar lights in the short days of winter.

The short answer is yes, you can easily charge solar lights without sun. But remember, any photovoltaic cell will be more efficient when angled directly at the sun.

Charging Solar Lights Indoors

Our team has experimented with every conceivable way of charging indoor and outdoor solar lights. We wanted to find alternative ways to charge solar lights, such as incandescent bulbs, LED light sources, and standard electricity.

You might be wondering why this is necessary. Solar lights work by using the sun, so why mess about with artificial light?

Whether you live off-grid or you prefer to charge solar lights in your garden to reduce your carbon footprint, there are times when you get stuck. You might need your solar flashlights after dark or need your garden lights to work a bit longer at a late-night event.

Use Incandescent Bulbs

These are the standard bulbs you use for indoor lights and lamps. In recent times they have become less popular as they are energy heavy and wasteful. But many people still use them. Surprisingly, they are one of the better ways to charge solar lights indoors.

Like the sun, incandescent lights produce lightwaves that a photovoltaic cell can capture and turn into electricity. In theory, this means that you can charge your solar devices with incandescent light bulbs indoors. The trouble is they are much less efficient.

We left a solar light beside an incandescent light bulb for two hours. The solar light started completely dead, and after two hours, it was partially charged.

Use An LED Source

LED lights are tiny – they’re the little red and green ones you find on electronic devices. So how can these power your solar lights indoors?

Actually, LEDs come in different sizes, and you probably have them in your vanity lights, accent lights, and decorative lights. If your eco-minded, you probably opt for LED light every time since they draw less power. That makes them cheaper too!

LEDs also produce lightwaves on the visible light spectrum to charge solar-powered lights in the same way as incandescent light bulbs. Additionally, LED lights produce long infrared waves and ultraviolet waves that are also found in sunlight.

Charge With Electricity

If you’re solar-minded or live an off-grid lifestyle, you probably don’t want to use electricity to charge your solar lights or devices.

You would be using power to create power. That defeats the purpose, right?

There’s no question that this method is an “inefficient” way to use your solar lights, but it isn’t “ineffective.” There are times when you’re stuck, and you need a full charge in your solar devices. Under certain circumstances, it makes sense to use mains power.

Today, many solar devices have options for mains charging or a DC charger for the car – this is very useful for emergencies.

Related: Why Do Solar Lights Have An On/Off Switch?

Charging Solar Lights Outside Without Sunlight

Solar panels have improved significantly in the last five years. It’s partly due to improvements in technology, but also more funding and higher demand for them.

In the last five years, solar panel cell technology has increased its efficiency by 15-20%.

This is great news for eco-minded people and anyone wanting to reduce their annual power bills. But it’s no good having an efficient solar panel cell if there isn’t any sunlight, right?

Maybe not – read on to find out how to charge your outdoor solar lights.

Do Solar Lights Charge When It’s Cloudy?

Solar panels are smart; they are designed to capture the many lightwaves found in direct sunlight. This includes lightwaves from the electromagnetic spectrum., such as visible light, infrared light, and ultraviolet light.

In cloudy weather, these lightwaves are still around! Anytime you have daylight, you are in the presence of sunlight on the electromagnetic spectrum. And so are your solar panel cells.

A photovoltaic cell doesn’t need direct sunlight to charge. They can absorb the sun’s energy from their surroundings. That’s good news if you have a low-level outdoor light source or you want to use your solar lights in winter.

Keep Solar Panels Out Of The Shade

Although solar panels use daylight to charge and don’t necessarily need direct sunlight, that doesn’t mean you can leave them in the shade.

Take our word for it – we tried it, and the results were pretty dire.

When you’re working with low-level light, you need to maximize the panel’s access to the electromagnetic spectrum. When the panel is in the shade, it doesn’t matter how bright the sun is; it will be like trying to charge your lights inside the house.

Consider where your lights are set up and how much shade they’re likely to get as the sun moves across the garden. If you can, collect the lights and place them in a sun-rich area throughout the day.

Regularly Clear Snow From Panels In The Winter

When the days become shorter in the winter months, it’s time to pay extra attention to your solar panels.

There is not only a reduction in daylight at this time; you might also receive snowfall that prevents your panels from working effectively.

If you have cloud cover, snowfall, and a reduction in daylight hours, your solar cells won’t have nearly enough solar energy to work with.

Always remove snow to charge solar panels with a soft brush – this applies to solar panels for generators and to solar cells for small garden lights. Scratches prevent the cell from absorbing solar energy and reduce its energy output.

Use Mirrors To Reflect Light Towards The Panels

If you want your solar panels to be as effective in winter as they are in summer, it calls for some serious innovation. Not to mention some labor-intensive tactics.

One excellent way to increase energy absorption during indirect sunlight is to use mirrors. You can buy mirrors specially made for your solar panels or find ones in a Homestore that are the correct dimensions.

You want mirrors that are about 20% larger than the solar panel to maximize your solar capture.

The reason mirrors are labor-intensive is because they need to be repositioned as the sun moves. More sunlight counts in the winter.

Final Thoughts On How To Charge Solar Lights Without Sun

Solar panels and solar light of all kinds use a photovoltaic cell to turn the sun’s radiation into electrical power. This energy is stored in a battery and used after dark.

Sometimes people buy solar lights and wonder why they don’t work. They don’t come on at night and seem to be a waste of money. The problem will be the solar cell’s access to a light source.

Surprisingly, you don’t need more sunlight to charge your solar cells, only daylight. You can also charge them using artificial lighting such as incandescent bulbs, LED lights, and mains electricity. However, only mains electricity is a reliable way to charge your solar lights.

In general, you want to make sure your solar cells are clean – clean them regularly with a soft-bristled brush – and make sure they aren’t in the shade throughout the day.

You can further boost their solar capture by using mirrors to reflect more daylight onto the cells.


Will solar lights charge in the shade?

Depending on the efficiency of the solar panel, you can charge your solar lights in the shade! Solar power panels need daylight and not as much sunlight to charge. But most solar cells won’t charge well in the shade.

Do you charge solar lights on or off?

If your solar lights are switched on during direct sunlight, they will still charge. However, it is far more effective if you switch them off. Turn them off to fully charge the solar lights.

How do you charge solar lights for the first time?

To charge solar batteries, you need to charge them fully before their first use. This full charge should be via direct sunlight or indirect sunlight, rather than artificially through the mains.

Will solar lights charge under artificial light?

Yes! You can charge solar lights with no sun. They will charge under an artificial light source such as an incandescent bulb and LEDs. However, these solar power sources won’t charge your solar cells quickly, and it’s less efficient than mains power.

Photo of author

Eric Thomas

Eric is the founder of the Simple Solar Living team and serves as our CEO & Chief Solar Officer. He is passionate about solar powered products and DIY solar projects, and took part in the Solar Energy Technician program at Bryan University. Eric is committed to sharing the benefits of going solar and is a steadfast advocate of clean renewable energy.