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How to Charge Solar Lights Without Sun or with Little Sunlight?

Written by Eddie B. Robinson / Checked by Justin Tucker

how to charge solar lights without sun

Are you one of those people who wonder how to charge solar lights without sun or with little sun? Are you questioning whether you can charge solar lights indoor or not? You can count yourself lucky because of your natural curiosity. While it may seem absurd to charge solar lights with little to no sun, there are a few tricks you can perform.

In this how-to article, I will share with you several tricks to help you power up your solar lights even when the weather is not cooperating. Sounds great? Let us get to it then.


Things You Need for This Tutorial

Solar lights are marvelous pieces of engineering that rely on solar energy, lowering your electricity bill. Their low carbon footprint makes them a more environmentally-friendly solution to supply the modern home with electrical energy.

Unfortunately, solar power is not a 24-hour phenomenon. While there is heat on the Earth’s surface even at night, it is often insufficient to charge a solar light. That is why a lot of people ask for an alternative charging method for their solar lights.

Let us look at a few things you need to charge solar panels using a different source of light energy.

Knowledge of Solar Light Charging Process

Solar lights work by harvesting energy from direct sunlight. Solar cells respond best when there’s enough sunlight, converting the solar energy into direct current (DC) electricity, which is stored in solar batteries. The more light the solar panel receives, the more DC energy it produces and stores.

When there is no sunlight, a mechanism in the solar lighting system activates the solar light by directing stored electricity to the light fixtures.

As such, we can say solar lights charge by drawing energy and converting this to electricity.

Given this mechanism, it would be safe to assume that any light source can serve as an external power source for solar light. In theory, artificial light sources should be sufficient to ensure a fully-charged solar light.

Tools and Materials You Might Need, Depending on Your Chosen Method

Normally, you will need as much sunlight as possible to charge your solar lights. But since you’re probably charging your device on cloudy days and nights when visible light is nil, you will need a few materials to help you mimic, recreate, or redirect outdoor sunlight.


Objects with a reflective surface offer you a chance to charge a solar light even in cloudy weather. Mirrors work best in redirecting full sunlight. They allow your solar panel to gather as much energy as possible and recharge the batteries fast.

Size matters when choosing mirrors to bounce off indirect sunlight towards solar cells. The mirror should be at least twice as big as your solar-powered outdoor light.

Ideally, you will want to get a concave mirror because it can focus the light energy into the solar panels a lot better than a convex surface.

Artificial Lighting

Outdoor solar lights depend on sun rays for their energy. Since sunlight has a definite color temperature range, you can use different artificial lighting fixtures to deliver light energy to the solar cells.

Incandescent light is an exceptional choice because it produces low levels of UV radiation. Most incandescent bulbs have a color temperature close to that of direct sunlight, making them an excellent light source to charge solar lights at night.

You can also check out LED lights, which can have varying color temperatures from 2,000 to 7,000 Kelvin. Some LED lights come in the form of torchlights or emergency lighting fixtures. It should never be a problem sourcing an LED light.

While these solutions are less efficient than natural sunlight, they make excellent choices for people living in cold climates where the daytime is often shorter than nighttime. They are also suitable to use in cloudy weather.

You’ll also need a towel to clean your solar panels.

How to Charge Solar Lights without Sun or with Minimal Sunlight


Step 1. Clean the solar panels thoroughly.

Cleaning your solar lights’ photovoltaic cell panels is one of the easiest ways to ensure you can charge solar lights on a cloudy day.

Dust, dirt, grime, and other contaminants can reduce the solar array’s ability to collect sunlight, extending the time to charge solar batteries. Using batteries with insufficient charge can lead to problems in your system.

Always use a soft cloth or a microfiber towel in cleaning your solar panels. These products are gentler on the surface.

It would be wise to remove any dirt, rock, or other large particles from the panel’s surface. Wiping these off with a cloth can scratch the photovoltaic cells.

Pro Tip: Spray your solar panels using a gentle stream if you live in an area with frequent wildfires and sandstorms or plenty of pollen and dust. Take extra care not to introduce water into your solar system’s electrical components.

Step 2. Reposition your solar lights.

Everyone knows the sun moves from east to west every day and at different angles throughout the year, depending on our planet’s position relative to the sun. Unfortunately, your solar lights may stay in the same position all year round.

Positioning your solar powered lights can determine whether they get more sunlight or less sunlight. Ideally, you will want the solar cells to be perpendicular to the sun’s rays, forming a 90-degree angle.

Sadly, this procedure can be taxing because you will be mimicking the positioning of a sundial. It is essential to reposition the solar panels every hour, following the sun’s path.

Pro Tip: If you live in the northern hemisphere, start repositioning your solar panels facing the south before going west, east, and north. Do not place your solar lights under any shade or in an area cast by shadows.

Step 3. Reflect sunlight towards your solar lights.

If repositioning your solar panels is not feasible, using reflector surfaces should do the trick. Place a mirror under sunlight and angle it to reflect sun rays to your solar cells.

While this method of using indirect sunlight is not as efficient as following the sun’s position during the day, it might be your only recourse.

The trick is to use mirrors twice the size of your solar array. For example, if your solar cell measures two feet by one foot, your mirror should be at least four feet by two feet.

Similar to repositioning the solar cells, you will also move the mirror at different times of the day. It would be wise to remember that you want maximum light reflection.

I found an interesting Tech Insider video about a rotating mirror that follows the sun’s direction throughout the day.

Tip: Turn off your solar lights to optimize the charging process

You can charge your solar lights by not using them for several days, allowing complete charging for 72 hours. As such, if you are exposing your solar panels to direct sunlight for eight hours every day, you will need about nine days of complete solar light rest.

This method is what many solar industry experts call deep charging. You might want to look for alternative lighting during this time, such as using electric or battery-operated lighting fixtures.

You can perform this step once every month or two.

Steps To Charging Your Solar Lights Indoors


Step 1. Use incandescent bulbs.

You have several options to charge a solar panel with a light bulb. Incandescent lights are a popular choice. An incandescent bulb emits low levels of UV radiation and can also closely resemble the sun’s color temperature, visible light, and light intensity.

Some compact fluorescent light (CFL) bulbs come in daylight color temperatures, allowing them to mimic the sun’s color temperature of 5900 to 6500-degree Kelvin.


It is best to place solar lights close to the artificial lighting. Always use an incandescent light with a high wattage rating to hasten the solar panel charging process.

If you want to learn more about color temperatures in light bulbs, you can check out this video from Signify.

Pro Tip: For optimum results, expose your solar panels to artificial light for at least 12 hours.

Step 2. Use LED lights.

The second step to charging your solar lights indoors is by using LED bulbs. A great example of such devices is solar flashlights or torchlights with LED lamps.

The great news about these devices is that you can choose different LED color temperatures that closely mimic the sun’s color temperature. They are also more portable and only require batteries to run.


This method is so versatile that you can recharge your solar lights when camping, fishing, or during any other outdoor activity.

Pro Tip: Always expose your solar panels to a LED light for at least ten hours. The longer the light exposure, the better the solar-powered light charging.


Knowing how to charge solar lights without sun or charging solar lights indoors may sound impossible. However, we already know that it is possible to optimize your solar lighting system’s charge with or without sunlight.

I hope you found this tutorial helpful in maximizing your solar lights’ performance. I also hope you will share this with your family members, friends, and colleagues. You know, they might also be wondering if they can charge their solar lighting systems even without the sun.

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