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How Long Do Solar Lights Take to Charge? Here is the Answer!

Written by Eddie B. Robinson / Checked by Justin Tucker

how long do solar lights take to charge

How long do solar lights take to charge? Many people, especially first-time solar-powered device owners, ask this question. I understand why you would want to know.

Learning a solar light’s charging time can help you optimize the solar panel’s light-gathering performance and the battery’s power storage capabilities. It will also be easier for you to think of ways to make solar light charging more efficient.

In general, it takes around 6 to 10 hours to charge solar lights. Continue reading for more details.


How Long Do Solar Lights Take To Charge

Before I answer this question, let us take a few minutes to freshen up our knowledge of solar lighting systems.

Your solar light has three essential components: a solar panel, a battery, and the light bulb. Other electrical components work in between these main parts to make the system more efficient.

The solar panels contain light-sensitive cells that catch, absorb, and collect sunlight or any other light source. Electrical devices in the solar panels convert the light energy into electricity, conveying it to the battery.

When the solar panels can no longer collect light (as what happens at night), a sensor automatically sends stored electricity from the battery to the solar light bulb and illuminates it. When the device senses that the solar panels can collect light energy again, it cuts electricity to the bulb, turning it off.

Technically, the battery stores the electricity generated from the solar panels. Thus, determining how long it takes to charge the solar lights can be hit or miss.

Under ideal conditions, a solar light system should reach a fully charged status after six hours of continuous, direct sunlight exposure. The lamp should stay operational for about eight to ten hours.

If charging solar lights first time, most experts recommend exposing solar lights to direct sunlight for a minimum of eight hours. I find ten hours sufficient in most cases.

Unfortunately, not everyone has the luxury of a 12-hour daytime. Some regions have shorter days, especially during the winter. I know of a place in Alaska where the town does not get to see the sun for more than two months.

If you want a definitive answer, you can charge your solar lights for 8 continuous hours under the sun.

What Factors Can Affect A Solar Light’s Charging Capabilities


We know that a solar light’s charging performance depends on several factors, including climate conditions, solar panel angle inclination, battery type and capacity, panel cleanliness, and panel efficiency. Let us discuss these considerations one by one.

Solar Panel Efficiency

Solar panels integrated into solar lighting fixtures vary in their energy conversion efficiency. A product’s solar efficiency describes its ability to convert light energy into electrical power. For example, a 20%-rated solar panel can convert 20 percent of its collected solar power into usable electricity.

We must realize that photovoltaic cell technology is far from perfect. No solar panel can convert 100% light energy into 100% DC electricity, at least not yet.

If your solar light’s panels have a lower efficiency rating, it takes a longer time to charge the system than a unit with a high-efficiency rating.

Climate Conditions

Your solar lights can charge fast in the first year because the solar panels are still brand new. Sadly, they tend to lose about 0.8 percent of their light-gathering capabilities every year. That is why you can expect your solar lights to collect only 99.2% of sunlight in the second year and only 92% after a decade.

If you also factor in the solar panel’s efficiency (ability to convert light power to electricity), you know that it increases your system’s charging time. So, if it takes you about six hours to charge your solar light in the first year, you may need seven hours of charging by the second year.

Climate conditions can also impact the amount of light your solar light can absorb and turn into electricity. For example, if you live in a place where it is always cloudy, the amount of sunlight collected by your system will be lower than in a sunny location.

Solar Panel Cleanliness

People living in sunny Florida may think they can charge their solar lights quickly. However, if you do not take care of your solar lights, it would still be impossible to charge your solar light fast. Dust and particulates on the solar panels can reduce their light-gathering capabilities.

Solar Panel Angle Inclination and Position

Did you know that your solar panels should also have an inclination angle of 25 degrees for optimum solar-gathering performance? However, your location can also be a crucial factor.

For example, if you live in the lower states where the sun is higher in the sky, your solar panels should have a 20-degree angle tilt. If you live in New York and other upper states, a 45-degree tilt is ideal because the sun is lower in the sky.

Positioning your solar lights in the right direction also improves their charging performance. It is always a good idea to place the solar panels facing south if you live in the northern hemisphere. People south of the Equator should consider directing their solar panels to the north.

Battery Capacity and Type

The battery in your solar light can also affect your system’s charging time. In general, lithium iron phosphate rechargeable batteries are quick to charge, and others. On the other hand, a NiCd battery charges faster than a NiMH dry cell. However, the latter type often has a higher capacity than the former.

There is also the battery capacity to think about. For example, the Tenergy NiCd 1000mAh battery may require a longer time to fully charge than the GEILIENERGY NiMH 600mAh dry cell for solar lights.

Can I Estimate My Solar Lights’ Charging Time


If you want to get a rough estimate of your solar light’s charging time, you can divide your lithium-iron phosphate battery capacity by your solar panel’s wattage rating. You can then multiply the product by two.

Let us say you have an 1800 mAh, 3.2-volt lithium iron phosphate running your solar lights. Suppose your solar light panels can generate 2.5 watts of electricity.

First, we convert mAh to ampere-hours by dividing 1800 mAh by 1000 to get 1.8. We then multiply 1.8 Ah by 3.2 volts to get our battery’s capacity of 5.76 watts (amperes x volts). Next, we divide 5.76 by 2.5 (solar panel watts) to get 2.3 watts. The last step involves multiplying 2.3 by 2 to get 4.6.

For our example, you can charge your lithium iron phosphate battery-run solar lights in 4.6 hours.

However, I must reiterate that this formula assumes you have the ideal charging conditions. If not, you can expect the charging time to be longer.

How Can I Ensure Faster Solar Light Charging Times

You can ensure shorter charging times by positioning your solar lights in the correct direction and cleaning the solar panels. Dirt and any particulates can collect on the solar panels, extending the charging time.

It also helps to get solar lights with high-efficiency solar panels to start with. A high-performance rechargeable battery can also improve solar light charging times.


There are no straightforward answers to the question, how long do solar lights take to charge. You can have your system ready within six hours of continuous exposure to direct sunlight if you observe ideal charging parameters. First-time charging should always run for at least eight hours.

While charging times can fluctuate every day, you can always observe a few things to hasten your solar light’s power-regeneration process. Cleaning and correct positioning of the panels are simple ways you can improve charging times.

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