How Long Does It Take to Charge a Solar Powered Speaker?

Written By: | Last Updated on: June 27, 2023

Solar-powered speakers are the new rage in the world of portable audio technology, blending sustainability and sound quality into one neat package. 

With a dependency on the sun’s energy for power, these eco-friendly gadgets raise the question – how long does it take to charge a solar-powered speaker? 

The answer depends on several factors such as battery capacity, solar panel efficiency, and sunlight intensity.

But we can say that with optimal sunlight conditions, they may take about 4.3 hours to fully charge. 

In this guide, I’ll walk you step by step through the process of calculating the charging time of a solar-powered speaker, taking into account all the factors that influence it.

Key Takeaways

  • The charging time of solar speakers depends on battery capacity, solar panel efficiency, and sunlight intensity
  • Charging time is calculated by dividing the battery capacity by the solar panel’s power output
  • Ideal conditions allow a solar speaker with a 2,000mAh battery and 20% efficient panel to fully charge in approximately 4.3 hours
  • Actual charging times can vary based on weather conditions and the sun’s angle

What Is the Working Principle of Solar-Powered Speakers?

The working principle of solar-powered speakers is primarily based on the concepts of solar energy collection, conversion, and storage.

At the heart of this process is a set of solar panels incorporated into the speaker. 

These solar panels are made of photovoltaic cells, which have the ability to capture sunlight and convert it into electricity. 

This conversion process relies on the principle of photovoltaics, where the energy from photons (light particles) is used to generate a flow of electrons, resulting in an electrical current.

Each solar cell is essentially a sandwich of two slices of semiconductor material, typically silicon, treated to have different electrical properties. 

When sunlight hits the solar cell, it excites the electrons in the negatively charged layer, causing them to jump to the positively charged layer. 

This movement of electrons from one layer to another generates an electric current.

However, the solar panels don’t power the speakers directly. 

Instead, the electrical energy they generate is stored in a battery for later use. 

This energy storage capability allows the speaker to function even when sunlight isn’t available, like during the night or in indoor settings.

What Are the Key Factors Influencing Charging Time?

1. Battery Capacity

The capacity of a battery refers to the total amount of energy it can store and is typically measured in milliamp hours (mAh) or watt-hours (Wh).

Just like a water tank with a larger capacity takes longer to fill up, a battery with a larger capacity takes longer to charge. 

The larger the battery’s capacity, the more energy it can store, but it also requires more time to fully charge. 

This principle applies whether the charging method is solar, USB, or another type of charger.

For instance, a solar-powered speaker with a battery capacity of 2,000mAh will take twice as long to fully charge than a speaker with a 1,000mAh battery, given all other conditions (like sunlight intensity and solar panel efficiency) remain the same.

2. Solar Panel Efficiency

Solar panel efficiency refers to how well a solar panel can convert sunlight into usable electricity. 

It’s a measure of the panel’s ability to capture sunlight and effectively turn it into the electrical energy necessary to power the speaker or charge its battery.

Solar panel efficiency is determined by the type of material used in the solar cells, the configuration of the cells, and the technology employed in their design and manufacturing. 

It is usually expressed as a percentage, with higher percentages indicating more efficient panels. 

For instance, a panel with an efficiency of 20% converts 20% of the sunlight that hits it into electrical energy.

When it comes to charging solar-powered speakers, a more efficient solar panel can capture and convert more sunlight in less time, thus reducing the overall charging time. 

This means that speakers with more efficient solar panels will generally charge faster than those with less efficient panels, given the same light conditions.

However, it’s important to note that solar panel efficiency can be affected by various external factors, including the angle and intensity of the sunlight, temperature, and even dust or dirt on the panel’s surface.

 Thus, maintaining your solar panel and positioning it to receive maximum sunlight will help ensure it operates at its maximum efficiency, reducing the charging time of your speaker.

3. Sunlight Intensity

Sunlight intensity, solar irradiance, and peak sun hours are interconnected factors that substantially influence the charging time of a solar-powered speaker. 

Sunlight intensity is the amount of solar energy received per unit area, typically measured in watts per square meter (W/m²). 

More intense sunlight provides more energy for the solar panel to convert into electrical energy.

Peak sun hours further refine the concept of sunlight intensity. 

This term doesn’t refer to the longest daylight hours but to the number of hours in a day when the sunlight’s intensity is high enough to allow solar panels to generate their maximum rated power. 

In more technical terms, peak sun hours refer to the number of hours when solar irradiance averages 1,000 watts per square meter.

These hours are crucial for charging solar-powered speakers as they represent the period of the day when charging can occur at the fastest rate. 

In most locations, peak sun hours usually occur around midday when the sun is at its highest point in the sky. 

However, the exact number and timing of peak sun hours can vary depending on the time of year, geographical location, local weather, and the angle of the solar panel relative to the sun.

The more peak sun-hours a location has, the faster a solar-powered speaker will charge. 

For instance, a speaker placed in a location with 6 peak sun hours could theoretically charge twice as fast as the same speaker in a location with only 3 peak sun hours.

 Consequently, knowing the peak sun hours in your area can give you a more accurate estimate of how long it will take to charge your solar-powered speaker.

4. Weather Conditions

The optimal weather for solar charging is clear and sunny, as solar panels can harness the most energy under these conditions. 

This is primarily because solar panels depend on sunlight, and the more direct sunlight they receive, the more electricity they can produce.

Cloudy or overcast weather can significantly reduce the amount of sunlight reaching the solar panels, thereby lowering the charging rate. 

While solar panels can still generate some power in cloudy conditions, the efficiency is much lower compared to a bright sunny day. 

For example, on a heavily overcast day, a solar panel might produce only 10-25% of its rated capacity.

Rainy or snowy conditions can also have a significant impact. 

The rain itself does not block sunlight as much as cloud cover, but prolonged periods of rain often come with heavy cloud cover. 

Snow can cover the solar panels and block sunlight completely, rendering the panels unable to generate electricity until the snow is cleared.

Temperature also plays a role in charging efficiency. 

While you might think that hotter weather would be better for solar charging, solar panels actually work less efficiently at higher temperatures. 

This is due to the properties of the semiconductor materials used in the panels. 

On extremely hot days, the increased temperature might reduce the panel’s power output, making it take longer to charge the speaker.

5. Angle and Direction

The angle and direction of the solar panel on your speaker can influence how much sunlight the panel can capture and consequently convert into electrical energy.

The angle at which sunlight hits the solar panel is crucial. 

When sunlight hits the panel directly (at a 90-degree angle), the panel can absorb the most light and generate the most power. 

If the sunlight hits at an angle, the panel won’t be able to capture as much light, and power generation will decrease. 

For this reason, the solar panel’s angle might need adjusting throughout the year to align with the sun’s changing position in the sky.

The direction the solar panel faces is equally important. 

For the maximum energy yield, solar panels should generally face the equator. 

In the Northern Hemisphere, this means facing the panels south, while in the Southern Hemisphere, panels should face north. 

If the panel is not pointed in the optimal direction, it may not receive the maximum possible sunlight, resulting in a longer charging time.

While adjusting the angle and direction may not always be possible with portable solar-powered speakers, it’s worth considering when setting up your speaker. 

Even small changes in positioning can make a significant difference in charging efficiency, helping your speaker’s battery to charge faster and perform longer.

How to Calculate the Charging Time of Solar-Powered Speakers?

Step 1 – Determine Battery Capacity

The first step in calculating the charging time of solar-powered speakers involves determining the battery’s capacity. 

The battery capacity is the total amount of energy the battery can hold. It’s typically measured in milliamp-hours (mAh) or watt-hours (Wh). 

You can usually find this information in the speaker’s specifications or product manual.

Let’s say, for instance, your solar-powered speaker has a battery capacity of 2,000mAh

This figure means the battery can theoretically deliver 2,000 milliamps of current for an hour, or 1,000 milliamps for two hours, and so on. 

Remember, a battery with a larger capacity can power your speaker for a longer time, but it also requires more energy (and thus more time) to fully charge. 

So, once you have the battery’s capacity, you’re one step closer to determining how long it will take to charge your solar-powered speaker.

Step 2 – Assess Solar Panel Efficiency

The second step in calculating the charging time of solar-powered speakers is to assess the efficiency of the solar panel. 

You can usually find the solar panel’s efficiency in the speaker’s product specifications or manual.

Solar panel efficiency is typically given as a percentage. 

Suppose your solar panel has an efficiency rating of 20%.

In this case, it means the panel is capable of converting 20% of the sunlight it receives into usable electrical energy. 

So, for every 100 units of sunlight, the panel receives, it will generate 20 units of electricity.

Step 3 – Measure Sunlight Intensity

The third step in calculating the charging time of solar-powered speakers is to measure sunlight intensity, also known as solar irradiance.

You can use online calculators like the PVWatts Calculator from the National Renewable Energy Laboratory (NREL) to estimate the sunlight intensity in your area.

If you live in California, for example, you might experience an average sunlight intensity of around 172 W/m² or 5.83 hours per day.

Step 4 – Calculate the Charging Time of Solar-Powered Speakers

Finally, we reach the last step, where we bring all our previous information together to calculate the charging time. 

For this, we’ll need to use a bit of mathematics, but don’t worry; it’s quite straightforward!

First, let’s look at our gathered data:

  • Battery capacity: 2,000mAh
  • Solar panel efficiency: 20%
  • Average sunlight intensity in California: 172 W/m²

Before proceeding with the calculations, we need to convert the battery capacity from milliamp-hours (mAh) to watt-hours (Wh). 

Most solar panels’ power output is typically measured in Watts, and converting to the same unit will ensure an accurate calculation.

Assuming that the battery voltage is the common 3.7V for small electronics, the conversion is as follows:

Battery Capacity in Wh = Battery Capacity in mAh * Voltage / 1000 = 2,000mAh * 3.7V / 1000 = 7.4Wh

Next, we calculate the power output from the solar panel. 

Let’s assume the solar panel’s area on the speaker is 0.05m², a typical size for small solar panels used in portable devices.

Using the formula:

Power Output = Sunlight Intensity * Solar Panel Efficiency * Solar Panel Area, we find:

Power Output = 172 W/m² * 0.20 * 0.05m² = 1.72W

Now we can calculate the charging time. Using the formula:

Charging Time = Battery Capacity / Power Output, we get:

Charging Time = 7.4Wh / 1.72W ≈ 4.3 hours

So, in ideal conditions, it would take approximately 4.3 hours to fully charge the speaker’s battery using solar power. 

Remember, these calculations are based on ideal conditions and actual charging times can be influenced by many factors such as weather, the angle of the sun, and more, as we discussed earlier.


As promised, we’ve covered the fundamental aspects that determine the charging time of a solar-powered speaker. 

We’ve explored factors such as battery capacity, solar panel efficiency, and sunlight intensity, and even delved into some simple maths to bring it all together.

And if you ask for my advice, it would be to turn all your appliances and gadgets to solar power wherever possible. 

Not only does this help conserve the environment by reducing our carbon footprint, but it also cuts down on your electricity bills in the long run.

Do you still have questions? Leave a comment and our team of solar experts will be more than happy to help you out.

Kami Turky
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