As a new, energy-saving, and environmentally friendly lighting solutions, solar street lights are now preferred by more and more governments for new roads or public lighting, and are now widely used in streets, parking lots, parks, residential communities, and other areas.

However, the market is flooded with a wide variety of solar street lights, and the performance difference between different brands and models is obvious, causing a big difference in product quality, with some being of inferior quality and deceiving consumers.

Therefore, when you, as a purchaser for a government project, choose solar street lights, you need to carefully consider various factors.

In this blog, we will introduce 8 key aspects to help you make an informed decision when purchasing solar street lights and ensure you get a reliable, durable, and high-quality solar street light product.

The Current Solar Light Major Issues in the Market

Before we start to talk about the facts that affect the solar street light quality, let's take a look at the two major issues currently existing in the solar street light market:

Overrated LED Lamp Power:

If you have visited wholesale markets or online platform, such as amazon, you may have noticed that the street lights being sold are labeled as 100W, 200W, 300W, or even 1000W. However, when installed, the brightness of these lights is very poor, making you wonder if these power ratings are accurate. The answer is obviously NO.

Overrated Battery Capacity:

The issue of overrated battery capacity is also very common. If you buy solar street lights at very cheap prices, you may find that the stated battery capacity in the specifications is quite large. However, after testing, the lighting time is very short, or the brightness of the light diminishes significantly after a few hours, and it may not even provide adequate illumination throughout the night. This is likely due to the use of batteries with false or poor quality capacity, which cannot store enough energy for sustained lighting.

If you encounter these two problems, please read the following content carefully as it will greatly assist your procurement of solar street lights with satisfactory quality for your project.

8 Things To Know Before Buying

Solar Panels

As we all know, solar street lights generate power through solar panels. Do you know the types of solar panels available and their differences in conversion efficiency?

Monocrystalline Solar Panels:

Monocrystalline solar panels use single-crystal silicon cell, offering high conversion efficiency, up to 23%. However, they are more costly but have excellent performance under strong sunlight. They also have a smaller size for the same power output, making them more resistant to wind and other environmental factors.

Polycrystalline Solar Panels:

Polycrystalline solar panels are manufactured with a simpler process, resulting in lower costs, but their conversion efficiency is slightly lower than monocrystalline panels, ranging from 18% to 20%. They perform well in overcast and rainy conditions. For the same power output, they have a larger size compared with mono solar panel.

Amorphous Solar Panels:

Amorphous solar panels have lower conversion efficiency and larger size, making them less popular and rarely used in solar street lights.

You may wonder if polycrystalline solar panels, with their better performance in overcast conditions and lower costs, should be preferred. However, we need to consider the average weather data throughout the whole year and the wind resistance level.

For road and municipal engineering projects, we recommend using monocrystalline solar panels due to their smaller size, equivalent power generation, and higher wind resistance.

For wholesale and retail markets with lower power solar lights, polycrystalline solar panels can be a cost-effective choice.

LED Luminous Efficiency

Currently, the most commonly used brands for solar street lights in engineering projects are Philips, Bridgelux, OSRAM, and CREE. The lamp beads' models are 3030 and 5050, offering higher luminous efficiency of up to 240LM/W, making them more energy-efficient. Their lifespan can reach 70,000-100,000 hours, but they come with higher prices.

For wholesale and retail markets, Chinese-made 5730 LED chips are commonly used, with a lifespan of 30,000 to 50,000 hours and a luminous efficiency of 120lm/W, offering more affordable options.

If you are purchasing solar street lights for a road engineering project, high luminous efficiency LED chips with long lifespans are your preferred choice.

Lamp Color Temperature

The color temperature of solar street lights is another important consideration as different installation environments may have specific requirements. For example, for solar street lights installed in residential communities, consideration must be given to the impact of color temperature on wildlife. High color temperatures can seriously affect the sleep of small animals and disturb human sleep patterns.

In areas with poor air quality or heavy fog, color temperature must consider its penetrative ability to enhance driving safety.

You can refer to this article for more knowledge about color temperature.

LED Lamp Color Temperature Selection Guide

LED Lamp Power

As mentioned earlier, the market currently offers solar street lights labeled as 100W, 200W, 300W, or even 1000W. We often receive inquiries about why our solar street lights do not have 200W or 300W options. However, the actual brightness is very low.

In reality, these power ratings are exaggerated and mostly targeted at the low-end market to cater to consumers' preference for higher power lights.

If you have a basic understanding of physics, you can easily calculate that, for example, a 200W street light consuming power for 10 hours would be 200W × 10H = 2000WH. If the street light uses a 3.2V 45AH battery, the energy it can store would be 3.2V × 45H = 144WH, which is insufficient to meet the actual lighting requirements for a 200W luminaire.

Therefore, we generally recommend focusing on lumens, not power, when choosing solar street lights for engineering projects.

You can refer to another blog of ours for a better understanding of the difference between Lumens and Watts.

Wattage vs Lumens: Better Understanding Lamp Brightness

Battery System and Safety

Solar street lights previously used lead-acid or gel batteries, which had large capacity but low discharge depth, large size, and heavy weight, making them susceptible to theft, and they have gradually been phased out of the market. Nowadays, lithium batteries are commonly used, but due to fierce market competition, various types of batteries have emerged. The more common types include 3.2V, 11.1V, 12.6V, 12.8V, 25.6V, etc.

3.2V System

3.2V Solar Street Lights use multiple 3.2V lithium iron phosphate batteries connected in parallel and are generally used for small power (less than 30W) solar street lights for the civilian wholesale market. This system is stable, and through our engineers' continuous efforts, 3.2V solar street light systems have achieved a breakthrough of up to 40W, significantly reducing costs. However, there are now many second-hand batteries in the market, requiring careful selection.

11.1V System

11.1V lithium batteries are ordinary ternary lithium batteries. These batteries have high energy density, small size, and are cost-effective. However, they have poor high-temperature resistance and are prone to fires, but they perform well in low-temperature conditions.

12.6V System

12.6V solar street lights are, in fact, 11.1V batteries, as the charge termination voltage for 11.1V lithium batteries is 12.6V. Some manufacturers use this as a misleading marketing tactic to give the impression of higher battery capacity.

12.8V System

12.8V Solar Street Lights use multiple 3.2V lithium iron phosphate batteries connected in series and parallel to achieve the desired capacity. These lights require high-quality batteries to ensure performance and stability.

25.6V System

25.6V Solar Street Lights are designed for high-power LED street lights, using higher voltage to reduce charging and discharging current, making the system safer.

In summary, ternary lithium batteries have a higher risk of high-temperature incidents but perform well in low-temperature conditions, while lithium iron phosphate batteries have excellent high-temperature performance and are stable and safe.

Therefore, we generally recommend using 12.8V lithium iron phosphate batteries for your solar street light projects to ensure quality assurance.

Lamp Working Hours

Due to cost and installation size constraints, solar street lights are currently unable to achieve the same brightness and lighting time as grid-powered street lights. Therefore, solar street lights typically use a time-segmented dimming mode, automatically reducing the brightness to a lower level during hours when no one is passing by during midnight, which helps to save energy and reduce the battery capacity and solar panel's required power.

For example, for solar lighting in basketball courts, athletes usually finish their activities before 10 pm. Therefore, the lighting time is generally set for 6 hours.

If you have specific lighting requirements, it's essential to communicate with your supplier promptly to ensure that the solar street lights meet your project's needs.

Lamp Pole

The quality of the lamp pole also significantly affects the solar street light's lifespan. Using substandard lamp poles can lead to rusting, breakage, and other risks.

Currently, the mainstream lamp poles use galvanized or hot-dip galvanized materials.

Galvanized Pole:

It is cheaper and easier to manufacture, but if the welding points are not adequately treated against rust, it can easily rust.

Hot-Dip Galvanized Pole:

It is more expensive, requires a more complex process, and has multiple procedures to prevent rust and corrosion, making it more suitable for government projects.

Warranty

Warranty is also crucial because solar street lights are electronic products and may experience malfunctions. No Solar Street Light manufacturer can guarantee that their solar street lights will never experience any faults during their usage.

Currently, some solar street light manufacturers offer 10-year warranties to secure orders. However, it is challenging to believe in a 10-year warranty.

Therefore, a typical quality-assured solar street light comes with a 3-year warranty, and some may offer up to 5 years, but it is essential not to fall for exaggerated 10-year warranties.

Conclusion

When purchasing solar street lights for your project, do not merely focus on the price and appearance. Instead, prioritize the products' performance and quality. Engineering projects require solar systems that are reliable, stable, and durable.

Through the 8 key aspects introduced in this blog, we believe you now have a deeper understanding of how to select the most suitable solar street lights for your needs. When making a purchase, we recommend considering all relevant factors and choosing reputable and service-oriented manufacturers to ensure the solar systems' reliability and long-term usability.

We hope this blog has been helpful to you and wish you success in finding satisfactory solar street light products to contribute to the green lighting cause!

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