As one of the renewable energy, solar energy is becoming more and more popular. And solar street lights market grows rapidly in the past 10 years because of the cost of solar street lights components, such as panel and battery, lowed down a lot.
And Especially this year in 2019, the solar panel price drop down 20% around compared to the solar panel price in 2018. With the battery cost lowing down in the following years, we can make optimistic estimates that the market of solar public lighting will keep on grow rapidly in the following 5 years.
The following diagram is the word “solar street light” in google trends since 2004 all around the world. It shows the worldwide market request of the solar street lights rises 5 times around.
In the market, there are 3 main types of outlook design: Seperated (split) design solar street lights, Two in one solar street lights, All in one solar street lights (integrated solar street lights).
The outlook of solar street lights can be different, but the key to deciding the solar street lights are the four components: solar panel, battery, led, and solar charge controllers. And the solar panel and battery are the main two components that take the most part of solar street lights costs.
At present, the solar street lights price is still the key point to limit the solar street lights markets. So the cost of solar panel and battery is the key to make sure that the solar-powered street lights are really helping end customers save their cost in electric bills.
So how to earn money in solar street lights business? The first and most important thing is how to design it.
When customers such as construction companies, a solar energy company and led lights companies to make the solar-powered street lights proposal for the government solar lighting projects, they have no idea how to start. Here we list the 5 main factors that need to be considered when design solar street lights.
At present, the main place of solar street lights installation is still in rural areas and islands that the grid power still hard to reach.
The first investment of the grid power will be huge in that place. So the solar street lights solution has a total advantage in Flexible investment. Customers can try some samples or demo projects to test the real solar street lights quality first and add the quantities as their initial needs after the testing.
Another place that we do not advise to install the solar street lights is in a cold place. Because the solar panel and battery can not work well in cold winter.
To make sure enough lighting time, solar panel and battery need to be set very big and the cost of the whole solar street lights system will be high accordingly.
In summary, the circumstance for solar street lights needs to be not-low temperature, full of sunshine and lack of grid power.
Height and Distance
After we make sure the place is ok to install the solar street lights, the next step is to make sure the height and distance of the solar street lights installation. If it is the main street, normally the street lights pole is the 8m-9m height with 30-40 meters distance.
If it is a park, country road, and pathway, 4-6 m height posts are enough. If it is a high mast for the stadium, height needs to be 15-20m.
Brightness, Lighting Time
After the installation height of solar street lights is confirmed, we can set the led power accordingly. And we set the solar panel power and battery capacity according to the led power, lighting time and dimming way.
Normally, for the rural place that there is little person nearby in the night, we set motion dim to save the energy. When there is no person nearby, the solar street lights will be lighting in very low energy to save energy. When there are the persons nearby, the solar street lamps will work in full power.
If the place is the main street in which there is heavy traffic in the first 6 hours of the night, we need to set 6 hours in full brightness and 6 hours in 30% to 50% brightness. No doubt that the motion dimming way will cost less energy than the auto-time dimming way.
Therefore, we normally set 1.5 times bigger for auto-time dimming way solar lighting solution than the motion dimming way solar lighting solutions.
The Quality of the Material
It will be a long topic for solar street lights components. Here we just listed the most important parts. There are 2 main types of solar panels: monocrystalline solar panel and polycrystalline solar panel.
Because the monocrystalline has a better conversion rate and better performance in cloudy days, the monocrystalline solar panel is what we advise for solar street lighting. And real good solar panel life can be more than 25 years.
The main battery types for solar street lights are lithium battery and gel lead-acid battery. Compared to the gel lead-acid battery, the lithium battery has a much longer cycle life and supports deep discharge.
Somehow, there is a bad quality lithium battery in which the cycle of life can be much shorter. And the same battery brand, there is the grade A, B, C for different quality and cycle life battery cells. So check the battery quality carefully when you talk with your solar street lights suppliers.
To the solar charge controllers, there are also two types: MPPT and PWM. MPPT controllers are more expensive than the PWM. Somehow, the MPPT controllers perform much better than the PWM controllers.
We did a real test, the 60W mono solar panel with MPPT controller on a cloudy day, its real output power can be 15W around.
However, the 60W mono solar panel with the PWM controller on a cloudy day, its real output power is 6-7W only. But MPPT controllers are not proper for all the solar outdoor lights projects considering the cost.
Led is already the main light source because it is energy saving. Now in 2019, the highest luminous efficacy of led chips can reach 230lm/w around. And the luminous efficacy is really important for the solar street lights system.
Because the main cost of solar street lighting system is in solar panel and battery. If we use higher luminous efficacy led chips, we can use lower led power to reach the same lumens.
Then we can low down the solar panel power and battery capacity to low down the whole solar street lamps costs. So if we use 230 lm/w led chips to replace 160lm/w led chips, the solar street lights cost can low down 30% more.
Yes, it is also important for the solar street lights installation. If we do not deal with some solar street installation details carefully, the solar street lights will not work well.
The first important thing is to make sure there is no shadow on the solar panel even small shadow such as leaf and wire.
The sent thing is to make sure there is no other bright light source near the solar street lights because the solar street lights have the function of dark to dawn dim. If the circumstance is bright enough, the solar street lights system will turn the led off automatically in the night.