Usually, we always receive several questions about designing solar street lights from our clients. These include the application site, pole height, and dimming method. The illumination simulation is also a common thing to ask, particularly for those clients that do large-scale projects. As a solar street light factory with 10 years of production experience, we always seek to answer these questions profoundly.
This solar street light proposal has won over 100 government projects in the United States, Spain, Australia, Dubai, Philippines, Malaysia, and other countries.
Important Factors to Consider Before Designing Solar Street Lights
Application
You can use solar street lights in many applications, such as main roads, highways, community roads, remote areas, parks, parking lots, etc. Of these applications, most consumers usually use solar-powered street lights on small-scale roads, while some are on main roads. Street lights are commonly seen on highways as these areas require very stable street lighting. Usually, expressways have the highest requirements for luminosity and lighting time, followed by main roads and small-scale roads with little traffic.
However, solar street light is not a one-size fit to all lighting solution. Each application site, LED power, solar panel power, battery capacity, and dimming method are designed differently. Therefore, the installation site is the primary factor consumers should consider when creating solar streetlights.
Not all places are suitable for installing solar street lights. For example, areas with a lot of shade, insufficient light time, and low temperatures (Canada, Russia, etc.) are not ideal for solar lights. Solar panels may generate less power in locations with a lot of shade and little sunlight. On the other hand, places with low temperatures can reduce the battery’s charge-to-discharge ratio. Therefore, when customers ask about solar street light solutions, it is necessary to know the installation site of solar street lights.
Pole Height and Distance
The solar street light pole’s height and distance are crucial factors when designing solar street lights. We typically model a range of LED power according to the pole height, its application site, and our customer requirements.
Usually, the height of the street light pole ranges from 6 meters to 12 meters. The small street light pole is between 6 meters and 8 meters. The height of light poles on main roads and highways is usually between 8 and 12 meters. Meanwhile, the spacing or distance of the street lights pole will determine the lenses needed to make the road lighting uniform.
Brightness and Dimming Way
On the other hand, the dimming method will determine the design of the solar panel power and its battery size. Usually, there are three dimming methods: full brightness all night, time-controlled dimming, and induction dimming (motion dimming). The energy consumption of the three dimming methods is from high to low. Correspondingly, the solar panel power and battery size are set from large to small.
Dialux Simulation
DIALux is the most beneficial lighting design calculation software that street light designers use on the market today. This software can efficiently meet all lighting design and calculation requirements. Generally, professional designers utilize it to solve all problems: from standardized indoor, outdoor, or street lighting calculations to vivid visual stereoscopic.
On the other hand, the IES light distribution curve file refers to the distribution of light intensity from light sources (or lamps) in all directions in space. But since its extension is “*.ies,” we usually call it the IES file directly. If the IES data corresponds to the actual production lamps, the simulation can genuinely reflect its brightness after you install them.
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Friendly Reminders When Designing Solar Street Lights
We have listed some of the few reminders that you should take note of to avoid getting the worst solar street light installation. Just pay attention to these:
Prevent Spurious Parameters
While doing solar lighting solutions, sometimes we encounter instances where the customer’s target price is lower than the material cost. We often find many unreasonable designs while checking the customer’s parameter requirements. For example, the height of the street light pole is 6 meters, and the power of the street light is required to reach 100W. However, the power of the 100W LED is only 60W or 80W for the solar panel.
Yes, that’s a parameter that some solar street light competitors deliberately flagged as falsely high. That’s why some design costs are higher than the actual customer wants. We need to decipher industry secrets for you to explain them well to your clients.
（Click here to check our solar street lights specs. )
Fake LED Power and Lumen Values
Most of the time, the human eye’s brightness perception is inaccurate. Compared with a dark road, a 5-10-watt street light mounted on a 6-meter pole can see the road. The actual 5-watt to 10-watt light will be labeled 100W or 200W. But, the naked eye cannot accurately distinguish the specific brightness of the lights. Therefore, if you only compare the surface parameters, it will be difficult to see which scheme is the best.
A simple way to detect brightness is to measure the LUX value of the road surface. All you need is a small light meter to measure it.
Fake Battery Capacity
Fake battery capacity is typical among some manufacturers. To give some ideas to prevent getting the fake one, check its battery voltage, battery AH, and battery life. Manufacturers mostly fabricate these battery parameters, so you should be vigilant.
Most solar street lights use battery voltage between 3V and 12V. Between the two, the 3V voltage battery costs are lower than the 12V battery voltage. Usually, cheap small lights use second-hand 3V voltage batteries. However, if it is a second-hand battery, its cycle life will not last long.
Many manufacturers also fake-marked the AH of batteries. The only way to determine if they are fake is to disassemble the solar street light. By then, you can test the size and quality of its battery pack.
Strictly speaking, the life of a battery corresponds to the number of cycles. So, the battery capacity will gradually decrease by increasing the charging and discharging times. If it is a grade A quality lithium iron phosphate battery, the number of cycles can be more than 1500 times. If the battery capacity is large enough, you can use the solar street light for over five years.
Many manufacturers use low-capacity batteries, even poor-grade batteries, and second-hand batteries to meet the customers’ requirements for low prices. Thus, many low-quality solar street lights have a lifespan of only one or two years or even a few months.
Fake Solar Panel Power
Since the power and size of a solar panel are directly proportional, the power of a solar panel is rarely spurious. In other words, its power will not be overstated too much. But you need to pay attention to the quality of the solar panel. Poor-quality solar panels have a lifespan of only 1 to 2 years or even a few months.
Four Key Points for Designing Solar Street Lights
- The solar panel is the most essential component to prolong the lighting time, followed by the solar battery. The energy stored will still be used up if the solar panel’s power is not large enough and its battery capacity is too large. If the battery capacity is just enough and the solar panel is powerful, it can generate enough electricity even on rainy days. The last reason is that solar panels are much cheaper than batteries. The life of solar panels can reach 25 years, while the life of batteries is only about five years.
- The solar street light system is partially charged as long as it is not very dark. Based on our experiment, on a cloudy day with 25 degrees Celsius temperature, the 60W solar panel and MPPT obtain 15W charging power.
- The importance of smart lighting. Some guests want their solar street lights to be bright all night and do not like induction and time-controlled dimming. But smart lighting means saving energy effectively and saving energy means saving money in your pocket.
- You should also check the brightness of the solar streetlights. Solar lamps with 2 – 50 lumens are suitable for decorative purposes, whereas lights with 50 – 200 lumens are ideal for security.
ADN now concludes that high-efficiency LEDs can effectively reduce the cost of solar street lights. Below we have listed a 150lm/w LED and 200lm/w LED solar street light cost comparison table.
| 150lm/w solar street lamps | 200lm/w solar street lamps | |
| Lumens | 3000lm | 3000lm |
| Led Power | 20w （$5） | 15w （$8） |
| Solar Panel Power | 40w （ $16) | 30w ($12) |
| Battery | 160WH ($30) | 120WH($22) |
| Aluminum house | $20 | $16 |
| Others | $10 | $10 |
| Total Cost | $81 | $68 |
We, therefore, conclude that the higher the power of the solar street light, the greater the cost savings with high-efficiency LEDs.
Solar Street Light Design Formula
In solar street light design, solar panel power and battery capacity are mainly designed according to the power of the LED. Due to different application scenarios, the requirements for the solar lamp lighting time and the induction mode vary.
Below are the three different solar street lights design formulas that we derived from our professional experiences:
30% Motion Dim / 2-3 Hours Full Brightness, 30% Motion Dim in Left Hours
Solar Panel Power (w）= 1.5 – 2 x led Power (w)
Lithium Battery (WH)：8 – 10 x Led Power (w)
Take 30W led power, for example. Solar panel power needs 45W to 60W, while lithium battery needs 240WH to 300WH.
6 Hours Full Brightness，40% Brightness in Left Hours
Solar Panel Power (w）= 2 – 2.5 x led Power (w)
Lithium Battery (WH)：13 – 16 x Led Power (w)
Take 30W led power, for example. Solar panel power needs 60W to 75W, while lithium battery needs 390WH to 480WH.
Full Brightness Whole Night
Solar Panel Power (w）= 3 – 4 x led Power (w)
Lithium Battery (WH)：16 – 20 x Led Power (w)
Take 30W led power, for example. Solar panel power needs 90W to 120W, whereas lithium battery needs 480WH to 600WH.
Generally, there will be multiple intervals between each Led power because the lighting conditions of each place are different. Solar installers can use this formula for government projects with high-quality requirements and need sufficient light time. However, we recommend configuring higher-power solar panels in areas with altitudes above 30°.
Practical Engineering Case
Now let us introduce a solar street light project in Australia for you to understand what we said above fully.
Requirements:
- LEDlumens above 4000lm
- 3000K CCT
- Pole Height: 6M
- Full Brightness the whole night
Our Solar Street Lights Proposal
- Bridgelux 5050 Led Chip in 3000K
- Whole Solar lights can reach 180-190lm/w
- LED Power: 22W
- Full Brightness all the time
- 90W Solar panel
- 12.8V 42AH Lifepo4 lithium battery
Our configuration usually illuminated the entire solar street light system for a week, even during the rainy season. Our proposal samples also managed to win hundreds of trial orders. Based on our records, our solar street lights are still working normally today, even after two years of installation.
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