As the quality of LED chips continues to improve, the LED power supply becomes the main component that restricts LED street lamps’ quality and lifespan. In terms of cost, a good quality LED power supply accounts for about 25% of the total cost of LED streetlights. Therefore, ADNLITE published this article about LED street light power drivers to give you more ideas about this matter.
Main Parameters of Street Lamp Power Supply
When choosing a street light power supply, it’s crucial to understand first the following key parameters. To be closer to the actual situation, let’s take a 100W street lamp power supply from Philips as an example.
Input Current Range
The power supply is connected to the input current on the side of the grid. Based on the image, the input current of this power supply is 0.48A.
Typically, the input voltage on the side of the power supply is connected to the grid. It is also divided into wide input voltage and narrow input voltage. The image provided here shows a 220 to 240VAC, which belongs to the narrow input voltage. Generally, the usual number for wide input voltage ranges from 100 to 305 AC.
It’s also to note that the grid voltage is unstable. However, the wide input voltage can ensure the safe and stable operation of the LED chip. There is also an input voltage range of 249 to 528VAC, which is commonly used for 380V industrial power usage scenarios.
Max Input Power
The maximum input power of the power supply shown in the figure is 110W. The maximum input power of this power supply is the street lamp power. We recommend setting the actual power to at least 10% lower than the maximum input power of the power supply. In this way, users can ensure the stability of the street lamp power supply for a long time.
Generally, the power supply is connected to the LED side’s voltage. Based on the image presented, the output voltage range of the power supply is 46 to 143V. Always make sure the connected PCB voltage is within the range of the power supply’s output voltage.
The power supply is connected to the current on the LED side. The figure presents that the power supply’s output current range is 0.3 to 1.05A. You must note that the connected PCB current is within the range of the output current of the power supply.
The output power range of the power supply in the picture is 50-100W.
Output Current Tolerance
You must also note that the constant current precision output by the LED power supply plays a vital role in the LED street light’s lifespan.
The energy conversion efficiency of the power supply shown in the figure is 90%. That is to say, if the input power is 100W, the power of the LED chip is 90W.
In the given figure, the output current range is greater than 98%.
But do you know what is the power factor of a power supply? If not yet, allow us to discuss it for you. The power factor is a factor that measures the efficiency of electrical equipment. The low power factor indicates that the circuit uses a large reactive power for the conversion of the alternating magnetic field, which increases the power loss of the line. Therefore, the power supply department has certain standard requirements for the power factor of the power consumption unit.
In an AC circuit, the cosine of the phase difference (Φ) between the voltage and current is called the power factor and is represented by the symbol cosΦ. Numerically, the power factor is the ratio of active power to apparent power, that is, cosΦ=P/S.
Generally, the maximum lightning protection level of a street lamp power supply is 4kv. If a higher lightning protection level is required, such as 10KV, and 20KV, additional lightning protection components are required.
The IP rating refers to the rating of the electrical equipment enclosure against the intrusion of external foreign objects. The IP rating of all street light power supplies is usually IP67. The IP67 rating means the power supply can work underwater for a while.
To read the IP rate, we will give you an idea, particularly about the numbers. Basically, the IP rating consists of two numbers. The first number means dustproof, while the second number means waterproof. Also, note that the larger the number, the better its protection level.
Generally, the average operating temperature ranges from -40 ℃ to 80 ℃. This range applies to most areas on Earth.
This feature is generally optional for LED Street lights. Typically, there are 3 to 5 time periods of dimming. Sometimes the power supply with a dimming function is about 10% more expensive than the ordinary power supply.
Usually, many roads have few pedestrians in the second half of the night. So during this time, we can set the street light power to only 50% of its full power. In this way, the time-controlled dimming function can effectively save the energy consumption of the LED street lamp.
Output Lumen Compensation (OLC)
As the lighting time increases, the light efficiency of the LED will gradually decrease. So over time, the power supply can increase the output current a little bit to increase the LED power. This OLC function can offset the reduction in lumen value caused by LED light efficiency attenuation.
Common dimming methods are 0-10V and DALI ( Digital Addressable Lighting Interface – Wikipedia ).
D41 is an expansion of DALI-2, and devices made using DALI-2 with new specifications and features, such as Zhaga pockets, are considered D4i products. DALI-2 items that fulfill the requirements of auxiliary power, diagnostics, and electricity metering are eligible for D4i certifications.
Auxiliary Power Supply
If you need to connect additional sensors, cameras, etc., the auxiliary power supply function can support an additional set of outputs.
Street Light Power Driver Brand
The power driver quality of the Meanwell, Inventronics, Philipps, Sosen, Osram, UE, MOSO, and LIFUD brands is outstanding. But, the common power supplies we use are Meanwell, Philipps, and Sosen. Let’s make a simple comparison here to give you an idea of what brand suits your requirements better.
Meanwell VS Philipps VS Sosen Power driver
Price: MeanWell > Philipps > Sosen
Quality Stability: Meanwell > > Philipps > Sosen
The price of the Meanwell power supply is about 20% higher than that of the Sosen power supply. However, the quality stability of the three brands of power supplies will not be much different.
7 Tips on How to Choose a Street Light Power Supply
- All LED streetlights use a constant current power supply.
- It is the circuit design and the quality of electronic components that determine the quality of the power supply. The main electronic components are capacitors, inductors, MOS, and so on.
- The input voltage and current of the PCB board should be consistent with the output voltage and current of the power supply.
For example, the power of this street light is 100W, meaning the input power of the street light power supply is 100W. The power supply efficiency is 90%, then the output power is 100W x 90% = 90W. The output voltage range of the power supply is 46V to 143V. Then, its output current is 0.3-1.05A.
If we choose the Philips 5050LED chip here’s the calculation. The common input voltages of the Philips 5050 chip are 3V, 6V, 24V, and 30V. But, we will choose 24V here.
90 5050 chips, 5 LED chips in a series, 18 in series, and parallel. In this case, the input voltage of the PCB is 24V X 5 = 120V. The PCB current = 90W / 120V = 0.75A. In this way, the voltage and current of the PCB are consistent with the power supply.
- At least 10% of the actual load power of the power supply is reserved. For example, if the maximum power marked by the power supply is 100W, the LED street light’s power should only be set to 90W. This can greatly increase the service life and reliability of the power supply. Note that the shorter the actual service life of the power supply, the higher the maintenance cost of the street light.
- If it is a power supply with a 2-year warranty, it is very popular to use a 50W power supply to stack 100W, 150W, and 200W. This cost is lower, and it can also reduce the replacement cost after the power supply is damaged.
- All street light power supplies need to be isolated power supplies. The isolated power supply can be divided into primary isolation power supply and secondary isolation power supply.
The Class I isolated power supply not only contains the most basic anti-shock protection functions but also needs to have a grounding function.
In comparison, the Class II isolation power supply is safer than the Class I isolation power supply. It also has double isolation or reinforced isolation. More so, all street light power supplies are preferably secondary isolated power supplies.
7. The lower the output current of the power supply, the higher the cost and the higher the energy efficiency conversion rate.