A Light Emitting Diode, or LED, is an essential component in solar and LED lamps that convert electrical energy into visible light. So, it is important that if you were to choose good quality LED chips, certain standards must be considered. It is because a good selection of LED chips can greatly reduce the cost of solar lamps while ensuring the high brightness of solar lamps.
Here, we will describe in detail the number of LEDs for solar lights. Then, explain the easiest method for testing and comparing the brightness of solar lights.
LED Main Parameters
Now, let’s take a closer look at the main parameters of the LED chip. After carefully reviewing it, I think you’ll understand solar lighting products better.
Luminous efficiency refers to the amount of luminous flux (Lumens) emitted by an LED lamp per watt of power (watt). So, the unit of light efficiency is lumens per watt. LED light efficiency and LED power together determine the brightness of the LED light. This is important, and ADN will reiterate it later in the article.
The LED chip and overall light effects are other things to consider. The LED chip needs to be soldered to the PCB board and then covered by the lens (some lamps have a reflector and a glass cover). Therefore, parts of the light emitted by the LED will be blocked by the lens, about 10% to 20% (depending on the quality of the lens – the light transmittance). Some suppliers sometimes only label the LED chip’s theoretical maximum luminous efficacy value. So, when purchasing lamps, you need to confirm whether the LED light effect or the whole light effect is on the parameter table.
LED Chip Brand
Some of the popular manufacturers of LED chip brands are Philipps, CREE, Bridgelux, Samsung, Epistar, Sanan, and so on. The chip brand has nothing to do with chip quality. But, massive listed companies can still supply LED chips which is a great advantage for them.
The light decay of most brand chips has been done very well. What determines the quality of the chip is the luminous efficiency level under a certain LED chip model. We will briefly explain several LED chip models in the following section.
LED Chip Model
A specific LED chip model has its determined power, voltage, current range, and maximum luminous efficacy. In addition, different packaging factories and different light efficiency grades can have different prices and light effects for the same type of chip under one brand.
For example, the 3030 chip. The same Philips 3030 chip can be packed from the original Philips Luminous package factory or other LED chip package manufacturers. In this case, the 3030 LED Chip luminous efficacy can vary from 120lm/w to 190lm/w. As a result, prices will also vary widely.
COB is a Chip-on-Board, which is used to adhere the bare chip to the interconnect substrate with conductive or non-conductive glue and then wire bond to achieve its electrical connection. COB LED is also called COB LED source or COB LED module. These are available in strip/square/round packages. COB light sources are mainly used in downlights and ceiling lamps, and the maximum wattage of a single piece is not more than 50W. It is undeniably in demand since ADN has encountered a lot of customers who prefer COB light sources used in solar street lights.
CMD LED refers to the packaging of a single LED chip. Regular models include the following:
- 3528 SMD LED Chip, power 0.06w, lumen value 6-7LM, 7-8LM, 8-9LM, the maximum luminous efficiency can reach 160LM/w.
- 2835 SMD LED Chip, power 0.2w, lumen value 20-22LM, 22-24LM, 24-26LM, the maximum luminous efficiency can reach 130LM/w.
- High-power 3030 LED Chip, power 1w, lumen value 120-160LM, the maximum luminous efficiency can reach 190LM/w
- High-power 5050 LED Chip, power 5w, lumen value 800-1100LM, luminous efficiency up to 230LM/w
The 3528 chips are usually used in retail low-power solar lights, so that you can see many LED chips densely packed on these lights. However, most of the 3030 chips are used in high-power solar streetlights. ADN recommends using the 5050 chip and adjusting it directly to the highest light efficiency of 230 lm/w so that the total amount of light produced can reach about 190-200 lm/w.
Numbers of LED chips
If you have carefully read the explanation of our light effect and chip model parts, you will know that the number of LED chips is not directly related to the LED power. But we also have a supplementary note: the power can be adjusted within a range for a single LED chip. The higher the power, the lower the luminous efficacy. For example, the maximum capacity of the Philips 5050 chip is 5W, the light efficiency at 5W is 170lm/w, and the light efficiency at 0.8W can reach an astonishing 220-230lm/w.
Color temperature can be understood as the color of light. The normal color temperature of the LED is between 3000K and 6000K. Below 3000k is yellow light; above 6000k, the light turns blue. Under the same LED chip and power, the higher the color temperature, the higher the light efficiency. So, if the customer has no special requirements, the color temperature of the solar lamp generally falls to the normal color temperature ranging to 6000K.
Color Rendering Index
The color rendering index is the light’s ability to restore the object’s original color. The color rendering index of sunlight is 100, the incandescent lamp is also 100, the energy-saving lamp is 80-90, and the LED is 70-90. Under the same LED chip and power, the higher the color rendering index, the lower the light efficiency. The color rendering index of outdoor lighting is generally 70-75.
The input voltage of a single LED chip is generally 3V/6V, and the current is also tiny. In addition, LEDs generate a lot of heat when they are working. Note that working at a high temperature for a long time will greatly reduce the life of the LED. So, the LED chip needs to be soldered to the PCB. The PCB can effectively dissipate heat when the LED is working and ensures the normal voltage and current input of a single LED chip.
Moreover, the LED PCB must be covered with an acrylic lens after the LED chip is soldered. In designing the PCB, it is not only necessary to consider the arrangement of the lens for each LED but also to ensure the current and voltage of the input and output. This will guarantee the efficiency and safe operation of the LED.
There are two types of lens materials: acrylic and glass. The transmittance of high-quality glass and acrylic can reach more than 90%. However, acrylic tends to deform and turn yellow over time.
Another thing, the lens can redistribute the light emitted by the LED. For example, there is a bat wing-shaped light distribution lens for road lighting, and there can also be a light distribution at different angles of floodlights (30°/60°/90°/120°).
Misunderstandings about LED Chips when Buying LED Lamps
Both sellers on online marketplaces like Amazon and lighting manufacturers in physical stores have made a lot of inaccurate claims about the brightness of LED lights. These are the following samples:
- The greater the number of LED chips, the brighter.
The number of LEDs does not determine the LED light’s brightness or the LED light’s power.
- The higher the power, the brighter.
LED power is an important parameter that determines the brightness of LED lights, but it is not the parameter that directly measures the brightness of LED lights. The lumen value is the parameter used to measure the brightness of the LED light.
You can better understand the relationship between lumen and power by using the following formula:
Lumen value （lm） = power（w) x luminous efficacy (lm/w)
Therefore, the parameters that determine the brightness of LED lights are LED power and light efficiency. Under constant lumen value, the higher the luminous efficiency, the lower the power. As a result, a lower cost of the overall solar lamp will be achieved.
- False mark parameter
To avoid such deception, the solution is to light up the solar lamps at night and measure the illuminance of the lamp with a LUX meter. Below is a photo of the light meter, which is about the size of a TV remote control.
A few Notes About the LED Power of Solar Lamps
- The market power is the maximum operating power of solar light. Frequently, the power of solar lights is unstable.
- The solar light system will reduce the LED power to effectively conserve battery power when no one is near the solar light.
- The solar light system will also automatically turn down the LED power when the battery’s stored power drops to a certain percentage. When the battery energy drops, the LED power of the 3V voltage solar lamp will drop faster than the 12V voltage solar lamp LED power.