Views:3247 Author:Site Editor Publish Time: 2017-01-25 Origin:Site
In this post, we will introduce to you the methods to select the best led headlights with fan or without fan from the engineer view, by analyzing what is important to a led headlight bulb, telling the methods to test the led headlight and get a conclusion from the data. And also mentioned what other factors are related to the quality of led headlight bulbs. After reading our post and follow our steps, you will be able to easily judge a led headlight is good or bad.
Three Type of Led Headlight Heat Sink – Aluminum heat sink, fan for heat sink and copper braid heat sink, what are the different among them? The pros and cons?
What Should We Concern on When Picking Fanless Led Headlight Bulbs? – Led Chips, bulb size, or Lumen output? All these info are told by the seller, but what should we concern on when picking fanless led headlight bulb?
How to Find a Good Fanless Led Headlight? – Three steps to test your new led headlight bulb, you will get the conclusion to this product.
How to find a Good Led Headlight with Fan? – led headlight with fan has higher lumen output and smaller bulb size. But this kind of product has their weakness as well. How to make a choice?
Other Factors Related to the Quality of LED Headlight Bulbs – Except the features we mentioned above, what else will affect the quality of led headlight bulbs?
All-In-One LED Headlight vs. LED Headlight with an External Driver – All-In-One led headlight and led headlight with driver, which is better? Please allow me to explain to you.
Three Types of Led Headlight Heat Sink
Car headlights are one of the most important components, HID bulbs and halogen bulbs are used on most of vehicles on road. In recent years, led headlight is becoming another choice for us to upgrade the car headlight. There are so many different led headlights available on the market, how to find the best led headlights for your car, which is often confusing.
LED headlight bulb basically can be divided into three types according to cooling method.
Fanless led headlight with Aluminum heat sink.
The heat sink is made from alloy Aluminum, cooling by thermal radiation of Aluminum itself.
The cooling capacity is very stable.
The volume of heat sink determines the heat dissipation capacity.
Fanless led headlight with Copper Braid heat sink.
The copper braid heat sinks are made from red copper wire with tin coating on the surface. Aluminum finned heat sinks are made from 6063 alloy aluminum.
The copper braid and wings are adjustable. They are all flexible and convenient for installation although in tiny space.
– To install, we got to unfold the copper braid to maximized heat dissipation. And all wings cannot be squeezed together. Otherwise, the cooling performance will drop a lot.
– Bulb body and heat sink are connected by hydroforming process or fixed by screws. They are not 100% attached together, if there are only 50% surface attached, heat can only transfer from body to heat sink through 50% attached surface, just like the river narrows at the entrance and water flows slower, which will affect the efficiency of heat transfer.
LED Headlight with fan
It relies on the fan to cool down the LEDs and bulb body.
The cooling performance is the best compared the others above.
– The fan quality is the vital factor to decide the lifespan of led headlight. When the fan is broken, the light output of led headlight will reduce a lot so that it cannot continue to be used.
– Fan will produce noise.
What Should We Concern on When Picking Fanless Led Headlight Bulbs?
Generally, we should look over a fanless bulb by four features,
– Beam Pattern,Continuously
– Flux (Lumen) Output,
– The Working Temperature
– The Volume of Led Headlight Bulb
The beam pattern is related to the Optical design and will decide the led headlight is street legal or not.Beam pattern won’t be changed once the Optics design is confirmed and the product mould is made.
But, the other three features have an interesting relationship and will be interacted. Bigger volume, better heat dissipation. Temperature rises, flux (lumen) output decreases. You can imagine LED headlight as laptop, and flux (lumen) output = processor speed; LED working temperature = CPU working temperature; the volume of led headlight bulb = the volume of laptop.
You couldn’t have a 13 inch Ultrabook laptop having top gaming performance; just like you couldn’t have a tiny led headlight bulb having the brightest flux (lumen) output. 15.6 inches laptop could have best gaming performance but it is heavy and not convenient to carry it with you, while big size led headlight absolutely have high flux (lumen) output but sometimes it don’t fit your car.
So choices must be made.
If you want it brighter, we can supply more forward current to reach the maximum relative light output of LEDs. So the led headlight could reach the maximum light output. But at the same time, LEDs will produce more heat and temperature will rise.
That means, we need to solve the cooling problem if increasing the brightness of led headlight.
If you want a better heat dissipation, we will need to increase the volume of the heat sink
There are the other methods to increase the heat dissipation capacity.
How to Find a Good Fanless Led Headlight?
First, check the cooling performance capacity
It would be better if the working temperature of bulb body and heat sink could be closer. That means the heat transfer is good and high-efficient from LEDs to heat sink.
If the working temperature of bulb body and heat sink has big difference, it means the heat transfer from LEDs to heat sink is bad. Most of heat will still remain around LEDs and driver will decrease the forward current to LEDs for controlling the operating temperature and protecting the LEDs not from being over the Junction temperature. Then the flux (lumen) output will decrease a lot perhaps in 10 minutes after light-on.
We can check the working temperature of LED bulb by thermal imager. Here is the images of Blade led headlight.
(One thing should be mentioned that, whatever CSP led chips or Cree high power led chips, they all have a Junction Temperature(Tj). If LEDs keep working beyond the junction temperature, the lifespan will shorten a lot. For a longer lifespan as well as the safety, we need to keep the LEDs working under their Junction Temperature. To know the Junction Temperature (Tj) of a LED, you can download and check the data sheet of the LED chip from the LED manufacturer’s official website. Normally, the Junction Tmperature would be 155℃ – 160℃ if the LEDs are suitable for automotive application.)
Second, check the lumen output and beam pattern
The initial lumen value ≠ Ture Lumen Value. As working temperature goes up, the lumen output of LEDs will decrease. But their decrease levels are different. Here you should read the Lumen Test Report from supplier or test by yourself. A led headlight kit claimed 4000 lumen could be had 3500 lumen, 3000 lumen or 2500 lumen in 30 minutes after light-on.
Here is the flux (lm) data of Blade led headlight. (single led bulb in testing)
Third, check the light beam pattern
As we mentioned above, the beam pattern will decide if your led headlight bulb is street legal or not.A bad beam pattern will produce glare light and dazzle the oncoming traffic. For safety driving, we will suggest you to pick a led headlight with great Optical design and a standard beam pattern.
We can test the beam pattern in the garage. Here is the beam pattern of Blade led headlight. We test in 4 meters from the wall. And take the photo by SLR camera in setting ISO: 100, Shutter Speed: 10, Exposure: 10. Get the beam pattern image as below.
Through the above processes, we can almost judge whether a LED headlight is good or bad and select the best led headlights by yourself.