Kizashi Club

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Individuals may post anything, but it would be best to keep it related to automobiles.
 #47594  by KuroNekko
 Sat Aug 18, 2018 10:01 am
iam jellywin wrote:I have heard everything great about LED lights until now, be it for the indoor use or outdoor. But, would really be interested in knowing if there are certain demerits to LED lights.


http://bit.ly/2A646lJ


I avoided responding to this thread because the post looks like spam, but for discussion's sake, why not? I like lights.

In my opinion, LEDs are mostly superior to other forms of lighting in automotive and other applications, but there are demerits.
In terms of automotive applications, the main one is heat. LEDs are typically heat resistant to some degree, but can't get too hot or it will drastically reduce the reliability and longevity of the emitter, the part actually producing the light. This is why high performance flashlights and headlight bulb kits focus so much on cooling. From cooling fins to timed or temperature-based power step-downs, these features are almost always found on high performance LED products like powerful high-end flashlights. For car bulbs, you will often find LEDs attached to heat sinks and/or fans. Aftermarket LED kits often come with fans at the base of the LED bulb. The purpose is to obviously cool the emitter down from getting to a temperature that can compromise the emitter.

Meanwhile, other bulbs used in automotive applications aren't as susceptible to heat issues. For halogen bulbs, the filament is in halogen gas to even boost the temperature and performance of the filament's glow to produce light. Filament bulbs are also effective as heat sources hence they are used in heat lamps for things like keeping food warm or heating up terrariums for reptiles.

HIDs are also popular in vehicles for lighting. Again, these aren't as susceptible to heat issues because they literally work by creating plasma as the light source. The ballast creates an initial high voltage to melt the halide salt to plasma, after which a lower voltage maintains the light. This is why after initial ignition, HID systems often run on 35 watts vs. the 55 watts comparable halogen bulbs utilize. HID bulbs typically don't require a cooling apparatus unless overdriven. However, a comparative LED bulb does require cooling and the need for heat sinks and fans makes them bulkier and harder to install, especially as an aftermarket upgrade or retrofit.
The heat issue is also why some people prefer HIDs for low beams for sustained light output. The belief is that HIDs fare better for emitting light hours on end and don't have the weakness to heat that LED bulbs do. However, LEDs are better for high beams due to the instantaneous full-power (unlike HIDs that require warm-up) and that most high beams are used only sporadically.

All this being said, many new cars have factory installed LED bulbs for all sorts of uses, including headlights. Advances in emitters and bulbs specifically designed for automotive use has made them suitable for OE applications. Even some economy cars like the Toyota Corolla now come with LED low beams standard.

Another complaint with LEDs is the color temperature or the "bright white light" of LEDs. It's often referred to as tint. I've even read articles about how LEDs used in homes and street lights are detrimentally affecting the sleep cycle of people by being too bright and mimicking daylight from the sun even at night. While interesting, it's really not an issue with LEDs themselves but the color temperature that's utilized in that application. After all, LEDs are offered in a huge spectrum of colors. Many bulbs and lamps even have not only the capability to increase or decrease brightness but literally change their Kelvin color temperature (tint) or base color all together. For example, I have a camping lantern that I got for under $20 that can not only variably change brightness from 3 to 350 lumens but also change Kelvin color temperature (tint) from 2700K (warm white like halogen) to 6500K (cool blueish white). It can also be a dim red light. Hence, it's my opinion that LEDs aren't the problem but it's more what color temperature and lumen output people are using them in.

All that being said, LEDs can be incredibly bright and powerful while being very power-efficient. If properly thermally managed, emitters can last tens of thousands of hours compared to the hundreds of hours of a halogen bulb or the thousands of hours of an HID bulb. The pros heavily outweigh the cons hence, they have come to revolutionize and replace older and less efficient forms of lighting in many applications, including in automobiles.