Re: Weisslicht LED Headlights?
Originally Posted by
KDW4Him
Well said, what did your research do in finding the lumens specification was a function of how much light is produced based upon the amount of energy used? It's not just the light emitted, it's an energy conversion factor.
If we start with candlepower then we are on the same playing field but if you start with lumens the conversion to candlepower is skewed because of the energy used factor. That is why the LED rates higher lumens but isn't as bright isn't it?
Why would a Google search of "led headlight candlepower" in the quotes reveal no results with the quotes? How many LED spec pages show true candlepower?
I disagree with "Twice as much Lumens in the same Headlight means twice as much Candlepower in the resulting beam." Since lumens is total light output it could mean the LED is brighter but is the focus correct to where a driver needs it? This would be like your laser example. The H7 might be lower lumens but higher candlepower than an LED and produce more light where needed, on the road way in front of the car. This is why I really wish candlepower was the standard spec. Lumens can be deceiving.
Lumen has nothing to do with the ratio of light produced based upon the amount of energy used, or lumen being an energy conversion factor. That would be luminous efficacy, lumen per watt. Relevant to determine whether light is emitted efficiently. We all know LED is highly efficient.
From Wikipedia:
Lumen is the SI derived unit of luminous flux, a measure of the total quantity of visible light emitted by a source.
Candela is the SI base unit of luminous intensity; that is, luminous power per unit solid angle emitted by a point light source in a particular direction.
There is a lot on youtube that explains it much better.
There is no energy factor involved here. Of course actual output depends on the voltage and current delivered to the LED.
Higher lumens just means more light. And if you are able to focus all the light in a particular direction, it will result in more light in that direction. The more light you can concentrate into a smaller angel, the intenser the resulting beam will be. The intensity of this beam is measured in candela, known as candlepower.
The specifications of a LED flashlight will always (have to) be in candela, because a flashlight has a reflector and a lens, to point the light in a particular direction. Here candela value is really a measurement of how far a flashlight will throw a beam. Pretty relevant.
The specifications of a bare light bulb (like the H7 discussed here) will never be in candela, because a light bulb emits its light all around. It needs a reflector and a lens to point the light source in a particular direction.
This is why a Google search of the exact phrase "led headlight candlepower" will reveal no results. “headlight candlepower” does, but only for sealed beams. For a headlight with H7 there cannot be a fixed candlepower value, because it will depend on the variable of the H7 bulb used.
The reflector is visually very well explained in the above parabola.
What we are interested in here is the intensity of the headlight beam.
H7 is an industry standard that prescribe the exact location/position of the light emitting source, to which manufacturers design their headlight. Design the reflector and lens of their headlight, to optimally focus the light in a beam to properly light the road ahead.
The first generation H7 LEDs had several LEDs all around, up and down, not in the focal point of the reflector.
The latest generation has two opposed LEDs in the H7 focal point, resulting in a tight beam with no glare.
The practical problem we face here, is that our Crossfire headlight housing was not designed to accommodate the larger back end of the LED lights.
The one shown in the beginning of this thread, with the flexible heat sink, is a good candidate for narrow spaces. But I doubt whether the additional Canbus component box, assuming it is needed for our Crossfire. A solution for this might be to take the wiring out of the headlight housing and use the H7 LED type as shown in the youtube clip above. Proper dust caps should be available.
Last edited by SuperD500; 11-22-2018 at 05:07 AM.