The geometric reflector of the hi-beams is tuned for a very small incandescent filament that emits all of its light in a 360 degree pattern from a very small surface area emitter. An LED, on the other hand, emits all of its light from 2 panels that emit at only about 270 degrees from a relative surface area that is about 2-3x larger than the filament of an equivalent incandescent bulb.
So, from emitter placement alone, we have an LED that is engaging entirely different parts of the reflector design, putting light where it doesn't belong. Additionally, entire portions of the reflector aren't being engaged at all, due to the 2 sided design of LED bulbs. So, the net effect is an apparent increase in brightness because suddenly there is LIGHT EVERYWHERE! Wow, these things are bright, and that must be better, right?
The 9011 is roughly a 2,350 lumen bulb, and I'll (arbitrarily) give an optimistic Chinese LED headlight 3,350 lumens to give it a clear 1,000 lumen advantage. The long lasting OEM 9005 are roughly 1,550 lumens for reference.
We have the 9011 that will engage the reflector at exactly the right angles, putting exactly the right light pattern for Hi-beams onto the road; a narrow focused cone of light. All of the 2,350 lumens are projected to precisely where they need to be.
We have the LED with 3,350 lumens, engaging the reflector at the wrong angles, scattering the light over entirely new areas of the road. It appears bright, because there is more light. But much of the light isn't where it's supposed to be. In effect, the reflector is scavenging less light from the designed emitter geometry. If you trimmed the LED emitter size to be the same as the incandescent coil, lumens would be far less than the extremely condensed 9011 incan coil area. They are getting more lumens by making a larger surface.
Next would be CRI, or color rendering index. Which is an easy Wikipedia read, but in summary: the cool white LED is actually worse for depth perception and detail recognition than a good old incandescent. In fact, LED manufacturers make great strides to get LED color closer to incandescent. Color temperature and CRI often follow each other, but are not the same. A warm LED with the same 2700k color temp as incandescent will still never be 100 CRI. It is very expensive to build a high CRI LED, and also decreases the efficacy of the LED output at a given amperage in comparison to a "cool" white. In practice, high CRI (incan) also causes markedly less glare and eye strain than low CRI LED's (cool whites). A good way to think of this is this: 1 single high CRI (100) lumen is 100% effective to the human eye, while a low CRI (65) lumen is only 65% effective to the human eye. It's not quite that simple, but it's an easy way to understand. The 9011 bulb is 100 CRI (although lacking in the blue spectrum... blue is not desirable in night time driving anyways), while the LED in question is absolutely no higher than 80 (even if it was a high end warm Nichia bulb, which its not), it's more likely in the mid 60's.
Sure, LED headlight's lumen output is higher when it is measured at the emitter. However, I would wager that the candela measured at a distance of 100m from an LED (when installed in an incandescent reflector housing) is drastically lower than a good incandescent bulb in the same housing.
People are literally paying for less real world performance and reliability. To top it off, they are now blinding other drivers when they're driving around in their car with super cool LED headlights.
A cool way to understand how the reflectors are working is to grab a low powered flashlight, go out to your car, and really try to find the incandescent coil reflection in the reflector housing bands. You will see that it is almost like looking at the coil with a magnifying glass. Try the same with an LED, and you will see that you can see large areas of the reflector are engaging circuit board material, and entirely new areas of the reflector are engaging LED emitter from entirely inappropriate angles.
Marketing will have you think the LED emitters "are in proper placement"... sure they are, enough to sell a bunch of product. A final kick in the balls is that the Xenon Depot 9005 are merely rated to 1,750 lumens, meaning they have a very marginal increase over OEM 1,550 incandescent bulbs, with all of the draw backs of improper emitter placement and lower CRI, but they also have a MASSIVE 600 lumen deficit to the homely 9011 (at approximately 400% the cost of a pair of 9011.)
www.xenondepot.com
