Why LEDs should not be run in Halogen reflectors

This forum is awash with mis-information on lighting. Rather than trying to reiterate the same points repetitively to no end, I thought it would be beneficial to create a constructive educational informational thread for reference.

A disturbing trend has become to stuff LEDs into halogen reflectors thinking it is a plug and play replacement when it is about the offensive equivalent of putting an HID bulb in there for oncoming drivers. LEDs require projectors to control glare but will still be outperformed by halogens, here is why.

Chinese Opt7 7000 lumen LEDs vs German Osram 5800 lumen high powered halogens

LEDs:
For this experiment I chose the 7000 lumen OPT7 LEDs as they are very popular on the forum, advertise above average output for LEDs, and claim to have solved the LED product flaws to "outshine the rest". They also utilized smaller LED diodes than many others manufactures, meaning they had a better chance of mimicking a halogen bulb filament than the other manufactures using larger diodes. These are 6000k color temperature.

Halogens:
The halogens in this experiment are the 5800 lumen Osrams from the Ultimate headlight upgrade. These bulbs are over 100% brighter than stock while still maintaining reasonable bulb life. These are a significant light output upgrade without compromising optics by utilizing technology that is designed for the stock reflector halogen lens.

Interestingly LEDs usually rate lumens in pairs, while halogens rate them individually per bulb. Meaning these Opt7 7000 lumen LEDs are actually 3500 lumens each, compared to the Osram halogens rated individually at 2900 lumens each. To further muddy the comparison, LEDs are listed in 'raw' lumens, or theoretical lumens per chip multiple by the number of chips. Actual lumen output is typically near 1/2 the raw rating. Meaning that 3500 lumen spec is actually closer to 1750 lumens. But that is if they are a respectable high quality manufacture with reputable specs, many cheap Chinese LED manufactures are anything but.

While the diodes are in the approximate place they are not identical to the halogen bulb filament. The reflector is based on precise filament size and position, and having an omni-directional light source. The small changes to size and position will have significant consequences on beam pattern, this is why HIDs do not work in a halogen reflector. But more importantly, LEDs produce directional light fired at the sides of the reflector and will not illuminate the reflector surface uniformly like a halogen bulb resulting in performance loss. The upper rear portion of the reflector responsible for distance projection is very poorly illuminated by the LED design, which also results in loss of distance illumination.


It is easy to see the halogen filaments are on a hairline in the center of the bulb, and the LED diodes are significantly offset from center. Note also that LED light is directional, vs the halogen is omnidirectional, further compromising reflector optics.


Headlight upgrade done correctly:
Stock halogen on left (passenger), Ultimate 100%+ brighter than stock halogen on the right (driver). Yet to the oncoming driver these look nearly identical because the cut off horizon is maintained. I include these to demonstrate that it is not the light source being brighter that causes the issue.


Headlight upgrade done incorrectly:
LED on left (passenger), Ultimate 100%+ brighter than stock halogen on the right (driver). LEDs in a halogen reflector cause massive glare/scatter. The passenger LED light is not actually brighter, it has lost the horizon beam control due to improper optics, and is now emitting light above the horizon. This is known as glare. This is what blinds oncoming drivers. This is why you should not run an LED in a halogen reflector. This is a major loss in control and performance.


Wall test:
Halogen comparison
Ultimate halogen left (driver). Stock halogen right (passenger). For comparative reference. Though using a massive light output upgrade, the beam control is equivalent to stock.


LED comparison
Ultimate halogen left (driver). Opt7 LED on right (passenger) resulting in complete mess of a beam, lack of beam saturation with the loss of the cut off horizon, so much so it is even bleeding over the driver-side cut off horizon of the halogen. This is what blinds oncoming drivers. This is why you should not run an LED in a halogen reflector. There is zero resemblance of beam control. This is why a projector retrofit is needed to control glare with LEDs.


Measuring Lux output:
The 7000 lumen Opt7 LED, beam pattern was very spotty for headlight reading, likely due to hot spots and scatter in the beam. 419 Lux.


The 5800 lumen Osram halogen was a solid 609 Lux.


I actually thought it would be closer, the Chinese Opt7 LEDs failed to measure even remotely close in output to the German halogens, despite their significantly higher manufacture lumen rating.

Since Osram is one of the most respected world leading manufactures in lighting technologies, and trusted to be original equipment by many OEMs including Toyota, I would speculate the lumen output of the LEDs is vastly overstated. Which would not surprise me for cheap Chinese LED manufactures. However, it could also be the halogens had a focused concentrated beam since the reflector optics are designed for that light source so they were able to put out much better numbers.

Pure Output:
5800 lumen Ultimate on left (driver), vs 7000 lumen Opt7 LED on right (passenger).


Superior cut offs, with superior continuous flood of light and more measured light output. Using a halogen upgrade in a halogen reflector is the correct solution for those that want a high performance headlight upgrade in their halogen housings. Using a projector retrofit for LEDs will control glare, but will not increase output and result in a performance downgrade as pictured above.

The LEDs also instructed the user to run without headlight boots, as the boots cause the LEDs to overheat. However if you remove them condensation inside the lens in going to be an issue. It did say you can modify your boots to reuse them, but must cut adequate air holes in them or headlight failure would occur. Which makes them completely useless as the seal is lost.

Halogens are a dated technology, but they are what the stock headlights are designed to utilize. To move to a new lighting technology platform, you must move to a compatible lens design, meaning you cannot just swap out the light source without also considering the headlight assembly design.

Numerous LED companies have started claiming that their LEDs can be run in halogen reflectors because of their "new design".

Yeah...

LEDs do not uniformily illuminate the reflector or internal projectors reflector housing. They are only shining light to the sides. Uniform lighting is critical in uniform beam pattern projection. The worst thing you could do is not illuminate the upper portion of the reflector/projector most responsible for projecting distance down road.

LEDs
The bi-directional design does not illuminate the upper portion of the reflector to project light down road...



Hikari H4s new design promises to have fixed the LED design issues.
Glare. Note that the driver side halogen light is upgraded to over 2x over stock but produces no increased glare even though it is significantly brighter than the LED and also projects light further than the passenger side LED.



While the high power halogens with the correct optics provide full pattern high intensity light output on the left, the LEDs barely illuminate the anything on the right due to the incorrect optics.


But LED output is supposed to be great, the whiter light must be better? No.



Halogen reflectors are designed for halogen filament base lights. LEDs as much as they may try to replicate a halogen source are not one. A halogen upgrade in a halogen reflector is vastly superior, as the entire design is based around projecting a halogen light source. An LED moves the light source out off center and does not uniformly light the housing completely defeating the precision optical design of the housing to gather the light and focus it into a hotspot to project it down road. The results are loss of the hot spot, which means loss of distance projection.

Hikaris Philips Lumileds. These now "replicate the halogen filament".
More of the same.
The halogen light on the right is 2x brighter than stock and actually brighter in the beam pattern area than the LEDs on the left. Again. But loss of beam control introducing massive glare makes the LEDs look brighter in photos and causes people to see this as an 'upgrade'.



deAutoLEDs that claim "no glare" for reflectors
deAutoLED in the 2nd gens Fogs vs H9 halogen upgrade (which is 2x brighter than stock)

Glare in the fogs compared to an upgraded halogen light source that maintains beam control even though it puts out 2x the light.



While not in a halogen reflector, this demonstrates the importance of SAE beam pattern and beam control.

Rigid SAE fog pods vs Baja Designs wide-corning pod.
Both are near equivalent in output, what you see is purely lack of cut off in the beam pattern. Rigid employees real SAE cut offs to not blind other drivers and puts down higher output numbers in the desired beam pattern region. If the light is being wasted on the air, it is not being utilized on the ground.



Some of these hack products may actually put out more lumens than performance halogens. What is important to understand is if the product is any wider than the tiny halogen filament you will see a dilution in hotspot or loss of one all together. This will shift the beam pattern toward the vehicle and cause a significant loss in distance projection and distance visibility. Not illuminating the upper portion of the housing only makes things even worse by not creating a fully saturated pattern and ending up with an inconsistent one. Meanwhile all the foreground light from shifting the pattern toward the vehicle causing drivers eyes to constrict further compounding the problem by reducing night vision. The off center shift of the light source will also cause increased glare. Unfortunately all this also makes for great "before/after" photos with the intense near field lighting and maybe some dazzling glare leading many misinformed people to believe they have somehow helped themselves when they have actually very much hurt their night vision ability.

LEDs in Projectors
Eliminating the glare part of the equation by using 3rd Gen projectors, how do LEDs compare? I've posted plenty about loss of focus with LEDs and figured a solid example would be helpful in illustrating the issue.

Recall halogen optics work by concentrating a beam into a hotspot to project distance. Lack of a hotspot or reduction of hotspot equates to lack of distance projection and a pattern shift of moving the light pattern toward the vehicle, which aside from greatly reducing distance projection also increases foreground light which constricts pupils to further reduce night distance vision. Hotspots and distance projection is increased by making light sources smaller and more precise to increase optical focus to project the light further. While you want more light, you want the more light projected further down road, not more light in a blob immediately in front of you.

Stock wattage H11 GE Megalight +130 performance halogen on the Left vs XD Pro high output LED right


While the LED actually has a higher lumen output rating, focus is completely lost. Hotspot is eliminated and distance projection is lost. The pattern has shifted from projecting distance to high foreground lighting, which as mentioned above is not a good thing.

You can see the halogen filament on center, with reflections off the rear of the projector concentrating the light into a focused hotspot. And recall smaller light sources create better focus for higher intensity.


Compared to the LED, there is no center focus at all. It is difficult to say if those even reflect off the back of the projector since they are side firing, but for focus you should have light in the very center of the housing, and it is absent. Affect on the beam is predictable.


So what does this mean for output? See earlier photo for pattern.

Using a professional grade LED compatible light meter:

XD Pro LED:



Stock wattage H11 GE +130 performance halogen:


Not even close. The stock wattage performance halogen is appearing to burn a hole through the door with the highly focused projected distance lighting while the LEDs are providing more of a generalized short range flood light, which is not what you want in a headlight. The headlights primary purpose is to see distance.

GE adds the blue tint at the back of the bulb, so that the edges of the beam get the blue appearance that many are looking for without affecting the output by filtering the primary beam pattern with blue tint.

Somewhat difficult to tell in these photos but the halogen beam arcs down on either side of the hotspot, with the LEDs it arcs upward on either side of where the hot spot would be if there was one, because the light sources are moved off center. Not helpful to oncoming drivers.

GE Megalight +130 bulbs used in this test:
https://www.powerbulbs.com/us/product/ge-megalight-ultra-h11-twin


What about switching to 'LED housings'?
LED pod lights are popularly placed in the OEM fog location, leading people to falsely think they are a "fog light" when depending on the pattern may be far from it. See why pod beam patterns are important and how to choose the correct pattern here:
https://www.tacomaworld.com/threads/the-led-sae-j583-fog-pod-fog-light-review.554813/

If you found this interesting you may be interested in my other lighting threads.

Fog light upgrades:
The LED SAE J583 Fog Pod & Fog Light Review
The ultimate foglight upgrade H11 (not LED or HID)
The H10 to 9011 HIR Foglight upgrade (better than LED)

Other lighting upgrades:
3rd Gen HID vs LED vs Halogen H11 projector headlights
The ultimate headlight upgrade H4 (not LED or HID)
Gy6.35 HIR 921 reverse light upgrade (vs high power LEDs)
The 921 LED Reverse Light Bulb Study

Rock Lights:
The Rock Light Showdown

More information on automotive lighting:
Automotive Lighting 101

Home lighting upgrades:
High quality efficient home lighting using LEDs, HIRs and Halogens

I am always happy to help anyone on their truck project. Please do not hesitate to PM me with your questions or post them here.

 

Good info, sadly it goes in one ear and out the other like the OEM balljoints.

 

Good info and thanks for the time investment.

Sadly, people will continue to jam any non-halogen bulb in a halogen housing because doing it right costs a lot (I'm referring to retrofitting a projector). Or, many are intimidated by the wiring aspect of the Ultimate Headlight upgrade you referred to.

 

My hope was that with a dedicated detailed thread to break down why it is not a good practice, the information would have more staying power.

 

Fantastic thread and pics. Gonna repost this.

 

I tried those Opt7 LEDs in my truck and returned them the next day. The beam pattern was garbage, and blinded every other driver coming toward me. I live in a neighborhood of Brooklyn where everyone has switched to LED or HID lights in their reflector housings, and it's just constant blinding on the road. "I can see everything better" is the common statement by these goons.

 

Very informative!!

 

Great easy to read write-up. Thanks for sharing your subject knowledge.

 

Any word on LED's and HID's in a OEM Halogen Projector like what comes on the 2016 Tacoma? I have a 4Runner now with the OEM Halogen Projectors and would like whiter light. Is there a difference between HID projectors and Halogen Projectors?

 

+1 rep to OP

 

Guess I'm taking my test Cali Raised LED's out. Like everyone says they are bright, and I have them more aimed towards the road. But the scatter is still very prevalent. Back to my Sylvania ZXE's I guess

 

Excellent question. In short yes and no.

The nature of the projector design should maintain a good cut off, so you shouldn't blind other drivers. However as demonstrated in the last picture in the thread, there is also consistency and fullness of the beam pattern to consider. By going to an alternative light source you are changing the optics, and even though the cut off can be accounted for you may end up with hot spots in your pattern, rather than a full uniform beam.

Good additional reading on the subject:
http://www.danielsternlighting.com/tech/bulbs/Hid/conversions/conversions.html

For whiter light and a significant lighting upgrade in the halogen projector, I would recommend looking at my foglight thread. It runs H11s like the 3rd gen projectors, and can be applied to H11 projectors. It will maintain the perfect full uniform beam pattern of the halogen it was designed for. There are links in the thread to whiter high powered bulb options compared to the stock colored H11 Flosser bulbs I used.

 

My brother replaced his halogens with HIDs in his Crossfire projectors, and I notice significantly more glare than my Mini H1 7.0 retrofits, but much less than HIDs in halogen reflectors. It also does not light up the road that much, though that may also be due to him using 6000K HIDs vs my 5500K HIDs. Cutoff is also nowhere near as crisp.

 

His projector doesn't have a clear lens, most stock projectors have swirls or a haze in the lens.

 

Which really would only affect the crispness of the cutoff. Also, the term you are looking for is frosted lens.

 

That's it. I've seen some though that have swirls too, slight dimples also.

 

Love the write up.

The whole light change craze is running nuts, based on 'cool' or 'I heard'. Reminds me of the Altezza, clear side markers, PIAA projectors and all that nonsense of the '90s. Then the 'blue light HID' copycats of the '00's, fueled by little boys in their bouncy slammed-via-chopped-coil-spring rice-a-roni rides. The ones with the grapefruit launcher exhaust tips.

The spiffy thing about your 'ultimate' options (heads and fogs) is that you get PLENTY of light for driving at any legal road speeds w/o offending others, because it's aimed in the right direction. There is no kluge with wiring/ballasts blah blah blah.

And if you are a true off roader, or live in a moonless rural area with no neighbors, the Tacoma has a plethora of other ancillary lighting options that will do great.

 

So what's the nicest and best halogen bulb to get? Had PIAA to me they sucked and have off that blueish hue