Why LEDs should not be run in Halogen reflectors

So.. I'm one of those guys who wanted more light, and slapped some LED's in. They're brighter, but the light is so scattered and has no real decent projection down range . I wasn't really sure what was going on until I read OP's post. Makes perfect sense now. Just going to get some decent halogens: PIAA or Philips or something. Thanks OP!

 

Check out the ‘Other Bulbs’ section at the end of this thread:
https://www.tacomaworld.com/threads/the-ultimate-h4-headlight-upgrade-not-led-or-hid.398066/

I’d recommend the Philips Xtreme +130 if looking for a stock wattage replacement.

 

Yes, I agree. Totally an awesome discussion. Thanks much for the learning.

 

That is a 2016+ (3rd gen) which use a projector, not a reflector as covered in this thread. The 3rd gens do use reflectors in their fogs and high beams.

Projectors have light shields to give clean cut off regardless of the light source used, but cut offs are only one part of the light equation. Even with a projector you can actually see in the video the loss of the low beam hot spot comparing the halogen to the LED, which will result in loss of light distance projection or what people like to call “throw”. Clear as day. Also note the loss in the lower portion of the LED low beam with a large dark region in the center, this is due to the side firing LEDs mounted on a rod in the housing not uniformly lighting the projector as it was designed for an omni-directional halogen light source. You also have upward glare on the sides which should have clean cut offs like the halogen, again thanks to the side firing LEDs. In short that beam is a mess.

 

You're not addressing the HB demonstration in which the LED bulb performed better than the halogen in a reflector lens.

Kirk Out

 

So how about you share the link?

 

The link is right there in crashnburn80's post. Right above my post. In the quoted text....the vid by headlight revolution...Kirk Out

 

Out of curiosity, would an LED bulb with 360 degrees of light output be equivalent to a halogen in terms of its effects on the overall optics of the lighting system? Something like this:

https://www.superbrightleds.com/mor...ime-running-light-bulb-28-smd-led-tower/1278/

 

No, but good question. The omnidirectional light is only part of the issue. The reflector housing is designed to redirect and project light emitting from the very precise point of a halogen filament. It is a high precision geometry game. That style bulb you link has light coming from all sorts of different places, none of which is where the reflector is designed to take the light source from.

Imagine a game of pool, where your ball is at one end of the table and you make a precise shot bouncing it off the wall and into a pocket at the other end of the table. Now redo the shot at the exact same angle and direction but put the ball in a completely different spot on the table. It won’t make the pocket because your previous shot was based on the balls starting point, much how moving the light source will no longer correctly bounce it off the reflector to form the beam pattern. And with that light you linked you’re now firing 27 different shots all from wrong locations. It results in a mess.

Also note those style bulbs are dangerous as they put out practically no usable light. Raw lumen spec is about 600, meaning actual lumens is likely less than 300. The stock bulb is 1,300 lumens. If you read the fine print there is even a warning on the site that the bulbs won’t work as a fog light and should be used for cosmetics only. Combined with the bad reflector optics it would put almost no usable light on the road.

 

I've never seen an LED bulb do 360 properly like an HID bulb.

 

Thanks for the reply.

I understand the importance and minimal tolerance of the lighting geometry but wasn’t sure if a 360 degree bulb would negate that. I remember seeing a nice diagram online somewhere (maybe on a Jeep forum about a similar topic) that showed the emission pattern of incandescent, led, and hid bulbs to show that the light sources are very different. The point of it was to show that the incident angles of the light rays varied quite a bit between the three.

To Tony2018, I think you would have the same issue because of how the light is emitted from an HID compared to halogen/incandescent.

 

Here's a similar diagram

 

Here’s my pic of stock halogen compared to a set of quality leds on my garage in a Holgen housing didn’t think much of it at the time. I saw brighter light from lens an thought better, till I learned about how it reflects an now I know better.

 

Here’s a pic of just the headlights with harness an osram 90/100w bulbs.



This photo is of leds you can see how it reflects off the signs even worse for other drivers

 

Unfortunately most see the hyper reflective signs and attribute it to their lights must be super bright, not their lights must not be controlling the beam pattern.

Short wavelength light of LEDs also refracts more, causing surface glare. Surface glare does not illuminate things better, it just means the light bounces and scatters back at the driver. Which is why LEDs do not do as well in rain/snow/fog, but it also causes street signs to be reflected more intensely.

 

I was one of those till I read your thread an it made crystal clear sense to me.

 

So glad I found this info. before spending more of my money. I've been pissed trying to figure out what is wrong with my crappy reflection and after reading this it makes perfect sense now. I am taking my LED's out and getting Halogens in again. Thanks man

 

Good info! Thanks!

 

I switched back to halogen nearly 2 years ago - due to op's first post creating this thread (i ordered my halogens on 10/16/16). I was not going to be responsible for a family plowing into someone because my 'cool' LED headlights blinded them.

FFWD to today. I am also now re-thinking my taillight/brakelight choice. Going back to halogen there as well. I have been running these since May 2016 (no longer available):

https://www.amazon.com/gp/product/B01B7L19LE

While I was thrilled back when I installed them, it has always 'bugged me' a little that they were REALLY bright. I can't stand blinding brake lights, really gets to me. Time to not be that a-hole as well. So, will replace them with Halogen or some more conventional LED but probably halogen. Will keep reverse lights LED. Rear turn will probably leave as well. In front, I did the turn signal to DRL/turn using a switchback LED so that will stay as well.

@crashnburn80 - excellent thread. Two years ago you helped to throw some light (lol no pun intended) on LED use. Thanks sir.

 

This is great info and should be posted on all car forms, the amount of modified cars with upgraded lights (done incorrectly) that blind other people is a danger to everyone around them. Thanks OP for the easy to read and understand information!!