LED Replacement Bulbs

[Rik Walter]

On 4/10/2021 at 8:15 AM, Paulkp said:

Not to pour cold water on your kind offer but note above.

Took all the LED Bulbs out for the MOT except the FOG LED's, 10 mins max.

[MetalAnon]

Forgive my nudging an aged thread, but I have read through the entirety and I have an issue, or more an inquiry for knowledge, that hasn't really been addressed beyond @Hamster suggesting it's a mess earlier in this thread. 

So I have a 2016 Sport that has the optional HID projector headlamps with auto high beam.  They suck, can barely tell they are on when under city lights at night.  This package uses a D3S xenon bulb rather than the H11 low beam and 9005 high beam in the halogen projector brethren.  The outboard bulbs are the D3S xenon's which shoulder both the low (dipped) and high beam duties.  The inboard bulb position is relegated to DRL which imho is a complete engineering fail... particularly with the Signature Lights on the Sport down below.  In researching possible HID to LED bulb upgrade, I have perused numerous threads implicitly poopoo'ing LED bulb use in projectors, more specifically, HID projectors.  I'm chiming in on this old thread in hopes to garner some theories from those with some experience and knowledge as to why halogen projectors apparently function sufficiently with LED Bulbs but the HID projectors do not. 

I have done extensive learning on the design issues with replacement LED Bulbs, in reflectors and projectors alike, the popular brand names as well as the cheapest Chinese but examples, though I am well aware I likely know a lot less then I don't.  I invite anyone with technical LED replacement/upgrade bulb knowledge to reply. 

Also, if anyone has disassembled the HID Edge projectors, I humbly request any insight as to how these things are designed to function exactly in switching from dipped beam to high beam.  I cannot for the life of me find a single page which speaks to their function.

TL:DR - How are the HID projector different from the halogen projector and can LED replacement bulbs function properly in the HID projectors (ie no glare etc)

PS. no intention to hijack this thread... just seeking knowledgeable brains to grok with.  Mods, should my reply here be in the wrong place, by all means move it accordingly.  I thank you ahead of time and look forward to any replies.

[Edge of Reason]

Can’t see anything wrong with your query, after all it’s an LED thread and that’s what you want. I’m not sure why LED Bulbs should not be fitted on projecter lights, but it might be to do with excessive heat build up, but someone else should give a definitive answer. I thought the fancy lights were supposed to be better than the crappy halogens in models without the all singing & dancing headlights. I’ve never heard anyone say they weren’t happy with them. 

[MetalAnon]

Thanks for the prompt reply @Edge of Reason and assurance in my own, reply that is!  😀

I think the problem has more to do the the beam patterns.  Being that LED chips have a tough time replicating exactly the light source of it's competitors and the reflector/projector assemblies are historically purpose built for those light sources, the patterns suffer.  I have well matched LED's in my Focus SE with the stock halogen reflectors and they are by far the most useful headlights I have ever turned on.   Huge improvement in night driving all around and they use a fraction of the DC the other bulb types use.  These darned projectors are just proving difficult to find any construction/design info about. Hopefully we can compile some geeky tech stuff together to find a grander understanding of this burgeoning technology. 

[unofix]

I can only add a little info to what has already been said but here goes:

The wavelength of the light from a HID lamp is totally diffrent to that of a Halogen lamp. The projectors in the respectful headlamps have a diffrent refractive index to focus the light. Replacing either type of lamp with an LED can create a problem with glare as the light leaving the LED is at a diffrent angle to the projector lenze compaired to the original lamp. In addtion to this the wavelenght of light produced by the LED is diffrent to that of either HID or Halogen, this can and does give the perception to those facing LED converted lights that the beam is more disperced.

You probably already know that converting your HID lights to LED will mean that it will fail an MOT test even if the beam pattern in correct.

[Paulkp]

On 9/9/2021 at 6:54 PM, unofix said:

The wavelength of the light from a HID lamp is totally diffrent to that of a Halogen lamp. The projectors in the respectful headlamps have a diffrent refractive index to focus the light. Replacing either type of lamp with an LED can create a problem with glare as the light leaving the LED is at a diffrent angle to the projector lenze compaired to the original lamp. In addtion to this the wavelenght of light produced by the LED is diffrent to that of either HID or Halogen, this can and does give the perception to those facing LED converted lights that the beam is more disperced.

And I bet you know how a Fresnel Lens works.......

[Edge of Reason]

Is that what they have in a lighthouse ?

[unofix]

It is indeed what they used to have in a lighthouse. Sadly Trinityhouse who looked after the lighthouses around the UK decided some years ago that lighthouses were no longer needed as ships and boats now all tend to have GPS and even small boats have radar. The actual lighthouses are still around the UK coastline and are used as a mounting point for transponder beacons (called Racon) which show up on a ships radar as a morsecode pulse.