LED Headlights - anyone?!

[PIGINAWIG]

Hi All,

Just received a marketing Email from those bods at BMW regarding the new 6 series 4 door, available June 2012 and it says that 'LED' headlights will be a option on this vehicle. I'm not going to buy a new 6 series but wondered what technology it utilises?

I know what LED'S are - widely used in rear lights and DRL's etc - but how the heck do they make them so powerful as to illuminate the road that much?!

Impressive stuff indeedy. Low current draw and last for ages. Anyone got further info on them? (apologies if this thread has been done before)

Cheers.

PIG.

[MC Bodge]

LEDs in a small housing and driven by a small battery are great for mountain biking night riding.



Scaled-up and fitted into a car headlight unit there would be a lot of light.

[morgrp]

When run through a projector lense to focus the light they would be awesome - google LED Lenser to see how effective they are -I've often wondered why they haven't done this before - guess the diode technology wasnt good enough unil recently. Great idea as the diodes will almost certainly out live the car, then all the dick heads driving around at the moment with bulbs out wont annoy me. I think Volvo were the first with the s40 - had led brake lights

Edited by morgrp on Tuesday 20th December 11:57

[RZ1]

Just take a look at LED torches, the light some of them give is insane, and they are not very big either.

[PIGINAWIG]

That push pike has some serious lighting power!

Well, if Bmw are using a system it must be well tested and effective. Won't be long before the Saxo's and corsa's get a retro fit sytem from China....

[inman999]

Think the Lexus LS600h has had them for a couple of years and the R8 V10 too.

Getting rid of the heat has been an issue IIRC.

[Pistachio]

Biggest problem in winter with LED headlamps is that they dont melt the snow of the headlamp lens as they don't get that hot like halogen bulbs.
They have had trouble in Canada with new traffic lights that are LED
Apart from that I think they are amazing.
http://www.engadget.com/2009/12/17/led-traffic-lig...

[XVar]

inman999 said:

Getting rid of the heat has been an issue IIRC.

Pistachio said:

Biggest problem in winter with LED headlamps is that they dont melt the snow of the headlamp lens as they don't get that hot like halogen bulbs.

Hmm...which is it then?

[morgrp]

Pistachio said:

Biggest problem in winter with LED headlamps is that they dont melt the snow of the headlamp lens as they don't get that hot like halogen bulbs.
They have had trouble in Canada with new traffic lights that are LED
Apart from that I think they are amazing.
http://www.engadget.com/2009/12/17/led-traffic-lig...

I always clear my lighs before I set off anyway - whilst on the move my headlight wipers do the job - they'll have to bring back eighties tactic head lampwipers!

[cheadle hulme]

The new Ducati Panigale has them too.

I've had Hope and Fenix jobbies on my pushbikes for years. Great for waring your fingers on in Winter too!!

[mrmr96]

inman999 said:

Think the Lexus LS600h has had them for a couple of years and the R8 V10 too.

Getting rid of the heat has been an issue IIRC.

What heat? LED's run cool, it's one of their advantages and the reason why they don't use as much power.

[mrmr96]

XVar said:

inman999 said:

Getting rid of the heat has been an issue IIRC.

Pistachio said:

Biggest problem in winter with LED headlamps is that they dont melt the snow of the headlamp lens as they don't get that hot like halogen bulbs.

Hmm...which is it then?

LED's run cold.

[Trustmeimadoctor]

mrmr96 said:

LED's run cold.

since when lol
http://en.wikipedia.org/wiki/Thermal_management_of...

[MC Bodge]

mrmr96 said:

XVar said:

inman999 said:

Getting rid of the heat has been an issue IIRC.

Pistachio said:

Biggest problem in winter with LED headlamps is that they dont melt the snow of the headlamp lens as they don't get that hot like halogen bulbs.

Hmm...which is it then?

LED's run cold.

Heatsinking the LED circuitry to keep the temperature down is important.

The bike LED lamps have metal bodies to help dissipate the heat. It shouldn't be a problem with a steel car if there is a good connection between the body and the lamp.

[mrmr96]

Trustmeimadoctor said:

mrmr96 said:

LED's run cold.

since when lol
http://en.wikipedia.org/wiki/Thermal_management_of...

Umm... ok. I guess it depends on the type of LED.

The little ones used in the cluster on the traffic light won't heat up, as each small one runs cool.
But the big ones (like one single massive one) used in a headlight runs hot I guess. (I didn't know that.)

So I think I'm right in saying that (small) LED's run cool, but you've correctly pointed out this isn't true for the big ones.

[Trevelyan]

mrmr96 said:

LED's run cold.

I can assure you they don't. I've got similar LED lights to the picture above fitted to my Mountain Bike. Despite the lamp housing being one large aluminium heatsink they still get very hot to the touch. If the bike is stationary for a while meaning the lights don't get any airflow for cooling they actually automatically reduce in output power to prevent themselves from damage by overheating.

[Pistachio]

XVar said:

inman999 said:

Getting rid of the heat has been an issue IIRC.

Pistachio said:

Biggest problem in winter with LED headlamps is that they dont melt the snow of the headlamp lens as they don't get that hot like halogen bulbs.

Hmm...which is it then?

It is all to do with the PCB heat sinking and the actual ambient heat. Often the led is shining from a distance through a lens and the PCB is further back so the light emission is not hot, just the light source ….I think…Help is there a lamp specialist out there I need to borrow his shovel.

[SWoll]

XVar said:

inman999 said:

Getting rid of the heat has been an issue IIRC.

Pistachio said:

Biggest problem in winter with LED headlamps is that they dont melt the snow of the headlamp lens as they don't get that hot like halogen bulbs.

Hmm...which is it then?

There's only one way to find out........

[essayer]

The LED itself does not get hot but the power regulation circuitry does.

[Mr2Mike]

mrmr96 said:

So I think I'm right in saying that (small) LED's run cool, but you've correctly pointed out this isn't true for the big ones.

All LEDs dissipate some heat since they do not convert all the the input power to light. Small 3mm or 5mm LED's tend to be thermally limited because they are in plastic packages that have very high thermal impedances, which is why you don't get high power LED's in this style of package. However, even these small LEDs can get noticeably warm running at their maximum rated current.