LED Bulbs

[SILICONEKID345HP]

Just purchased two led cree 80 watt bulbs for the stop /tail lights .I think they are wrong .

Should the correct one`s have twin filament with staggered pins ?

These are the one`s I ordered but they seem to be different.
http://www.ebay.co.uk/itm/370968345463?_trksid=p20...

Edited by SILICONEKID345HP on Tuesday 1st November 20:08

[FlipFlopGriff]

Those are twin filament. From memory the Chimp ones are rear and brake light combined but pins are opposite and not offset. Cant recall the number but I had 2 ordered by mistake - luckily they fit the Land Rover I've just bought. Think its 382 or BAY15S???
The Griff ones are light and fog combined and BAZ15D, as was my dads 2001 Octavia..
FFG

[Dr Mike Oxgreen]

You should be buying RED ones for the stop and tail lights.

If you buy white ones, the red filter in the light fitting will filter out the blue and green components of the light, thus the light output will be much lower. However, if you use red LEDs, they emit all their power as red light, which will all pass through the red filter.

So yes, the ones you've bought are definitely wrong, because they're the wrong colour for starters.

Buy RED ones, not white ones.

[Dr Mike Oxgreen]

These are the ones I bought. They're the correct type, and they work. And they're red.

Trust me, if you put white LEDs behind a red filter, the result will be significantly dimmer than if you put red LEDs behind the red filter.


http://www.car-mod-shop.co.uk/380cree-80-rx2-pair-...

[Dr Mike Oxgreen]

And if you want to do the indicators as well, here's a link to the thread I started. You'll need the amber 382 version of the bulbs, and you'll also need to replace the flasher unit otherwise they flash too fast. All the details of what to buy and how to do it are in the thread.


Oops - the above link is wrong. Here's the right link: http://www.pistonheads.com/gassing/topic.asp?t=142...

Edited by Dr Mike Oxgreen on Wednesday 9th November 07:07

[SILICONEKID345HP]

I wonder why the standard ones im replacing are clear.

[Dr Mike Oxgreen]

SILICONEKID345HP said:

I wonder why the standard ones im replacing are clear.

Because there's no such thing as a filament that emits red light, so with filament bulbs there's no alternative but to fit white bulbs behind the red filter. Sometimes bulbs have a red pigment on the glass, but that amounts to the same thing - the filament itself emits whitish light.

For LEDs, it's different. The semiconductor is 'doped' with special impurities to make it produce a particular colour of light. A red LED will be doped with just the substance that makes it produce red light, whereas a white LED has some of the 'red doping, some of the green doping and some of the blue doping (white light is essentially a mixture of red, green and blue). A white LED therefore only produces about a third of its power as red light - the other two-thirds will be wasted if you put it behind a red filter.

Incidentally, it's only in recent years that it has been possible to make LEDs that can emit blue light. It took a long time for someone to discover the right doping substance to make blue light, and without that you can't make an LED produce white light. I believe the chap who discovered the 'blue' doping was given a Nobel prize quite recently.

Edited by Dr Mike Oxgreen on Wednesday 2nd November 07:42

[FlipFlopGriff]

Yes they need to be red for rear light/brake light. Forgot that bit.
FFG

[Dr Mike Oxgreen]

You'll probably find that you can only buy the combined stop/tail LEDs in red. I can't think of a reason why they'd make them in white.

[FlipFlopGriff]

Dr Mike Oxgreen said:

You'll probably find that you can only buy the combined stop/tail LEDs in red. I can't think of a reason why they'd make them in white.

The Griff brake light is separate and the rear light is combined with the fog light. The Chim one works great on the Land Rover though - really bright and looking to change the other LR bulbs to LED as the lights are tiny and they aren't bright.
FFG

[Rob_the_Sparky]

Dr Mike Oxgreen said:

These are the ones I bought. They're the correct type, and they work. And they're red.

Trust me, if you put white LEDs behind a red filter, the result will be significantly dimmer than if you put red LEDs behind the red filter.


http://www.car-mod-shop.co.uk/380cree-80-rx2-pair-...

Correct but I have often wondered why when LEDs are so much more efficient at converting power into light why do you need to INCREASE the power consumption of your bulbs from 21W to 80W? To even use the same amount of power in an LED light should produce far more light, even before accounting for the filter losses encountered when using a filament bulb. Are you not in danger of having tail lights that are so bright that they look like brake lights and then just blinding people with your actual brake lights?

[TwinKam]

Think you'll find there's a law concerning the 'brightness' of tail lights, number plate lights etc. 5W (tungsten). Likewise brake lights at 21W (tungsten). Guess these LEDs aren't e-marked and therefore not approved for highway use...
Noticed a lot of Audis & Beemers with visible LED number plate 'bulbs' recently. What the hell is that about? Bling? I want my number plates to be as dimly lit as legally possible! Besides, 'Showing a white light to the rear' (whilst the vehicle is in forward motion) is an endorsable offence IIRC.

Edited by TwinKam on Wednesday 2nd November 15:01

[N7GTX]

These regulations seem to be saying that if the lamp unit has an approval mark then they can only be fitted with filament lamps if used on vehicles made after 1/4/1986. I assume that the original upside down Ford Fiesta rear lamp units are covered by this.

Filament lamps
14.—(1) Where a motor vehicle first used on or after 1st April 1986 or any trailer manufactured on or after 1st October 1985 is equipped with any lamp of a type that is required by any Schedule to these Regulations to be marked with an approval mark, no filament lamp other than a filament lamp referred to in the Designation of Approval Marks Regulations in–
(a)regulation 4 and Schedule 2, items 2 or 2A, 8, 20, 37 or 37A; or
(b)regulation 5 and Schedule 4, item 18,
shall be fitted to any such lamp.

White lights to the rear:

(2) No vehicle shall be fitted with a lamp which is capable of showing any light to the rear, other than a red light, except–
(a)amber light from a direction indicator or side marker lamp;
(b)white light from a reversing lamp;
(c)white light from a work lamp;
(d)light to illuminate the interior of a vehicle;
(e)light from an illuminated rear registration plate;
(f)light for the purposes of illuminating a taxi meter;
(g)in the case of a bus, light for the purposes of illuminating a route indicator;

The Road Vehicles Lighting Regulations 1989

Phew, its confusing....

[RobXjcoupe]

Just out of curiosity, why fit led bulbs behind regular light clusters? If you fitted clear clusters I understand but behind a standard unit seems a bit of a waste, don't you think?

[Dr Mike Oxgreen]

Whatever these LED bulbs are, they are most definitely not 80W. That would be an insane amount of light, and they would also melt the wiring for the brake lights and/or tail lights. And they're not "80W equivalent" either, because that would be far too bright for stop/tail lights. They're nowhere near as bright as 55W halogen headlights, for example.

They're somewhat brighter than the glimmer you get from standard bulbs in these light fittings, but the bulbs I've linked to are certainly not excessively bright. The 80W claim is definitely misleading, but I don't care. They are simply good, sensible replacement bulbs. The brake lights operate much more 'crisply' than conventional filament bulbs, so they draw the attention of a following driver better.

Edited by Dr Mike Oxgreen on Thursday 3rd November 06:49

[Dr Mike Oxgreen]

RobXjcoupe said:

Just out of curiosity, why fit led bulbs behind regular light clusters? If you fitted clear clusters I understand but behind a standard unit seems a bit of a waste, don't you think?

Not really. As I've tried to explain, because red LEDs generate all of their power as red light, virtually all of this light will pass through the red filter. The filter is superfluous, but won't be reducing the brightness of the bulbs by very much (except if you mistakenly buy white LEDs). You could remove the red filter and replace with a clear one, but why bother?

[Bassfiendnoideawhathp]

Dr Mike Oxgreen said:

<<SNIP>>

The brake lights operate much more 'crisply' than conventional filament bulbs, so they draw the attention of a following driver better.

I've never really found the response times of a filament bulb to be a problem...

[FoxTVR430]

I think that the LED companies are trying to get "one up" on their competition by saying that their LED produces 80W of light. (more is better ??)
This does not mean that it consumes 80W of electricity, otherwise as others have said our wiring could melt .
But that the LED produces an equivalent of 80W light intensity of a normal filament lamp. So in other words a very (maybe too) bright light.

[FlipFlopGriff]

Another benefit is that the LED brake light comes on fractionally sooner than a conventional bulbs which must be a big positive to warn following drivers.
FFG

[TwinKam]

I agree that they appear more 'digital' in their switching but not sure whether a few milliseconds quicker response when you hit the middle pedal grabs more attention from the following driver?... who at night has already been completely dazzled by your 2x'56'W* of tail lights (plus your LED floodlit number plate...) Nope, I think these COB/SMD (yellow square) types are far too bright in these applications.

I have fitted an (old skool bobbly type) LED stop/tail on my bike (a vibrating jackhammer known as a Buell) simply because LEDs withstand vibration better than a tungsten filament bulb. It is not appreciably brighter, just more reliable (in this application).

• Cree say side light output on an LED 380 equiv is 70% of '80'W and brag it's "bright as a headlamp".