Brightness of lights - a question, not a whinge

[AW111]

Ok, so there already a brake light thread for bickering on here: http://www.pistonheads.com/gassing/topic.asp?h=0&a...

I have a question : is there a regulation / design rule that relates to the light output of lights (including indicators etc)?
The bulb sizing by power, eg 21w for brakes, works fine with incandescents, but a 21w LED is a whole different kettle of fish.
Similarly, I am not supposed to run 100w halogen headlights, but 60w HID or laser headlights are much brighter.

TL;DR; Does anyone know if car manufaturers have a limit on light output or intensity?

[Jader1973]

Yes there is. The relevant ECE and FMVSS regs have rules for visibility and luminosity.

[AW111]

Jader1973 said:

Yes there is. The relevant ECE and FMVSS regs have rules for visibility and luminosity.

Ok, thanks. I knew there we regs on veiwing angles and minimum visibilty, I wondered if there was a max intensity, and if so, what it is.

[Blaster72]

http://www.hella.com/hella-com/assets/media_global...

Looks like just high beam has a limit on output.

[Vanin]

I know that some cars from the 60s and 70s had dimming relays for indicators and maybe brakes when the headlights were turned on. Don't know if this still happens
This is from Triumph Stag blog

"Check for iffy electrical connections, bad earths and sticky switches, as these are the main problems. Problems can arise if less than ideal modifications have been made to fit accessories like stereos and alarm systems. If the brake lights appear dim then the night dimming relay could be to blame. The relay is a BL addition, situated in the front left corner of the boot compartment behind the trim; it dims the brake and indicator bulbs when the sidelights are on."

[996TT02]

AW111 said:

...eg 21w for brakes, works fine with incandescents, but a 21w LED is a whole different kettle of fish.

A detail perhaps, but you are unlikely to encounter a 21W LED.

[AW111]

996TT02 said:

A detail perhaps, but you are unlikely to encounter a 21W LED.

True, but technically I could fit 4 x 5w crees in each brake light, and cause PH to melt down if ever a member was behind me when I stopped.

Then again, I think the LED headlights are around 20 watts. A pair of them on the back, and one in each indicator should do it.
I'll keep the 5w crees for tailights and parkers.

[AlexIT]

Re: tail lights with LEDs the average power is
2-3W for tail lights
4-5W for stop lights
3-4W for D.indicator
5 W for both fog and reverse

I must check back at work on the homologation documents, but IIRC for all lights there is a very precise range of luminescence and viewing angle it must comply to.
If I don't forget it, on Monday I give a look and report back

[mikal83]

AW111 said:

Ok, so there already a brake light thread for bickering on here: http://www.pistonheads.com/gassing/topic.asp?h=0&a...

I have a question : is there a regulation / design rule that relates to the light output of lights (including indicators etc)?
The bulb sizing by power, eg 21w for brakes, works fine with incandescents, but a 21w LED is a whole different kettle of fish.
Similarly, I am not supposed to run 100w halogen headlights, but 60w HID or laser headlights are much brighter.

TL;DR; Does anyone know if car manufaturers have a limit on light output or intensity?

Its not just that thread mate, it comes up every 5 mins with the petrol v diesel, electric handbrake, non indicating, driving with iced up windscreen, winter tyres and a few other subjects.

just waitn a while and it'll come around again.

[fangio]

Regardless of specs., rule 114 bars just about every drl ever fitted! The only thing is who decides if you are dazzled? Surely, you?

https://www.gov.uk/general-rules-all-drivers-rider...