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[Marks DTM Calib]

As a more tech tip, when putting together LED clusters for such use, ensure you have a series rectifier diode with a good reverse voltage figure (e.g.a 1N4004 or better) as LED's dont like reverse voltage (and as we know, car power supplies are 'orrible' with lots of transients). 

[aaronjb]

All it would take is a "I couldn't see his brake lights, Officer", I suppose

Somebody on another forum posted an interesting observation.

If you are unlucky enough to have suffered a rear end accident (Oo-er missus) the police can often determine if you were braking at the time by looking at any burnt out bulb filaments that have been subject to the atmosphere when the glass breaks -

Not something you could determine with LED`s

Food for thought I suppose ?
 :-/

An interesting point, that, Dave! Although it won't help with kit cars, I imagine with the very latest cars they can just plug into the onboard computer and ask it if the brakes were on at the time of impact..

[Dave DND]

As a more tech tip, when putting together LED clusters for such use, ensure you have a series rectifier diode with a good reverse voltage figure (e.g.a 1N4004 or better) as LED's dont like reverse voltage (and as we know, car power supplies are 'orrible' with lots of transients). 

 

Good tip !!  Must admit, I hadn`t considered that !

 

[lee4206]

Hi Dave. From a mot point of view as long as they function as they're supposed to and they don't interfere with each other then its a pass. We don't measure brightness or angle so that's not an issue.

[Dave DND]

Hi Dave. From a mot point of view as long as they function as they're supposed to and they don't interfere with each other then its a pass. We don't measure brightness or angle so that's not an issue.

Do I take it that you are an MOT tester ?

If so, imagine this scenario -
You are testing a tail light that is incredibly dim and dark to the point that your eyebrows are raised and you think about failing it as it could be dangerous - I am not questioning your decision, nor powers to do this, if you think this is a safety fail, then rightly so -

However, if the owner of the car disagrees and says, "Oh no it isn`t" - where do you go from there ?

what guidelines / information / powers that be, have the final definative say on this, as I`m really struggling to satisfy my curiosity on this now.

 :-?

[lee4206]

Hi Dave. From a mot point of view as long as they function as they're supposed to and they don't interfere with each other then its a pass. We don't measure brightness or angle so that's not an issue.

Do I take it that you are an MOT tester ?

If so, imagine this scenario -
You are testing a tail light that is incredibly dim and dark to the point that your eyebrows are raised and you think about failing it as it could be dangerous - I am not questioning your decision, nor powers to do this, if you think this is a safety fail, then rightly so -

However, if the owner of the car disagrees and says, "Oh no it isn`t" - where do you go from there ?

what guidelines / information / powers that be, have the final definative say on this, as I`m really struggling to satisfy my curiosity on this now.

 :-?

Yes I am a tester. At the end of the day it is down to the tester but if it was that dim you were struggling to see it then its a fail (it must be visible from a reasonable distance ). If in any doubt then then we should pass and advise. I tend to go about 20 meters away and see if I can see them.
As a tester we have to follow the manual  http://www.transportoffice.gov.uk/crt/doitonline/bl/mottestingmanualsandguides/mottestingmanualsandguides.htm .
As for who makes the final decision that would be the tester if the owner disagrees then they can put in an appeal to vosa and see the outcome(either win or lose if they win the appeal the tester gets sent for retraining and or a bollicking. If they lose then they're £50 odd down and still have to fix it

[Dave DND]

lee4206 , 
Thank you for confirming my suspicions - That was exactly the reply I was hoping for from an MOT tester, and its refreshing to know that you guys have an element of discretion -

I have read the MOT "Bible" and couldn`t find anything in there either, and as yet, I do not feel that VOSA have any definative rules and regulations regarding this.

So as long as common sense is used when converting the lights, and the MOT tester is happy, then all should be well (for the time being anyway)

 

[Martian]

Having an MOT doesn't mean you are compliant with the C&U regs, though.

Spot on 

The number plate on my bike is not even close to road legal due to it's size, but it passes every year as the tester claims to have "above average eyesight" and says he can read it from the required distance 


@ Dave,

Why not just go for the LED lamps that are "standard" replacements for the filament jobbies?

[aaronjb]

@ Dave,

Why not just go for the LED lamps that are "standard" replacements for the filament jobbies?

I think Dave covered that in the opening post

Before you ask why not use the off the shelf LED conversion bulbs, well, its a fair question, but if you have ever tried some of those bulbs behind Classic Car lenses, you would have answered your own question.

They are pityfull - and in my mind bloody dangerous as they are often so dim.

The replacement stop / tail bulbs generally have a maximum of 24 or 36 leds, 30% of which don`t even point outwards, and the variation between tail and brake is not that good. On tail, there are usually only 9 bulbs running at 75% intensity, and when used behind a smoked lens can hardly be seen at all. From research I have done so far, Motorcycle plastics and modern plastics of lights lens`s seem to be a little thinner and allow light to pass through much more readily, wheras some of the older classic car lens are so thick, that even a filament bulb can often appear dim.

I tried fitting an LED replacement on one side and a 10 Watt bulb on the other and there was no difference - (I have tried both red and white LED bulbs for comparison) and surprisingly, the red bulb gave a slightly better light behind a red lens than the white one, but still wasn`t great.

[Martian]

I think Dave covered that in the opening post

Doh!
Speed reading and chemo/radio just don't go together 

[Dave DND]

 

 I keep getting into trouble by speed reading as well

 

 

[2woody]

the only guidelines are regarding the percentage of bulbs that must work before a unit is deemed to have failed and requires replacement.

I wrote that bit - under a contract placed by the MoD DfT representative. To quote "At least 50% of the individual LEDs in the cluster must remain working"

Yes, it's almost exactly like the HiD scenario.....

In the UK, there's the lighting Regs, which as you say don't have a requirement for either wattage or intensity. ( Schedule 10, items 8 & 9 ) These are all you need as the owner of the vehicle to be allowed on the road - they do also include viewing angles.

Going one step further, as the manufacturer of the vehicle or the first registerer of the vehicle you must meet either type approval or IVA/SVA, which would require you to have an approved lamp. BUT you're not in that position, 'cos your just an owner making a change to his vehicle.

You're right - the lighting regs haven't caught up with LEDs yet.

I am sure of one thing though - if you ask VOSA, they'll tell you that the lamps must be "approved", just like they've erroneously done in the HiD case.

call me if you need any other advice

[Dave DND]

the only guidelines are regarding the percentage of bulbs that must work before a unit is deemed to have failed and requires replacement.

I wrote that bit - under a contract placed by the MoD DfT representative. To quote "At least 50% of the individual LEDs in the cluster must remain working"

Yes, it's almost exactly like the HiD scenario.....

In the UK, there's the lighting Regs, which as you say don't have a requirement for either wattage or intensity. ( Schedule 10, items 8 & 9 ) These are all you need as the owner of the vehicle to be allowed on the road - they do also include viewing angles.

Going one step further, as the manufacturer of the vehicle or the first registerer of the vehicle you must meet either type approval or IVA/SVA, which would require you to have an approved lamp. BUT you're not in that position, 'cos your just an owner making a change to his vehicle.

You're right - the lighting regs haven't caught up with LEDs yet.

I am sure of one thing though - if you ask VOSA, they'll tell you that the lamps must be "approved", just like they've erroneously done in the HiD case.

call me if you need any other advice

Brilliant !  (No pun intended!)   

Thanks for the extra clarification.

 

[2woody]

nee bother 

[manc-miggy]

A lot of manufactures are using leds for rear lights well side and brake anyway due to the points raised here leds are brighter and cost less and last longer and you can have better styled lights also a few years back a company called ultra brought out led rear lights for the chavs favorite the saxo and I think its audi who have bright white running lights just my ideas on the subject leds are the best though imo