To be honest Dave, I'm not certain. I'm sure I have seen them on websites where they claim to match the specs for brightness etc, so I've always assumed that any that are deliberately manufactured as 'replacements', would similarly match. However, I accept what you say, and they might not all be. Are the likes of Lucas or Delco or whoever making these things yet ? I guess that would be the best guarantee of compliance. In any event, I should think that ones made for the job, are likely to be better in terms of brightness and viewing angle, than something that you would cobble together yourself ??
FWIW, I don't actually like the latest generation of cars that are fitted with LED tail and brake lights. They are invariably pulse driven, and when your eyes do a 'flick', the pulsed LEDs leave a trail of 'dots' of light across your vision. Most off-putting when driving at night. The roadworks cone lamps are similarly pulsed. and create the same effect.
There are many retrofit lamps on the market which are certainly *not* street legal, and for obvious reason if you see them in action. I don't know if anyone makes any that are, but I would think the technology at least exists.
I don't think there'd be a problem using retrofit lamps for things like license plate illumination and certainly anything inside the car, but I would hesitate to put one in any of the external marker or signal lights.
The link that I posted was not to an eBay listing, which is not to say that they don't sell on eBay, of course. However, they are at least 'up front' about the differences and limitations, and the potential for things like incorrect flasher speed, when you retrofit them. See
Having played around with them many that claim this certainly are not. An ordinary filament bulb gives an approximately 360 degree even light output. The fitting includes a reflector to then direct that light where needed. And this can be important with things like indicators (21 watt) where you want them visible from a wide angle. Those multiple 'ordinary' LED replacements simply don't do this.
I've yet to see any OEM replacements for tungsten. And those would have to be E marked to be legal in the UK etc.
I'm not so sure. One problem seems to be incorporating both the LEDs and drivers - either electronic or simple resistive - within a replacement unit. If you modify things to use an external driver you give greater versatility. Wide angle high power LEDs are available these days to match a 21 watt tungsten.
Another example of fashion before practicality? Power consumption of such things in cars ain't important and LEDs which are bright enough without being pulse driven exist. More expensive, though.
*Shin: a device for finding furniture in the dark *
Dave Plowman email@example.com London SW
There are auto parts stores in the USA that sell "drop-in" replacement led lamps,. Murray's auto parts is one store in the Chicago suburbs that I know my son-in-law has purchased them from (to dangle a preposition).
I bought some boards for my new deck. I have yellow lamps on some of the posts. i put these inside some brass door pulls, look cool. You can wire these up as you like or need. They are designed to replace those little lamps with the two bent wires around the glass end. Many trailer lamps use these for running lamps.
The lights I'm talking about are used in lieu of twin filament incandescent lamps for tail/brake lights. These have two brightness levels, and to achieve that with LEDs they use PWM dimming to give two levels.
I don't think that is an actual requirement though. A LED could just as easily be dimmed by DC current reduction, although I agree, it would less efficient in terms of wasted energy. Some time back, I did a lot of reading on driving LEDs, and the manufacturers seem to advocate pulse drive for two reasons. The first is that very high pulse currents can be used compared to DC drive currents. As the light output is proportional to the current, this means that very high level light pulses can be achieved, without hotting up the die beyond what it can dissipate. The total result of this is a higher average light output for a lower dissipation than would be achieved by DC drive. The second reason is that pulse drive extends the useful 50% life of the LEDs, by as much as 10 times. So I guess both you are right in that it makes them easier to control, and so is Dave in that it makes them brighter ...
They may well but the primary reason is to increase the brightness. Pulsing allows the continuous current rating to be exceeded. And necessary with most common LEDs if you need to near match the output of tungsten for brake lights etc. To alter the brightness on an LED all you need to do is change the drive current. Doing it via PWM is more efficient - but that really doesn't matter with car indicator lamps.
*Can vegetarians eat animal crackers?
Dave Plowman firstname.lastname@example.org London SW
All in all, I feel that pulse drive is terrible for tail lights. As someone else stated they are irritating to the eyes. I can't stand driving behind someone with LED taillights. They make my eyes do weird things and it is not a plesant expirence. I already wear glasses and have some trouble seeing at night, I don't need more trouble from tail lights that are flashing at 30hz. No one else I know can seem to see that they are flashing, but then again I can also tell if my monitor is set at 60 or 85hz just by looking at it. For me the flashing stops at about 85hz.
It was me who said this Mike, and I know what you mean. Nobody else in my family knows what I am talking about when I tell them that I see a trail of light 'dots' across my vision when I look at these things wrongly. There used to be very strict constraints on car designers about where lights could be positioned, and how far apart and such like. Now, there seems to be no such restrictions, and anything goes. Some brake lights, for instance, are blinding, and there's three of 'em ! Makes you wonder if any of this contributes to accidents ...