LED lighting concerns

Ediswan · 29 Jan 2018

Aussie_Rail said:
LED lights are also used on trains as marker lights, don't have any issues with those.

The one time I saw Tornado, it arrived with LED lights. Looked a bit odd, but I can understand why it is done.

Bletchleyite said:
Most excessively bright headlamps are tungsten xenon.

Congratulations on being one of the very few people who bother to distinguish between those and xenon discharge. Very different devices. The term 'Xenon headlights' is infuriatingly ambiguous.

bramling said:
Also I'm sure LED bulbs dim as they age.

They do, as do most (all?) other lamp types. Anybody interesting in knowing more should look up "lumen maintenance".

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cjmillsnun · 29 Jan 2018

najaB said:
Again, a vanishingly small numbers of cars have LED headlights. The vast majority of 'dazzling white headlights' are Xenon-halogen. LED headlights aren't (for the most part) even legal in the UK.

Tungsten Halogen are not too dazzling at all, even Tungsten Xenon.

Xenon (HID) are a bit dazzling, but LED as used in the latest MINI are bloody awful. They aren't that uncommon now. I encounter them daily.

EssexGonzo · 30 Jan 2018

Actually, It tends to be poor adjustment of car headlamps, rather than the specific light source, that causes the dazzle. Just as many yellowy halogen lights are poorly adjusted as xenon and LED lights. Some manufacturers make the cut off point too close to uncomfortable.

And a headlamp's legality is nothing to do with the type of light source - a candle could still be used it it were practical and effective. The regs are based on position, beam pattern and height, brightness and operation. For example, cars with a dipped headlamp exceeding 2,000 lumens must have self levelling capability (either car or lamp) plus washers to avoid dazzle. What you're seeing more of is aftermarket conversions that seek to ape what was once a premium option but without these fittings - technically illegal but not often enforced.

najaB · 30 Jan 2018

EssexGonzo said:
And a headlamp's legality is nothing to do with the type of light source - a candle could still be used it it were practical and effective.

That's not what I've been told, and not what I've read elsewhere. E.g. How to fit LED lighting to your car legally.

aar0 · 30 Jan 2018

Most LEDs on the front of a car annoying you will be DRLs, Daytime Running Lights, unfocused and on permanently. I'm not a fan, driving as I do a very low car.

Ediswan · 31 Jan 2018

EssexGonzo said:
And a headlamp's legality is nothing to do with the type of light source - a candle could still be used it it were practical and effective. The regs are based on position, beam pattern and height, brightness and operation.

najaB said:
That's not what I've been told, and not what I've read elsewhere. E.g. How to fit LED lighting to your car legally.

I believe the original point was that there is no specfic rule to stop a vehicle being type approved with candles. The hard part would be making that 'practical and effective'. The quoted article is about type approval (or rather lack of) for LED replacement lamps, for use in existing vehicles. If you had a vehicle that was type approved with candles, you would have to use candles that were themselves type approved.

3141 · 31 Jan 2018

tom1649 said:
Indeed, you can now get 2700k LED lamps that give out warm white light that's just as good as the old incandescent lamps. The Osram ones I bought for my flat use LED filament technology and are the exact same size as incandescent lamps of old. LED technology has come a long way over the last few years, just a shame that cool white is often used where warm white would be more suitable.

Sounds as if you and I have much the same lamps. Interestingly, we've two identical fittings in the living room and the ones with Osram LED filament lamps give a slightly yellower light than the ones with spiral compact fluorescent tubes, though all of them say they are 2700K "warm white".

It's great that the Osram lamps are the same size as incandescent lamps. Too many LEDs have been bigger and stick out beyond the end of fittings that were designed for incandescent lamps. Which? magazine has gone overboard in support of LED lamps because they use less energy, and ignores the ppracticalities of finding LEDs that fit within older light fittings.

najaB said:
Sodium lights are fantastic for accountants but terrible for human vision. If you have a large area to provide basic safety lighting then they are perfect, but don't expect people to be able to do anything fancy like being able to distinguish colours. LED lights are perfectly safe, and as others have already posted available in a wide range of colours (and colour temperatures).

I can recall sodium street lights replacing mercury ones in the 1950s. They were said to provide a better illumination, and I think that was true: the light seemed more even and illumined more of the area. I don't think there was any health and safety issue about the mercury lights, because no-one bothered much about mercury in those days. (It was great fun to play with in school science lessons.) In Hampshire most street lights have become LEDs in recent years, accompanied by publicity about how much better they are than sodium, similar to what was said when sodium replaced mercury. The new LED lights certainly don't glare, but they do provide a more natural light than sodium.

najaB · 31 Jan 2018

3141 said:
I can recall sodium street lights replacing mercury ones in the 1950s. They were said to provide a better illumination, and I think that was true: the light seemed more even and illumined more of the area.

It was more even and did light a larger area. However they are terrible for colour discrimination - it's not a frequency that the eye is particularly good at seeing.

Ediswan · 1 Feb 2018

najaB said:
However they are terrible for colour discrimination - it's not a frequency that the eye is particularly good at seeing.

They (low pressure sodium lamps) are essentially monchromatic, two lines at 588.9950 and 589.5924 nanometers. That is why they are terrible for colour discrimination. Even bright low pressure sodium lighting shows no colour. For colour discrimination, you need more wavelengths (this quickly gets very complicated). I probably should mention I once worked in a lamp research laboratory.

Jonny · 1 Feb 2018

I also find that blue-y LEDs are good for when I am doing something in the evening and want to keep awake for a few more hours.

krus_aragon · 1 Feb 2018

najaB said:
That's not what I've been told, and not what I've read elsewhere. E.g. How to fit LED lighting to your car legally.

Similarly, until a 2005 revision of the law, LED lighting was not road-legal for bicycles: only incandescent bulbs conforming to BS6012 (I think) were permitted. I think you could technically use a flashing LED light, but you'd have to use an incandescent as well.

By this time, it was already clear that the brighter light, reduced power usage and attention-grabbing flash of an LED light was a far better option for cyclists, and LED lights were in relatively common use on bicycles. The law was behind the times, and eventually updated. (Now "flashing lights emitting light of a brightness of at least X candela" or similar is included as an option in law.)

Bletchleyite · 2 Feb 2018

I do wish they would add "with a pulse frequency of no less than 100Hz, or no more than 5Hz"[1], though. I find the flicker from cheap-rubbish aftermarket LED tail lights hugely distracting.

[1] The latter is needed so as not to inadvertently make flashing bike lights illegal, as they are highly effective.

jon0844 · 2 Feb 2018

najaB said:
Again, a vanishingly small numbers of cars have LED headlights. The vast majority of 'dazzling white headlights' are Xenon-halogen. LED headlights aren't (for the most part) even legal in the UK.

Lots of vehicles now have LED lighting for dripped and full beam, with some clever ones even able to adapt the light spread as you go.

Very much legal and arguably without the glare at the 'edges' that you get with Xenon lamps.

Xenon lamps gradually age and the colour temperature changes and now I see a lot of cars with more green/yellow lights than white. LEDs should at least remain constant.

As a side rant, I do hate the manufacturers that forget the importance of lights and that they're not just additional design features. Headlights with embedded indicators you can't see because the white is too overpowering, or now cars that alternate between white and yellow when indicating (a bit like American cars used to have brake lights flashing for indicators).

I'm all for clever designs but make it so you can actually tell a car is indicating and keep the main lights on at each side of the car...

bramling said:
I'm sure LED bulbs dim as they age.

Yes, but they shouldn't do so until after their advertised life - and even then only fairly gradually. You're bound to have got rid of the bulb before it's an issue, or it will have failed because the circuitry/heat sink or some other component fails (and then, depending on who made it and where you got it, and if they're still in business, you may well be entitled to a replacement FOC).

najaB · 2 Feb 2018

jon0844 said:
Lots of vehicles now have LED lighting for dripped and full beam

Of the total number of vehicles on the road it's got to be well under 1% just because of the huge number of cars already out there.

whhistle · 2 Feb 2018

I think the problem is that the council people haven't adjusted the brightness, assuming it's just a bulb replacement that is required.

I replaced nearly all the lights in my house with LED. Most are warm white. Two in the model railway room are panel lights and not too harsh, despite being the bright white colour.

However, the cheaper "candle" bulbs I got from Screwfix do have a flickering that I can see. Makes moving something like a tea towel around look a little strange.

Yet the cheap "normal" looking bulbs don't flicker.
Still debating whether I should take [the candle] ones back as they have a guarantee anyway and I saved the packaging after reading some of the reviews on their website.

Unless I'm in some restaurant that's styled for the old yellow colour bulbs, I don't like them at all.

Bletchleyite · 2 Feb 2018

whhistle said:
I think the problem is that the council people haven't adjusted the brightness, assuming it's just a bulb replacement that is required.

They are mostly replacements of the entire lamp head (in some cases the whole thing, standard included) with a permanent LED fitting rather than an LED bulb.

eMeS · 3 Feb 2018

In Milton Keynes I note that several "city" roads are now completely without street lamps after dark. 100m further on, and the old street lamps are now lit using LEDs. It seems as though the LA is only allowing street lamps where they decide that pedestrians are likely to cross the road. In time, I expect the new policy will lead to more road accidents at night.

As an aside, I've got a hobby interest in precision measurement, slip gauges/gauge blocks and similar, and the use of optical flats for checking their surface flatness etc. Trying to find an affordable monochromatic light source for use with the optical flats was impossible, so I made my own using a discarded low pressure sodium street lamp as the source. Cost me around 1/20 of the listed price, and several LP sodium lamps were included as a bonus.

jon0844 · 3 Feb 2018

najaB said:
Of the total number of vehicles on the road it's got to be well under 1% just because of the huge number of cars already out there.

Well yes, but the change will probably end up being quite rapid as it has with cars now having daytime running lights (wasn't it all cars built from 2011 or something, although there can be exclusions on older cars registered afterwards).

Give it 5 years or so and I'd say that most new cars will have LED headlamps, or at least anything but the base models. It's something car makers like to advertise, just as they did with satnav and Bluetooth and other features that people will come to expect.

jon0844 · 3 Feb 2018

Bletchleyite said:
They are mostly replacements of the entire lamp head (in some cases the whole thing, standard included) with a permanent LED fitting rather than an LED bulb.

I've never seen a street light that has had a LED bulb retrofitted (but of course there may be some). They are nearly always a brand new fitting, and many of them are quite intelligent.

They can be controlled remotely, and be set to offer different brightness levels at different times of the day. I think they can also be operated as a mesh network and could potentially provide Wi-Fi or 5G connectivity in the future, if councils could make a business case.

The reduced light pollution is another plus, given the reduced glare. They are very directional and that's why they are pretty good for street lighting and on vehicles. That's not to say you won't find badly designed or fitted examples to blow that theory.

Hertfordshire County Council has got many lights turning off at midnight until around 0600 or 0630. It would seem that they operate at full brightness from dusk to switch off, then in a dimmed state on some roads in the morning.

It would seem logical to have some lights (say one in two or three) in a dimmed state all night, as that can provide enough light to see where you're going because your eyes will adjust (and there's no glare) but councils don't seem to have been that clever. Yet they then leave whole roads with the lights on all night, at full brightness.

I know there are A, B, C roads and so on - but there's often little logic as roads mostly used by cars are lit, those more likely used by people on foot are dark.

R G NOW. · 14 Aug 2019

aformeruser said:
The LED street lights my council have installed (primarily to save money) actually seem slightly dimmer than the old ones they replaced and I know someone who's had cataract surgery who says they are an improvement over the old ones as they produce less glare. However, the LED traffic lights seem very bright in the dark and due to complaints from nearby residents some pelican crossings (with flashing amber) have been replaced by puffin crossings (which have no flashing amber.)

Always thought traffic lights always dimmed at night. usually switched by a photocell on one of the posts.

R G NOW. · 14 Aug 2019

The street lights outside my flat dim a bit at midnight, overwise they are too bright. Why didn't lantern makers think of putting a diffused bowl on them, this would dim the light a bit but would be kinder to the eyes. Like some lights now in shops, where they have led panels in suspended ceilings, but have a misted panel underneath.

edwin_m · 14 Aug 2019

R G NOW. said:
The street lights outside my flat dim a bit at midnight, overwise they are too bright. Why didn't lantern makers think of putting a diffused bowl on them, this would dim the light a bit but would be kinder to the eyes. Like some lights now in shops, where they have led panels in suspended ceilings, but have a misted panel underneath.

A diffuser blocks some of the light completely, so reduces efficiency. It also diffuses the light more widely, again reducing the effective efficiency (light where it is wanted versus power in) and contributes to light pollution. I wonder if there should be some kind of "waffle baffle"* with slats in between each LED so no light at all can escape sideways outside the required cone of illumination. Then they would only be dazzling if looking upwards towards one, not along at one from a distance.

* a good description of some of the stuff on this forum?

R G NOW. · 14 Aug 2019

edwin_m said:
A diffuser blocks some of the light completely, so reduces efficiency. It also diffuses the light more widely, again reducing the effective efficiency (light where it is wanted versus power in) and contributes to light pollution. I wonder if there should be some kind of "waffle baffle"* with slats in between each LED so no light at all can escape sideways outside the required cone of illumination. Then they would only be dazzling if looking upwards towards one, not along at one from a distance.

* a good description of some of the stuff on this forum?

Are you thinking about the batwing reflectors, that used to appear in office and shop lights, when all we had were fluorescent tubes then. Your suggestion would be a better one to prevent dazzle to people walking or driving.

AM9 · 14 Aug 2019

goblinuser said:
They are legal and car manufacturers are using them. However, if the lamp breaks the entire headlamp or tail lamp cluster needs to be replaced in one unit.

That's not necessarily true. LED headlamp units that replace the bulb have been fitted increasingly in cars for at least 3 years. They tend to be of the fan cooled type with three terminals. With the introduction of EVs, they will soon become almost universal as their unit cost plummets. They also have better beam shaping than most incandescent or plasma lamps. After market H4 or H7 shaped replacements aren't generally legal on the public highway.

AndrewE · 14 Aug 2019

Ediswan said:
The only light sources which emit UV are those which are intended to. Filtering out UV within the lamp is straightforward. (Properly made of course.)

Wrong. Metal halide lamps emit loads of UV because they are in quartz envelopes because of the temperature and pressure of the gas inside. I investigated a serious case of arc-eye and skin irritation which turned out to be the result of decorators working around them before the secondary pyrex glass UV filters were installed. Some cars were fitted with them too, I think the manufacturers claimed that the UV output helped drivers see further in fog, or some such crap.
High up in the roof of a warehouse they might be a good idea, anywhere near people they are definitely not.

EssexGonzo · 15 Aug 2019

jon0844 said:
Lots of vehicles now have LED lighting for dripped and full beam, with some clever ones even able to adapt the light spread as you go.

Very much legal and arguably without the glare at the 'edges' that you get with Xenon lamps.

Xenon lamps gradually age and the colour temperature changes and now I see a lot of cars with more green/yellow lights than white. LEDs should at least remain constant.

As a side rant, I do hate the manufacturers that forget the importance of lights and that they're not just additional design features. Headlights with embedded indicators you can't see because the white is too overpowering, or now cars that alternate between white and yellow when indicating (a bit like American cars used to have brake lights flashing for indicators).

I'm all for clever designs but make it so you can actually tell a car is indicating and keep the main lights on at each side of the car...

Agree with a lot of this. There are some cars where the indicator is now so invisible against a white LED DRL or headlight bulb (e.g last version of the Qashqai) that I've had a couple of near misses with that model.

But in general, I find LED headlights less glaring and uncomfortable than Xenon/HID lamps. Mostly, the glare isn't there but also, manufacturers have produced versions with lower lumen ratings for cheaper cars (but still with the "kudos" of LEDs instead of halogens) where they couldn't for HIDs. This avoids the need for washers and self-levelling but has the happy side benefit of not being as dazzling.

From a driving perspective, they're also more comfortable with the light temperature being more akin to daylight than the yellow glow we've been used to.

AndrewE · 15 Aug 2019

AM9 said:
That's not necessarily true. LED headlamp units that replace the bulb have been fitted increasingly in cars for at least 3 years. They tend to be of the fan cooled type with three terminals. With the introduction of EVs, they will soon become almost universal as their unit cost plummets. They also have better beam shaping than most incandescent or plasma lamps.

What are plasma lamps, please? Googling doesn't help.

whhistle · 15 Aug 2019

Whereas I went to a garden centre the other day. As I visited the toilets, I thought it was a window, but alas just a bright daylight LED light.
I was a little impressed though, quite powerful but not stupidly bright.

LED lighting concerns

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