LED lighting

[ppppenguin]

I'll start by being controversial. Except for specialist applications:

Filament bulbs are dead
Compact fluorescents are dead
Conventional fluorescents are almost dead

LEDs will rule the future of lighting.

For new commercial and industrial installations there is no real argument. Except for some specialist uses LEDs win hands down on cost of ownership. As an example panels like this are now routinely used for shop and office lighting. I have one over my lab bench. Also widely used for refits. Lower enrgy and re-lamping costs win over a very short timescale.
https://www.tlc-direct.co.uk/Products/LTSP50WW.html

For new domestic installations I think we'll be moving to integrated LED fittings without replaceable bulbs.

Who'd want to use CFLs when you can use LEDs? Full stop. I can't even think of an application where CFLs would now be preferred.

Filament bulbs are still needed for high temperature environments. Dimmability is still better than any other technology at the moment. We still need them for lamp limiters

Car headlamps are going over to LED. Surely better than the complexities of Xenon arc. All other car applications should have already moved to LED.

I have used this product and its slightly cheaper non-dimmable equivalent. Nearest thing to a true 100W GLS repalcement.
http://www.diy.com/departments/diall-bay...323_BQ.prd

I have a room with 2 identical ceiling light fittings. I put one of these 15W LEDs in one, 100W GLS in the other. Neither I nor a friend could say which was which. The friend was asked without knowing which was which. the 1520lm output may be overclaiming a little - a 100W GLS gives about 1320 lm. Can't say anything about longevity yet. The dimmable version doesn't dim very well on an ordinary dimmer. Might be better with a trailing edge dimmer. I've seen fairly similar 1520lm bulbs under Philips and Homebase own brand. They seem to be good but I've not used them in my own house yet.

There's a lot of overclaiming with LEDs, just as there was with CFLs. This is especially true with GU10 downlights. A decent 50W halogen GU10 gives 300-350lm. Some are claiming 50W equivalence with 200lm glow worms. A 12V MR16 halogen gives over 500lm, possibly up to 600lm. Not many LEDs will do this. Replacing MR16 with LEDs is a problem due to minimum loading requirements of many electronic transformers. These look good: http://www.toolstation.com/shop/Lighting...mp+/p65928 Another problem with GU10 and MR16 is spread of light. A lot of LEDs give uneven light or over a narrow cone. The decent ones are OK but the problem is knowing which ones are decent.

Colour rendering? Most LEDs have a CRI of 85-ish. Not perfect but good enough for most purposes. There maybe specialist colour matching LEDs, just as there are specialist colour matching fluorescents. Filament bulbs have a CRI of 100 by definition though the colour tempeature may be too low for some applications.

All comments welcome.

[Mark Hennessy]

I agree that LEDs are finally coming of age.

We have some fittings at work which were put in about 3-4 years back, and they are terrible. Just awful. But the new panels are impressive. Once my stocks of T5 tubes start to run low, I plan to fit several in my cellar (where head-height is a serious problem) - the 300mm wide variety should fit nicely between the joists and give a nice, diffuse spread of light. Of all the problems of a low ceiling, lighting is perhaps one of the harder ones to overcome (perhaps surprisingly).

The early units had 2 problems - far too blue, and unreliable electronics. The former seems to be better - although I wonder if the yellow phosphor will gradually lose output, just like it does in CRTs and VFDs, resulting in a blue shift over time. But the great unknown with any fitting - irrespective of manufacturer or price - is the quality of the electronics. I suspect the LED will outlast the driver in most cases. Similar, of course, to CFLs and many HF ballasts...

A related issue is the drive strategy. A HF buck converter supplying a constant DC current is obviously the way to do it (and I assume these are/will be available with 1-10V dimming, like HF ballasts?). But many simply use capacitor-dropper supplies from the mains, so flicker at 50 or 100Hz. Many people are sensitive to flicker, though they might not realise, and I wonder if some of the (usually irrational) arguments against LED lighting is because of that.

Of course, switched-mode power supplies can cause interference, but there's so much of that around these days that I doubt that LED lighting will make a huge impact to most of us who live in built up areas. Though if you've bought an isolated place in the wilds for some serious DXing, that might be different...

I suspect that white using RGB LEDs might be a premium option for the future. Obviously, colour-changing fittings exist, but RGB should give a better CRI than B+Y phosphor.

In TV, RGB LEDs are now commonplace. They result in a massive saving in energy costs (not just in consumption, but also shifting the heat elsewhere), but capitol costs are still very high. They usually come with DMX control, but 0-10V is also common. Of course, LED backlights in LCD panels are ubiquitous today - though quite a bit of work is needed to ensure a good spectral output. My cheap LCD in the workshop has poor reds compared to my expensive Dell, or the earlier CFL version of the same monitor that I have on my desk at work. Against that, the CFL version takes about a minute to reach full brightness, and I wonder how long the tubes will last, given that recently I had to put the brightness level up by about 20% to reach my preferred level (sad, I know, but I use a Philips PM5639 colour analyser to line up my monitors and TV sets!).

CFLs - like plasma TVs - were only ever a stop-gap. They served a purpose, and the handful that we have here are fine for what they do.

[Murphyv310]

Hi.
My 15 year old Rover 75 has a high percentage of LED illumination, British car with some German input but at the time the highest level of technology we take for granted these days.
I have been an advocate of LED lamps for well over 10 years, things have really moved on recently, CFL's must have been the worst things ever and the research should have gone to LED technology rather than those horrible CFL's.

[Joe]

Here, hear, Trevor.

— Joe

[peter scott]

I have experimented with quite a few 50w MR16 replacements and would mirror Jeffrey's comments about optimistic lumen specs, reduced cone spread and less than perfect colour content. We have two rows of three in our kitchen ceiling but I felt I couldn't get away with replacing more than half with LEDs.

Peter

[Raditechman]

I have mainly LED lighting now. I also bought an LED  light panel, nice and bright, and a slim fitting too.
Most of mine are white and not warm white, I switch over to warm white only at late evening before bedtime.
In one of the  opinionated newspapers last week I had to chuckle as a journalist had written that according to her a reason for a Brexit was that we would be able to buy ordinary filament lamps again! they get funny ideas.
I know what lamps I prefer.
A large supermarket near me is all LED lighting, as are some multi storey car parks.
I have seen a church hall where 8ft florescent tubes have been replaced with 8ft LED tubes.
My local council has changed all the street lamps  to LED.
I also have a holiday home in Spain, and the streetlights there are now LED.
I only wonder with the longevity of LED lamps how much light output will be lost as they will get dirty/dusty if in situ for many years.
With the older technology the lamp would get changed and the fitting have a wipe over.
Perhaps in the future a ceiling of a room will be one big light panel.
John

[Radio Fixer]

Still a fan of long fluorescent tubes over work benches though. In my garage I have several and they cost nothing as they were rescued from skips. Maybe a new tube after a while.

Gary

[ppppenguin]

My main objection to conventional florries is flicker. Not the starting flicker but the continuous 100Hz flicker which is annoying in peripheral vision. It's hazardous if there's rotating machinery as it can act like a strobe light. Past solutions were lead-lag fittings with 2 tubes and 3 phase fittings with 3 tubes.

Then came HF ballasted fittings which are quite nice. I have a couple. But these are now obsolete due to the rise of the mighty LED. You can retrofit conventional florries with LED tubes. Still more expensive than conventional tubes but not extortionate.

http://www.premierltg.com/should-you-rep...d-tubes-2/
http://www.screwfix.com/c/electrical-lig...nology=led

Reduced power consumption, reduced or zero flicker.

[Radio Fixer]

Didn't know about a direct replacement so thanks for that. Wont buy any more of the old tubes then.

Gary

[ppppenguin]

Impressive catalogue of LED lighting products. Enlite is part of the well known Aurora company.
http://enlitelighting.com/Documents/Enli...K-web.aspx

Example of Enlite product at Toolstation. This is a good looking dropin replacement for a 50W 12V halogen. Though watch the MINIMUM power rating of the transformer. Many electronic transformers have a 20W minimum load. Should be OK if you can run 4 of these 5W LEDs from them.
http://www.toolstation.com/shop/Lighting...mp+/p79583