Has anyone here had experience with using LED replacements for fluorescent tubes? They're becoming affordable (1200mm T8 tubes from about £20) and I was thinking of using LED tubes in a standard dual batten lampholder with polycarbonate diffuser fitted, with the ballast circuit bypassed.
What's the light quality from them like? In particular, I notice the light output seems to be directional, which will no doubt affect the light quali ty, but does this matter in reality?
TIA,
David.
I'd ask why?
Fluorescents have an extremely long life using well proven technology, are very efficient using decent electronic ballasts, and have a wide variety of colour temperature tubes - at least in the common sizes. And give an even light over their entire length.
There's a particular reason why - the lighting is for a room for use by disabled people, some of whom have indicated an intolerance of fluorescent lighting. We're trying to offer an economical alternative.
Are we talking visually impaired here? I think you need to be extra careful, as some of the led units have a far worse flicker than normal tubes, and in some cases the colour temperature is so lumpy in the visible spectrum that many VIPs complain of the light being grainy and causing poor contrast. Far better I think to use a good make of electronic ballast with conventional tubes then get specific task lighting in for those who need it. Brian
How does one know the quailty of the elctronic ballast? If I buy a fl.tube light from say B&Q is the fact it is "modern" some assurance it is better than much older designs? The fl.fitting in our kitchen is
30 years old :-)
No, and in fact unless it explicitly states it contains an electronic ballast, there is a fair chance it doesn't... You can buy them separately for retrofitting though.
Yours and all the others!
That is likely caused by flicker. Changing to electronic ballasts sorts this as they run at a much higher frequency than mains.
You'd also have to be careful if changing to LED - some drivers for these cause flicker too.
When I was in B&Q a few weeks ago they only had one slimline fitting with electronic ballast, all the others were "old fashioned" ballasts.
I've seen LED spots with far worse flicker than any healthy fluorescent. I think they may have been strobing at 50Hz with a short on, long off pattern.
Andy
En el artículo , Dave N escribió:
No experience in a domestic environment but seeing them more and more often in commercial premises, airports, hotels, etc.
It's very white, makes halogen look yellowish. Similar to comparing xenon headlights with incandescent on cars - you think incandescent are white until you see both together, e.g. on the motorway.
As others have said, the spectrum isn't wonderful. In a hotel room lit by LED light recently I thought the light quality was very good - close enough to halogen for me to have a squint at the fitting to see what was there - but when I took out my vitamin C tablets, which are bright orange in natural light, they were very washed out under LED light.
It made me think that some interestingly-coloured food could come out of kitchens lit by LED.
LEDs are directional by nature. A diffuser, as you mentioned, will definitely help to, um, diffuse the light.
Recently I saw some fittings which has been retro-fitted with LED. They were the sort that had metal reflectors above the tube to direct light downward, and no diffuser. LED light is very harsh and not pleasant to look at directly. The tubes had been fitted with the LEDs pointing down; I'd wondered if it would have been better to install them pointing up, so that he light was scattered off the reflector, indirect lighting in other words.
Finally, all the LED tubes I've seen have been clear plastic. Wondering if using opaque material would cause them to emit a more even light.
That depends on the colour temperature of the HID units. Some now have CT close to halogen. Of course with those you may think they are halogen.
Quite. It is rather obviously proving difficult to provide a continuous spectrum LED at a sensible price while retaining efficiency. This may not matter to some - but I'd find it very annoying for domestic use.
Translucent material might.
Owain
Though
But changing to LEDs won't necessarily help with that. (And as other people have said, whether it will help with 100Hz flicker depends on the drivers (and, as with fluorescent, the phosphor used).)
There are also "xenon" headlights that aren't HID, but supposedly whiter than halogen:
What a joke! The first site offers (among others):
H4 OSRAM Night Breaker Plus +90% Limited Edition
Just what you want, limited edition!!!
I'd guess that would only occur with very high efficiency single phosphor tubes (horrid white) . Tri-phosphor ones tend to have longer persistence
Which is why I called them High Intensity Discharge. Those trying to sell snake oil will use any ploy.
They are actually blue LEDs with a bit of white phosphor on the end. The more phosphor you put in you get the less of the blue and the more white it looks but they get dimmer. A warm white would give nore natural colours than a cool one.
tubes? They're becoming affordable (1200mm T8 tubes from about £20) and I was thinking of using LED tubes in a standard dual batten lampholder with polycarbonate diffuser fitted, with the ballast circuit bypassed.
Seen lots at exhibitions, and some shop fitouts with them.
output seems to be directional, which will no doubt affect the light quality, but does this matter in reality?
All the ones I've seen are directional, but in most cases, the light output from fluorescent fittings is directional anyway, and significant light is lost from the far side of the tube, even when reflectors are used. This gets around that to a significant degree.
They tend to be available only in the higher colour temperatures (colder bluer whites), because LED efficiency is significantly higher there. (Same is true for fluorescent lamps, but the difference is much smaller.) This means they will only look right at higher lighting levels. The highest efficiency ones have rows of point source LEDs visible which you might find uncomfortable. However, most include a diffuser, which loses some efficiency.
Colour rendering - I haven't looked specifically at the LED tubes, but LEDs in general are close to the cheaper fluorescent tubes, but that only works if you get the lumen level high enough to match the colour temperature, and that will mean higher light output may be required than your fluorescents might have produced.
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