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 quality, but does this matter in reality?


TIA,

David.

In article ,
Dave N wrote:
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 quality, but does this matter in reality?

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.

--
*Lawyers believe a man is innocent until proven broke.

Dave Plowman London SW
To e-mail, change noise into sound.

I'd ask why?

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

--
From the Sofa of Brian Gaff Reply address is active
wrote in message
...
I'd ask why?

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.

On 25/03/2013 14:29, dave wrote:
On Mon, 25 Mar 2013 14:19:52 -0000, "Brian Gaff"
wrote:

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?

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.

The fl.fitting in our kitchen is
30 years old :-)

Yours and all the others!


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

In article ,
wrote:
I'd ask why?

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.

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.

--
*My luck is so bad that if I bought a cemetery, people would stop dying.

Dave Plowman London SW
To e-mail, change noise into sound.

On 25/03/2013 14:29, dave wrote:
On Mon, 25 Mar 2013 14:19:52 -0000, "Brian Gaff"
wrote:

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 :-)



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.

On 25/03/2013 16:11, Dave Plowman (News) wrote:
You'd also have to be careful if changing to LED - some drivers for these
cause flicker too.

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:

Has anyone here had experience with using LED replacements for fluorescent
tubes?

No experience in a domestic environment but seeing them more and more
often in commercial premises, airports, hotels, etc.

What's the light quality from them like?

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.

In particular, I notice the light
output seems to be directional

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.

--
(\_/)
(='.'=)
(")_(")

On Tue, 26 Mar 2013 05:57:04 +0000, Mike Tomlinson wrote:

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.

No.
--
Peter.
The gods will stay away
whilst religions hold sway

In article ,
Mike Tomlinson wrote:
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.

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.

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.

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.

--
*Why isn't 11 pronounced onety one? *

Dave Plowman London SW
To e-mail, change noise into sound.

In article , Dave Plowman (News) wrote:
In article ,
wrote:
I'd ask why?

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.

That is likely caused by flicker. Changing to electronic ballasts sorts
this as they run at a much higher frequency than mains.

Though http://en.wikipedia.org/wiki/Fluores...licker_Effects
says there's also a perceived flicker effect that affects some people as a
result of the spiked spectral pattern of the light output, even when using
high frequency ballasts.

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).)

In article , Dave Plowman (News) wrote:
In article ,
Mike Tomlinson wrote:
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.

That depends on the colour temperature of the HID units.

There are also "xenon" headlights that aren't HID, but supposedly whiter
than halogen:
http://www.autobulbsdirect.co.uk/Xenon-Bulbs.html
http://www.autoexpress.co.uk/car-mai...g-xenon-ultima
http://reviews.ebay.co.uk/Xenon-bulb...00000000088042

On 26/03/2013 17:44, Alan Braggins wrote:
In article , Dave Plowman (News) wrote:
In article ,
Mike Tomlinson wrote:
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.

That depends on the colour temperature of the HID units.

There are also "xenon" headlights that aren't HID, but supposedly whiter
than halogen:
http://www.autobulbsdirect.co.uk/Xenon-Bulbs.html
http://www.autoexpress.co.uk/car-mai...g-xenon-ultima
http://reviews.ebay.co.uk/Xenon-bulb...00000000088042


What a joke! The first site offers (among others):

H4 OSRAM Night Breaker Plus +90% Limited Edition

Just what you want, limited edition!!!

--
Rod

In article ,
Alan Braggins wrote:
Though
http://en.wikipedia.org/wiki/Fluores...licker_Effects
says there's also a perceived flicker effect that affects some people as
a result of the spiked spectral pattern of the light output, even when
using high frequency ballasts.

I'd guess that would only occur with very high efficiency single phosphor
tubes (horrid white) . Tri-phosphor ones tend to have longer persistence

--
*When cheese gets its picture taken, what does it say? *

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
Alan Braggins wrote:
In article , Dave Plowman (News) wrote:
In article ,
Mike Tomlinson wrote:
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.

That depends on the colour temperature of the HID units.

There are also "xenon" headlights that aren't HID, but supposedly whiter
than halogen:

Which is why I called them High Intensity Discharge. Those trying to sell
snake oil will use any ploy.

--
*If only you'd use your powers for good instead of evil.

Dave Plowman London SW
To e-mail, change noise into sound.

On Tue, 26 Mar 2013 05:57:04 +0000, Mike Tomlinson
wrote:

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.

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.

In article ,
Dave N writes:
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.

Seen lots at exhibitions, and some shop fitouts with them.

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 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.

TIA,
David.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

In article ,
mcp wrote:
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.

Last warm white LEDs I tried had even poorer colour rendering than
'white'. And a rather unpleasant greenish hue. Warm white - to me - means
a bias towards the red end of the spectrum.

--
*I will always cherish the initial misconceptions I had about you

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
(Alan Braggins) writes:

Though http://en.wikipedia.org/wiki/Fluores...licker_Effects
says there's also a perceived flicker effect that affects some people as a
result of the spiked spectral pattern of the light output, even when using
high frequency ballasts.

This is a topic driven far more by folks with an axe to grind than by
science, a combination which doesn't make for quality Wikipedia pages.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On 26 Mar 2013 17:44:31 +0000 (GMT), (Alan
Braggins) wrote:

There are also "xenon" headlights that aren't HID, but supposedly whiter
than halogen:
http://www.autobulbsdirect.co.uk/Xenon-Bulbs.html
http://www.autoexpress.co.uk/car-mai...g-xenon-ultima
http://reviews.ebay.co.uk/Xenon-bulb...00000000088042

I've been using Osram Silverstar for years and they actually do what's
claimed. Not sure about the blue-tinted ********, though. Mostly
bull****, I would suspect.

Thanks to everyone for their advice. In the end I've put up some new fluorescent fittings with high frequency ballasts and everyone who's seen them so far admits they can't notice any flicker. Can always bypass the ballast and retrofit LED tubes later.

David.