LED Fluoresecent replacements ????

[Turnip Watch]

" About 24% of the energy used by metal-halide lamps produces light (an efficacy of

65-115 lm/W),[4] "

HTH

TurnipWatch

[dennis]

Have you tried looking with anything that will show strobe effects? A HF converter will strobe as LEDs have a very fast response time, much faster than flouries.

[dennis]

Strobing can be a problem whatever frequency it runs at. Its just that the phosphors don't respond fast enough to be a problem with most HF ballasts.

[dennis]

I don't think harry knows the difference between metal halide lamps and halogen lamps.

[dennis]

is that harry pretending to be a philosopher?

[T i m]

Too true. ;-)

On the subject of different lighting in general ...

It's funny, I think it's pretty well agreed that the old incandescent gave off a fairly 'good' light for all sorts of human related things. This was because when non-'flame' type lights were being invented, that's what they came up with that 1) worked 2) were easy and cheap to make so we have stuck with them (for general use) for a long time. It's only recently with all this eco stuff and with the advent of alternatives becoming cheaper that we are going over to the alternatives, for some situations and 3) because we are forced to to some degree (apart from those who stockpiled incandescent's of course). ;-).

So, in the workshop, kitchen and loft we have fluorescent strip lights because we want good light spread generally. Unless LED lamp replacements can duplicate the light level and (omni)directionality cheaply I can't see those changing here.

In most of the rooms we have a central pendant type light (or light in a fan) with either CFL or LED (often the brightest we can find in 'warm'). In the lounge and bedrooms we also have some sort of side - light(s), again typically 'warm' CFL, LED and one incandescent candle lamp (on a dimmer) in our bedroom.

We have dusk to dawn adaptors in the fittings in the front and rear entrances and they had the lowest rating CFL and now LED we can find as it doesn't matter what the quality of the light is or how bright it isn't (within reason). ;-)

Over the lathe I have an Anglepoise type lamp with an incandescent spot lamp (high thermal inertia so no chance of strobing). Most of our clip-on / repositional type work lights and my magnifier work light are now using LED but some of the cheaper ones have failed (along with cheaper battery powered LED work lamps). They mainly work (being LED) because they give off a fairly good beam type light, are small and don't get hot.

Many of our torches are now LED, mainly because of the increased ruggedness and battery life (most weren't designed for LED and so don't have as nice or adjustable beam as the old incandescent). However, I feel you get better battery life when converting what was an incandescent torch to LED because the batteries were originally specified for a greater load and hence generally bigger (like my 4 x D cell Maglight ). I think some LED_from_new torches, especially the rechargeable ones have smaller batteries, simply because the LEDs draw less power so don't last as long as they could (when there is no particular requirement to be small or light etc).

Back to the LED replacement for fluorescent strip lights ... do they use or need the ballasts that are typically in these fittings or could / should they really be rewired to be straight 230V and so be more efficient?

Cheers, T i m

[Tim Lamb]

In message , "Dave Plowman (News)" writes

In our kitchen, for low ceiling reasons, we have recessed circular fluorescent lamps which take 2 x G23 9W tubes. The light level is not outstanding.

I see you can get LEDs in a G23 tube shape but assume these are not plug in compatible. What would I need to do?

>

[Andy Burns]

For similar low ceiling reasons in a porch, I have a 5" 6W version similar to this ...

it gives a very good spread of light (maybe the linked ones are different, mine is certainly much greater than 120°) I'd imagine the higher wattage versions might suit.

[The Natural Philosopher]

My bad, I thought we were discussing halogens.

Metal halide is the fancy new name for mercury arc..

[Tim Lamb]

They look to have the same ceiling cut out so could do the job.

[Andrew Gabriel]

I'm guessing you've never seen LED tube retrofits, or more likely, failed to realise they were LED tubes. Also, no reflector comes close to the comparative efficiency of directed LEDs.

No. Most dirt settles on the top. In the case of LED tubes, this doesn't matter as all the light comes out of the bottom. In the case of fluorescent tubes, it does matter as you've lost the light from the top which is expected to be reflected back to where it's needed (and a secondary problem that reflectors are almost never cleaned).

[Andrew Gabriel]

Average decay time for a mercury ion to emit a photon is 1/10000 second, so providing you run at > 5kHz, the mercury light output is continuous (and you don't need to restrike the tube every half cycle). Electronic control gear all runs significantly > 5kHz to make the transformer small (usually in the range 20-50kHz).

[T i m]

If dust settles on the top of stuff and a reflector would typically reflect light back down by it's underside, how would it get dirty?

Cheers, T i m

[Andrew Gabriel]

Top half of the tube.

[Andrew Gabriel]

Sometimes they will work just by plugging in, but the fittings will become more efficient if you bypass the existing ballast so the LEDs are directly across the mains. You need to check the instructions which come with your specific LEDs.

You should be able to achieve significantly higher light output from a single-sided G23 LED, even at lower power rating. Hopefully the fittings have some ventilation, as the LEDs will not stand running as hot as the compact fluorescents can.

If the tubes are directly visible, you probably want to find LEDs with a translucent cover, rather than the individual point sources being visible which are painfully bright. (Sadly, a translucent cover will lose you some light output.)

[Tim Lamb]

In message , Andrew Gabriel writes

OK

Hmm... probably not much. They a fitted between ceiling joists with no insulation but the enclosure has no vents AFAIK

The fittings already have translucent covers. I tried clear ones and found we didn't like seeing the tubes.

Might be worth buying a couple to experiment.

>

[Dave Plowman (News)]

If you didn't like seeing florry tubes, you're going to like LEDs even less. They are a smaller area so a great deal brighter.

It's one of the things about LEDs. You look at them directly and they look very bright. But it's the overall light on the work area which is important. Seems obvious - but something many ignore.

[Tim Lamb]

In message , "Dave Plowman (News)" writes

Suggested thermal issues may also kill the idea. The existing covers are opaque so might be OK.

I'm a bit nervous about China sourced technology in a fire risk area. (directly under our bed!)

>

[Tim Streater]

Yes - that's why we didn't put GU10 LEDs in the bathroom ceiling.

[Dave Plowman (News)]

Pretty well everything you can buy may have been made in China. Poorly made Chinese is no worse than poorly made German. I've not mentioned the UK as so little is made here these days. ;-(