Author Topic: LED room lighting (again)  (Read 53150 times)

Cudzoziemiec

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Re: LED room lighting (again)
« Reply #350 on: 16 February, 2021, 10:04:37 pm »
At least they're telling you which they mean! Do they say anything about CFLs too? (See also: paper, card and cardboard.)
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hellymedic

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Re: LED room lighting (again)
« Reply #351 on: 16 February, 2021, 10:12:48 pm »
I'll check.
I know paper & card go into recycling, but not wrapping paper.

ETA
The links on the right side of this page land you back on the same page, which is MOST helpful.
https://www.brent.gov.uk/services-for-residents/recycling-and-waste/household-recycling/from-a-house-or-converted-flat/blue-top-recycling-bin/#

Kim

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Re: LED room lighting (again)
« Reply #352 on: 16 February, 2021, 10:40:48 pm »
Just for the ignorant ones here (that'll be me), what is WEE and WEEE?

It's one of those pesky EU directives that's crippling honest BRITISH businesses by making them responsible for the hazardous waste they produce: https://ec.europa.eu/environment/waste/weee/index_en.htm

hellymedic

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Re: LED room lighting (again)
« Reply #353 on: 16 February, 2021, 10:49:05 pm »
We buy most of our potential WEEE online.
We're car-free.
Brent's Recycling Centre (aka dump) is 6 miles away.
Taking WEEE to a shop that hasn't supplied it seems unfair and they are probably locked down right now anyway.
Asking D to cycle 6 miles with a bulb or two isn't going to happen.
I can get Brent to collect BIG electrical/electronic items.
But small stuff is a problem.

Kim

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Re: LED room lighting (again)
« Reply #354 on: 17 February, 2021, 12:05:47 am »
Yeah, ours tends to kick around the house until such a time as I'm going to the tip for something more substantial.  Even accounting for generating a lot more WEEE than the average household (we have a reputation for being able to repair and/or find a home for unwanted electrickery), its a pain.

Really small stuff (component-level parts, bits of wire, that sort of thing) tends to find its way into the household waste, because I'm not going to start going through bench-sweepings and hoover bags to separate LED legs and solder blobs from carpet fluff and bits of sticky tape.

Feanor

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Re: LED room lighting (again)
« Reply #355 on: 23 November, 2021, 05:45:03 pm »
Following on from another thread where a 50w MR16 Halogen downlighter nearly set my house on fire, I'm looking to replace them with LEDs.
The existing fittings in various rooms are set into holes in the plasterboard, some are 65mm and some are 70mm holes.

What's the general approach to this these days?

1) Retain the existing fittings, and use like-for-like 12v LED lamps.  This might require new transformers / SMPSUs, if the existing ones have a minimum load which the 5w LEDs don't reach.

2) Retain the existing fittings, and use 240v MR16 lamps, ditching the transformers / SMPSUs.

3) Replace the entire fitting with a dedicated LED unit.

My gut reaction is (1), for the following reasons:

- Having the 240v - 12v PSU external means it can have better thermal management than trying to cram it into the tiny space in the lamp itself, leaving only the 12v LED driver in the lamp;

- I'm not sure the existing fittings / connectors are rated for 240v. But then again they were marginal for the current for 50w @ 12v!  I think I'd prefer to run them at 12 v and the 500mA or so a 5w LED will take.

- I don't want to have to re-drill / patch plasterboard for new fittings which will no doubt be different diameters to my existing mix of 65 / 70 mm 'oles.

So general advice?
And any particular brand of 12v 50w equiv LEDs you'd recommend?

Re: LED room lighting (again)
« Reply #356 on: 23 November, 2021, 06:00:54 pm »
Following on from another thread where a 50w MR16 Halogen downlighter nearly set my house on fire, I'm looking to replace them with LEDs.
The existing fittings in various rooms are set into holes in the plasterboard, some are 65mm and some are 70mm holes.

What's the general approach to this these days?

1) Retain the existing fittings, and use like-for-like 12v LED lamps.  This might require new transformers / SMPSUs, if the existing ones have a minimum load which the 5w LEDs don't reach.

2) Retain the existing fittings, and use 240v MR16 lamps, ditching the transformers / SMPSUs.

3) Replace the entire fitting with a dedicated LED unit.

My gut reaction is (1), for the following reasons:

- Having the 240v - 12v PSU external means it can have better thermal management than trying to cram it into the tiny space in the lamp itself, leaving only the 12v LED driver in the lamp;

- I'm not sure the existing fittings / connectors are rated for 240v. But then again they were marginal for the current for 50w @ 12v!  I think I'd prefer to run them at 12 v and the 500mA or so a 5w LED will take.

- I don't want to have to re-drill / patch plasterboard for new fittings which will no doubt be different diameters to my existing mix of 65 / 70 mm 'oles.

So general advice?
And any particular brand of 12v 50w equiv LEDs you'd recommend?

I've just bought and installed half a dozen dedicated LED downlighters from B&Q - brand Luceco £100 for 6. They are fire rated for insulation laid over the top, IP66, dimmable and change colour (warm, neutral, cold white) byt switching. CRI is >85 and they are far better in terms of light output and quality than any of the MR16 or GU10 lamps that I have tried. They need a 75mm cutout, but I think it's worth an hour with a rasp and a bit of dust for the quality if light. Obviously you'll get rid of your transformers too.

These are in my home office (shed) where quality of light is really impoirtant as I spend far too long in there.

Mike

Kim

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Re: LED room lighting (again)
« Reply #357 on: 23 November, 2021, 06:04:33 pm »
Received wisdom seems to be that if you fit LED fixtures, they'll fail in a couple of years and you'll need to replace them (inevitably with something requiring a different size hole, or at least visibly non-matching).  If you fit GU10 or similar fixtures, they'll be flickery shit from the outset, but at least you can change the lamp when it fails.

Feanor

  • It's mostly downhill from here.
Re: LED room lighting (again)
« Reply #358 on: 23 November, 2021, 06:23:52 pm »
But should the existing fixture used with a proper LED PSU not eliminate the flicker?
What would cause the flicker in this scenario that a dedicated LED fixture would not?

Is it that the dedicated fixtures have both the driver and LEDS in a single unit, and drive the LEDs directly with a constant current, but MR16 drop-in replacements take 12v constant voltage, and then have nasty 12v - constant current gubbins in each lamp?

Googling it, I see some PSUs which are 12v 6w specifically for MR16 LEDs.
I'm not sure what they do differently to 12v PSUs used for halogens ( except continue to work at low loads ).
Different chopper frequency?

I'll need to suck it and see, I think.


Re: LED room lighting (again)
« Reply #359 on: 23 November, 2021, 06:35:35 pm »
I'm sure it's about the quality of the driver and the led - driver for nice non-flickery light (not forgetting that some here see/perceive flicker at very high frequency, so smooth DC is better than a lot of switch mode stuff) and led for light quality/CRI. I just haven't found a particularly nice package yet, although I do have one pair of MR16s that don't annoy me as much as the rest.

robgul

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Re: LED room lighting (again)
« Reply #360 on: 23 November, 2021, 07:52:34 pm »
I bought these for our kitchen on the recommendation of my electrician nephew - not much money - from ledbulbs.co.uk 

Aurora Enlite Fixed Fire Rated IP20 Non-Integrated Downlight Satin Nickel- EN-FD101SN

Kosnic 4.5W LED GU10 PAR16 Very Warm White - KTEC4.5PWR/GU10-S27

I took out the halogens, each had its own transformer, and simply connected the LED units to the 240v supply at each lamp - and the holes in the ceiling were the same size  :thumbsup:    Even better was that I sold all the halogens on Gumtree for about 50% of the LED cost ;D

While I was at it I changed lots of 240v halogens in wall lights around the house for LED bulbs - just a straight replacement in the light fitting.  We did get a few trial bulbs to check the light colour/brightness etc


Re: LED room lighting (again)
« Reply #361 on: 23 November, 2021, 08:05:00 pm »
Received wisdom seems to be that if you fit LED fixtures, they'll fail in a couple of years and you'll need to replace them (inevitably with something requiring a different size hole, or at least visibly non-matching).  If you fit GU10 or similar fixtures, they'll be flickery shit from the outset, but at least you can change the lamp when it fails.

I guess it depends on your (in)tolerance to flicker. We’ve had mains GU10 LED replacement bulbs for several years in both kitchen and bathroom. We don’t notice any flicker, and the bulbs have been more reliable than halogen ones.
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Re: LED room lighting (again)
« Reply #362 on: 23 November, 2021, 08:09:59 pm »
240V bulbs mean fewer parts and guaranteed to work rather than hoping your LEDs match the transformer.

The Ikea ones in waterproof, fireproof fitting (i.e no airflow above or below) in my bathroom have been going for years and I have a bad habit of leaving them on all the time.

Kim

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Re: LED room lighting (again)
« Reply #363 on: 23 November, 2021, 09:46:34 pm »
Received wisdom seems to be that if you fit LED fixtures, they'll fail in a couple of years and you'll need to replace them (inevitably with something requiring a different size hole, or at least visibly non-matching).  If you fit GU10 or similar fixtures, they'll be flickery shit from the outset, but at least you can change the lamp when it fails.

I guess it depends on your (in)tolerance to flicker. We’ve had mains GU10 LED replacement bulbs for several years in both kitchen and bathroom. We don’t notice any flicker, and the bulbs have been more reliable than halogen ones.

The problem with flicker is that the manufacturers (other than Sansi) don't tell you how much there is.  So you're stuck with buying an assortment of lamps, and either seeing obvious stroboscopic effect; measuring the flicker using flicker-measuring equipment; destructively reverse-engineering the lamp; or installing them and seeing if they give you seizures/migraine/sensory overload/nonspecific headaches/low-level eye-strain.  Redo from start when they manufacture a different batch.

I can see 100Hz flicker in my peripheral vision plainly enough, up to typical microprocessor PWM frequencies if I'm paying attention to a moving object.  But beyond about 1kHz I need test equipment.  It doesn't bother me particularly, but I'm not sure that it's a good idea to read by it, even if you don't see artefacts.

The problem with GU10 lamps (and similar form-factors) is that they don't leave a lot of space for smoothing capacitors...

Feanor

  • It's mostly downhill from here.
Re: LED room lighting (again)
« Reply #364 on: 23 November, 2021, 10:25:28 pm »
Yes, and so back to my original q:

With a 240v GU-whatever LED lamp, all the chopperising, smootherising ( or lack thereof ), constant-currantizing for the LEDs has to happen within the body of the lamp itself. The smootherising of the 240v to chopperised LV is compromised by lack of space.

But with a 12v LED, all the chopperising and smootherising is done in the external psu, with space to do it properly. So what remains to be done in the lamp? only the constant-currentizing for the LEDs, because the psu provides a constant-voltage clean 12v.  Does the constant-currantising involve a further stage of chopperizing and un-smoothing? Or is it a more linear thing? I've never ripped one apart. But my hunch is that there is rather less electronics in a 12v lamp than a 240v one. But I don't know.

Kim

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Re: LED room lighting (again)
« Reply #365 on: 23 November, 2021, 10:43:37 pm »
Me neither.  It's a good question...

To the Youtubes!

https://www.youtube.com/watch?v=i-Roc5TLdnw

Dunno how typical that is, but it would appear to be the full shebang, operating at 12V.  Also, bonus cat.

Mrs Pingu

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Re: LED room lighting (again)
« Reply #366 on: 24 November, 2021, 10:52:54 pm »
A couple of weeks after we moved in here I replaced the last of the evil halogen pretending to be incandescent bulb with LED. One of them failed already, that's less than 3 months!
Lumilife is the brand for those interested.
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Re: LED room lighting (again)
« Reply #367 on: 24 November, 2021, 11:58:44 pm »
A couple of weeks after we moved in here I replaced the last of the evil halogen pretending to be incandescent bulb with LED. One of them failed already, that's less than 3 months!
Lumilife is the brand for those interested.
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Re: LED room lighting (again)
« Reply #368 on: 25 November, 2021, 07:38:18 am »
Yes, and so back to my original q:

With a 240v GU-whatever LED lamp, all the chopperising, smootherising ( or lack thereof ), constant-currantizing for the LEDs has to happen within the body of the lamp itself. The smootherising of the 240v to chopperised LV is compromised by lack of space.

But with a 12v LED, all the chopperising and smootherising is done in the external psu, with space to do it properly. So what remains to be done in the lamp? only the constant-currentizing for the LEDs, because the psu provides a constant-voltage clean 12v.  Does the constant-currantising involve a further stage of chopperizing and un-smoothing? Or is it a more linear thing? I've never ripped one apart. But my hunch is that there is rather less electronics in a 12v lamp than a 240v one. But I don't know.
12 V house lighting traditionally runs from conventional transformers that put out 50 Hz sine waves. An LED lamp will have to have a rectifier to allow for that, which will also allow for it to be inserted either way round if the power supply provides dc.

A current control device is needed, and that has to be in the lamp as a transformer will produce a fairly constant voltage, and there may be several lamps in parallel. If a linear current limiter is used, it will get hot, and how hot it gets will depend on the supply voltage. I can see why the lamps will often contain switch-mode regulators.

The switching frequency of a switch-mode regulator is often high enough to either make the flicker imperceptible, or mean that a small and cheap capacitor will virtually eliminate it. High-frequency switching stops there being an audible squeak and means that the inductors needed are smaller.
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Feanor

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Re: LED room lighting (again)
« Reply #369 on: 25 November, 2021, 09:49:58 am »
After watching the 12v LED lamp tear-down video Kim posted, and reading up some more, my thinking is currently(!) along these lines:

I noticed that some 'transformers' eg 12v DC 6w units designed to power a single 5w LED make claims to produce lower flicker, and greatly extend the lifespan of the LED lamp. They don't seem to offer up any explanation or substantiation of these claims, however.

But looking at the schematic in the lamp tear-down video, the input stage is a straightforward discrete bridge rectifier, and large electrolytic smoothing designed for 50Hz, when running the lamp from a 12v AC supply.

This cap is probably the principal point of compromise and failure in the design, I'd have thought.
It will likely have a fairly poor ESR rating, and its voltage rating will be close to it's operating envelope I expect.

So with a 12v AC supply, I'd expect the 'DC'-ish supply to the current regulator to be fairly poor in terms of 50Hz ripple, which might account for visible flicker.
It would depend on how well the high frequency current regulator is able to deal with that.
i can imagine there might be potential for beat frequency flicker, too.

Running such a lamp from a 'clean' 12v DC, the electrolytic cap really doesn't have anything to do, so it's compromised spec will be much less of an issue.  I can see how this might extend the lifespan of the lamp, as the cap will likely last longer.  The high frequency current limiter will be getting a clean DC at all times, and so the only flicker I'd expect at this point will be from this high frequency regulator. The video did not put a 'scope on the chopper, so we don't know the frequency.

I've bought some suck-it-and-see parts: a small selection of LED lamps, and a couple of DC-output 'transformers', and a bag of Wago 224-112 connectors and Wago Light enclosures, in case there's going to be a bunch of wiring. I'll test the lamps against the in-situ 50w AC 'transformers', and compare the results against the new DC ones.


Re: LED room lighting (again)
« Reply #370 on: 25 November, 2021, 09:56:08 am »
Following on from another thread where a 50w MR16 Halogen downlighter nearly set my house on fire, I'm looking to replace them with LEDs.
The existing fittings in various rooms are set into holes in the plasterboard, some are 65mm and some are 70mm holes.

What's the general approach to this these days?

1) Retain the existing fittings, and use like-for-like 12v LED lamps.  This might require new transformers / SMPSUs, if the existing ones have a minimum load which the 5w LEDs don't reach.

2) Retain the existing fittings, and use 240v MR16 lamps, ditching the transformers / SMPSUs.

3) Replace the entire fitting with a dedicated LED unit.

My gut reaction is (1), for the following reasons:

- Having the 240v - 12v PSU external means it can have better thermal management than trying to cram it into the tiny space in the lamp itself, leaving only the 12v LED driver in the lamp;

- I'm not sure the existing fittings / connectors are rated for 240v. But then again they were marginal for the current for 50w @ 12v!  I think I'd prefer to run them at 12 v and the 500mA or so a 5w LED will take.

- I don't want to have to re-drill / patch plasterboard for new fittings which will no doubt be different diameters to my existing mix of 65 / 70 mm 'oles.

So general advice?
And any particular brand of 12v 50w equiv LEDs you'd recommend?

I swapped out my halogen GU10 for LED some time ago, but despite trying to get "better" quality units, I was uncomfortable with them in my non-fire rated downlighters, given the potential for component failure and effect on the fitting. What I have done is swap for Phillips GU10 which are high CRI and encased in glass, so I have no concerns about fire.

Kim

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Re: LED room lighting (again)
« Reply #371 on: 25 November, 2021, 11:13:17 am »
Isn't fire rating of downlighters about their effective properties as a hole in the (fire-rated) ceiling, rather than anything to do with their propensity to catch fire themselves?

Re: LED room lighting (again)
« Reply #372 on: 25 November, 2021, 12:30:12 pm »
This cap is probably the principal point of compromise and failure in the design, I'd have thought.
It will likely have a fairly poor ESR rating, and its voltage rating will be close to it's operating envelope I expect.

So with a 12v AC supply, I'd expect the 'DC'-ish supply to the current regulator to be fairly poor in terms of 50Hz ripple, which might account for visible flicker.
It would depend on how well the high frequency current regulator is able to deal with that.
i can imagine there might be potential for beat frequency flicker, too.


I would agree that the capacitor may be overstressed. However, the visibility of flicker depends on the modulation depth, or how dark the dark times are compared to the bright times. The bad flicker (VW tail lights*) comes from 100 % modulation depth, so they turn off completely, and if that is combined with a poor mark space ratio (the light is only bright for a short part of the cycle) then flicker is very visible.

A capacitor followed by a regulator is likely to have reduced modulation depth, in that it may well not turn off completely, and a good mark space ratio, so that it is at or near full brightness for most of the time, so I think that flicker will be minimal. I don't think that you will get beat frequency modulation between 100 Hz rectified mains and 20 - 100 kHz switching frequency.

You can rectify and smooth the mains before feeding it to the lamp. That allows you to fit a generous capacitor.

*The VW tail lights were on for 1 ms and then off for 9 ms, so flickering at 100 Hz. They were far, far worse than discharge lights (fluorescent or sodium street lights) running from 50 Hz mains, so also modulated at 100 Hz, but fading to nearly off and fading back up every 10 ms, and spending a lot of time near full brightness.

My example from a car built 15 years ago is here:- http://www.malin.me.uk/vw.jpg It's a photo of a stationary car taken with a large amount of deliberate camera movement. The red dots are the VW tail light. The orange band with bright and dark bits is a sodium street light. The white line is a 12 V incandescent car light.
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Feanor

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Re: LED room lighting (again)
« Reply #373 on: 25 November, 2021, 12:46:06 pm »
This cap is probably the principal point of compromise and failure in the design, I'd have thought.
It will likely have a fairly poor ESR rating, and its voltage rating will be close to it's operating envelope I expect.

So with a 12v AC supply, I'd expect the 'DC'-ish supply to the current regulator to be fairly poor in terms of 50Hz ripple, which might account for visible flicker.
It would depend on how well the high frequency current regulator is able to deal with that.
i can imagine there might be potential for beat frequency flicker, too.


I would agree that the capacitor may be overstressed. However, the visibility of flicker depends on the modulation depth, or how dark the dark times are compared to the bright times. The bad flicker (VW tail lights*) comes from 100 % modulation depth, so they turn off completely, and if that is combined with a poor mark space ratio (the light is only bright for a short part of the cycle) then flicker is very visible.

A capacitor followed by a regulator is likely to have reduced modulation depth, in that it may well not turn off completely, and a good mark space ratio, so that it is at or near full brightness for most of the time, so I think that flicker will be minimal. I don't think that you will get beat frequency modulation between 100 Hz rectified mains and 20 - 100 kHz switching frequency.

I think because the buck regulator in the lamp provides current to the load from the inductor and diode during the off-time will help reduce the modulation depth too.
I don't know how typical the design in the tear-down video is, but I expect it's fairly standard.

I've just tried some Aurora lamps from Screwfix as direct drop-in replacements for the 50w halogens, using the existing in-situ 12v AC 'transformers'.
They seem to work just fine, with no visible flicker.
Which is good, since the 'transformers' are not accessible without more plasterboard cutting and patching faff.
And frankly, I've had enough of that recently. (But my plastering skillz have come on a bit!)

I'll start swapping out other ones too, and will only replace 'transformers' as required, to minimise faff.

Jaded

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Re: LED room lighting (again)
« Reply #374 on: 25 November, 2021, 02:47:32 pm »
Update with what we have in our kitchen now.

JCC JC94174  7W non-dimmable.

Nice pieces of kit and a 10 year warranty.

9 years into the warranty for these and no failures.

Did have a failure in a set put in two  years later, and it was replaced, with only COVID fuss (no one in warehouse as it was lockdown).
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