Marketing waffle. NxtGen sounds like a brand name. Efficiency is about 80ish lumens/W, so nothing particularly outstanding there.

What are people's views on bulbs using a small number of LEDs with lenses vs an array? Obviously the smaller number must be more recent, higher output units but that neccessarily make them more efficient or reliable.

Read this, from the people that should know:
http://eandt.theiet.org/magazine/2012/08/leading-lights.cfm

Posted By: Simon StillI've started thinking about the lighting spec for our build and wondering whether I should be thinking about about running LV cabling and using a smaller number of large transformers

There has been discussion on this elsewhere on this forum.

Posted By: CWatters
It's not always true that bulbs with fewer LED are newer.

Indeed. There is a significant, fairly recent trend towards using a number of surface-mount 5050 or 3535 LEDs instead of big 1-5W power LEDs. No doubt because they are cheaper overall per lumen.

It really doesn't matter exactly what LEDs are used so long as the efficiency, physical size/format, beam angle/shape, and colour temp/CRI, and supply current/voltage suit your requirements.

I'd aim to have one transformer per switched segment of lighting, so the switching is still mains but you don't have 3+ transformers in the ceiling of one room/section. Much better than having 15 of them, one in each 'bulb'. You could go for a big central PSU to do the whole house and switch digitaly or with DC, but it'll be hard to make that efficient as a PSU manly enough to run alll the lights in the house will normally be run at quite a low power output and I bet they all waste a load of power at low duty/everything off (overnight/away). And I bet it's all really expensive because now you are into grand designs, and lighting designer, territory.

One thing to watch for with individual supplies is FM radio interference and start-up delay. Both can be annoying on cheap and cheerful kit.

<blockquote><cite>Posted By: wookey</cite>I'd aim to have one transformer per switched segment of lighting, so the switching is still mains but you don't have 3+ transformers in the ceiling of one room/section.... You could go for a big central PSU to do the whole house..., but it'll be hard to make that efficient ....and I bet they all waste a load of power at low duty/everything off (overnight/away)</blockquote>

That all makes sense. More standardised (so easier to replace), small and easily hidden, transformers as well that can be located near the lights.

Quick look suggests you can get:

12V MR16
24 x 5050 LEDs
claimed 450 Lumens
60 degree beam angle.

I think these might be an interesting option for a new install.

Some sellers compare them to "50W Halogen" but I think it's a bit missleading. I reckon they produce about the same light as a 230V 50W halogen not a 12V 50W halogen. Perhaps best use the closer spacing you would use for a 230V Halogen compared to a 12V Halogen.

I bought some gu10 3 x 2 watt led from aliexpress. Inital use looks similar brightnees to a 50w halgon, but only uses 12 watts for 3 lights (watt-a-meter). Clamied lumens was in the 450 range, but I don't have a meter yet. Best of all I bought 100 (a few spares to cope with no name failures) at a total cost of £200.

Using MR16s in a new install means you are doing it wrong IMHO. They can make sense for retrofit, but otherwise are a crappy technology. .

Posted By: wookeyUsing MR16s in a new install means you are doing it wrong IMHO. They can make sense for retrofit, but otherwise are a crappy technology. .

What do you propose? Obviously fittings specially designed for LEDs from the outset would be great but all the ones I've seen are v. expensive by comparison.

Posted By: wookeyUsing MR16s in a new install means you are doing it wrong IMHO. They can make sense for retrofit, but otherwise are a crappy technology.

Can you expand on this? My previous thoughts from other discussions were that the separate transformers were more efficient and reliable than the GU10s. The only downside of MR16 LEDs are that they are not dimmable AFAICS

Can you expand on this? My previous thoughts from other discussions were that the separate transformers were more efficient and reliable than the GU10s. The only downside of MR16 LEDs are that they are not dimmable AFAICS

I suspect wookey is refering to the fact that wrapping LEDs up in a glass bulb with an unnecessary reflector isn't the best way to get the heat out and ensure long life.

I suspect wookey is refering to the fact that wrapping LEDs up in a glass bulb with an unnecessary reflector isn't the best way to get the heat out and ensure long life.

Right. And making holes in the ceiling means they need to be fire-rated, and is bad for airtightness, and you only need a hole because of this form-factor.

Yes they are cheap, and widely available - that's about the only good thing about them.

syngappa - could you really not find constant-current supplies plus bare LEDs, suitably mounted? It's pretty cheap to DIY (~£8 per 3W fitting) - I don't quite know why they can't easily be bought yet for nuppence. I guess it's because everyone is asking for MR16s.

There was a recent thread on here or Navitron where I found some linear tape that was about 140lm/m (i.e. not too dingy and not too bright) and efficient and not expensive, which I reckon is an excellent way of lighting a room. Doing a load of this in my house is getting very close to the top of my list. I'll post my results.

Posted By: wookey
syngappa - could you really not find constant-current supplies plus bare LEDs, suitably mounted? It's pretty cheap to DIY (~£8 per 3W fitting) - I don't quite know why they can't easily be bought yet for nuppence. I guess it's because everyone is asking for MR16s.

biggest trouble was this was a new-build and hence had to be inspected and signed off - and although I may have taken a few liberties around the lighting I don't think that bare LEDs araldited to lumps of aluminium and hung from the ceiling would have found much approval!

I did get the electrician to install a number of 5a round pin sockets though, so once everything is signed off I can bodge away to my heart's content. The electrician's take on this was that he was supplying a socket in conformance with the regs and would sign that off - and whatever I then plugged into it was an "appliance" and hence my own stupid problem.

We have a (very) low ceiling so downlights were the only practical option - but a warm roof so no concerns about draughts/heat loss. I found some MR16 mounts called "ansell icage" that have an open frame which means that they are fully ventilated to the void so helping heat dissipate , but have an intumescent seal that fills the frame in even of fire. LED tapes under the kitchen units and on the bedroom ceiling are great though, and it's all controlled and dimmed via a central arduino "brain"

With hindsight I would have used more LED tapes but I think you need a good height room to put them in and use them as uplighters. Biggest problem I found was colour consistency - they can be found on ebay for ~£15 for 5M but the colour of "warm white" varies between shocking bright white with a blue tint, and nice warm white.

-Steve

Posted By: wookeyI need to get mine signed off too, but if they argue about my DIY lights I'm prepared to take it all the way to top. It's good engineering and I can defend it. Being ahead of the curve is not a bad thing :-)

Excellent, thank you - the boundaries on this sort of thing need a bit of a shove.

It seems to me, after a brief perusal of mildly relevant documents, that as long as you meet the requirements of SELV (mostly a double insulated power supply and appropriate separation of cables) and have appropriate over-current protection (DC rated fuse - in case a short causes your constant current power supply to melt) there ought not to be any problem. It might take a while to find an electrician who'll actually sign, though. I suspect it'd need somebody who specializes in “odd” systems but should be doable.

Ought even to be OK in most of the bathroom zones, depending on how many LEDs you have in each string (lower voltages required).