Wookey,

I would be interested to see your target spec for cheap, efficient halogen downlighter. As you can imagine, we are working on something along those lines, so input would be much appreciated.

Evan. The strip I bought no longer seems to be on the site. It was one of these, but already mounted in an ali profile and gooped in to make it IP67: http://www.leds.de/en/LED-strips-modules-oxid-oxid-oxid-oxid/High-power-LED-strips/High-Power-SMD-LED-strip-white-600mm-1200lm-12V.html (and I got 3 for 56 euro).

Here are some that are significantly more efficient at 105 lm/W: http://www.leds.de/en/LED-strips-modules-oxid-oxid-oxid-oxid/SuperFlux-LED-strips/ (40 euro)
and there is a profile to mount them in on that page to mount them in (15 euro). There is a wider range of profiles and mounts on this site: http://www.led-tech.de/en/High-Power-Supply-c_106_0.html.

An option for the DIY-inclined I've just worked out for lighting a room is
using the heatsink-profile LT1205 (13 euro) and LT0938 PCB (6 euro)which can take up to 8 power LEDs. You could put 6 XR-Es (7 Euro each) on there, running them at 700mA (driver is 8 euro). That would provide approximately 1000 lumens which is enough to light a 3m2 room.

The neat bit about this arrangement is that you can split the LEDs up however you see fit. If it was me I'd install each 3cm long LED segment containing one LED separately so there might be two rows of 3 across the roof, providing even lighting. The spec doesn't mention it but I'm pretty sure you could put the newer XP-G LEDs on instead which are only 5 euro each, but 130 lm/W, so that would bring the LED cost for 1000 lumens down from 42 euro to 15 euro (and use a 1A driver), or 25 euro if you stick to 700mA. In fact this seems like such a good idea I think I'll buy the bits and try it :-)

Lightplanet. My vision for LEDs is little ali plates (maybe 10cm squared? - whatever is needed for the heat dissipation) with one or two bare LEDs on them. You fit as many of these as you need to get enough light for the room, probably running them at about 200 lumens each. Get at least 85 lm/W, preferably over 100. Run the lot off one driver unit, in series, current control (so no wasted power on resistors to match them to CV drivers. Find a driver unit that is at least 85% efficient but still around 10-12 quid. Each LED luminaire is around a tenner too. This gives you very low-profile lighting - only about 10mm thick, and the units could just be glued or velcroed in place without compromising airtightness in the ceiling. The awkward bit is wiring, as always. Could you run surface wiring and make a feature of it (e.g with a little half-moon slimline conduit?) otherwise it gets to go in the ceiling as usual.

For a more conventional 'one big light' concept the new chip-on-board LEDs look interesting: http://www.leds.de/en/High-Power-LEDs/Chip-On-Board-LEDs/Bridgelux-LED-Array-BXRA-C1202-white-1320-Lumen.html
that's 1300 lm at 98 lm/W for 30 euro (and you can turn it up to 2000 lm).
Stick that on a heat sink plate and let it light the room.

I really don't like the 'lamp in deep recess' idea as you get annoying holes which allow moisure where you don't want it, and/or leave the heatsink stuck in some insulation. We can make flat lights now - so I reckon we should.

Wookey, I'm sure it's easy when you know how - but never having even soldered anything in my life (yet) such diy lights seem rather daunting (and I don't have the money to make mistakes) - however the cost per lumen you quote is very tempting, even affordable! If you do do it perhaps you could post a couple of pics of the key points in the process. I had to order my son's bedroom stuff in a big hurry but the next job is the new kitchen - and I' hope to have a little more time to prepare for this little undertaking.

Alternatively, what's your best recommendation for a 'plug and play' single point LED - ie connect the +/- and Earth up to the mains and switch (non-dimmed) and 'see the light'. Ta alot.

Posted By: CWattersWookey - Re the wiring..
Perhaps if the exposed wiring designed to be a feature? eg wiring provided in say 1m long rigid chrome tubes with plug one end socket the other so that a matrix of LEDs on a 1m square 2D grid could be constructed.

I like that idea

Another way to conceal wiring is to run it along the corner of the wall and ceiling and then cover with coving. Gets you part of the way there at least.

Cwatters. You may be techincally right about the wiring regs but I'm afraid I'm just going to laugh in the face of anyone who tells me I can't wire up ~10W of LEDs in a room - that's just total madness. There is arguably some justification in fretting about LV wiring for crazy arrays of 1kW of halogens, but there is no way you can generate any meaningful risk with 1A of LED-driving current. Introducing such regs at a time when lighting power is about to drop to 'not much' is at best 'unhelpful'. Don't get me started about the insanity of it all...(My new extension is going to have maybe 1 socket and 1 pendant lightbulb, then building control and his pet electrician can bugger off...)

Gotanewlife. I wouldn't recommend mains LEDs - not efficient. You want a driver unit and some low-voltage LEd luminaires. For plug and play you could try any of the 'smartenergy massive' lights on this page 54 euro for 300 lumens: http://www.led-tech.de/en/LED-Luminaire/Wall-and-Ceiling-c_164_165.html
Buy three of them and an LT1279 supply: http://www.led-tech.de/en/LED-Controlling/Constant-Current-Power-Supply/Power-Supply-for-5-8x-3W-LEDs--230V--LT-1282_118_119.html to light a room. Just string the wires from supply to each luminaire in parallel - dead easy. For similar money the ecostar6+ already linked in this thread would also do the job (and that does plug into the mains as well as achieve reasonable efficacy).

The samsung modules here (10 euro for 130 lumens IP54, 60 lm/W) look like quite good value. No soldering although you get to pay 1.5 euro for the connectors. I guess it really needs some heatsink.

Here's a guy who's gone for the 'light your home with DIY LEDs' in a big way: http://www.dmcleish.com/MauiHome/ lots of interesting stuff in there, including a couple of my suggested 'LED on a sheet' lights.

Wookey: I'm not at all convinced that mass-produced mains LED lamps can't match LV DC efficiency when all is said and done (eg less wiring losses, more voltage elbow room for constant-current drivers, less protective-diode loss, blah, blah).

I have a nice sample V5 c/o LightPlanet that claims 100lm/W which beats hands down any DC LED lighting that I have at the moment. (Except possibly my homebrew ~3mW battery-powered nightlight with an amazingly god LED in it, nominally 60cd.)

Rgds

Damon

The advantage of 'one driver per lamp' is the ability to match them exactly, not have to deal with plonker end users like me plugging the wrong things into one another or the wrong way round, not having to put in protective stuff on the off-chance, etc, etc. And I suspect that the core circuitry is fairly settled for common variants, and only a few components (inductor, capacitor) need to be tweaked to cover most lamps.

Anyhow, I'm not here just to diss your ideas! %-P

Rgds

Damon

How many domestic homes have their lighting done by 'lighting designers'. Aren't most of them still done with one pendant fitting in the middle of each room? And most of the rest have an array of MR16s for no particular reason other than it's cheap and effective?

You're quite right that it will take a while for people to realise what they can do with LEDs, but the lighting designers are already catching on, and they suddenly have _so_ many more options than they ever did with halogens. I can't believe it'll be long before they (nearly) all become huge LED enthusiasts.

For 'normal people' an array of little LED luminaires isn't much different from an array of MR16s in overall effect - indeed it can be made to look almost identical. I reckon most people aren't that bothered and just want 'not too blue'.

Personally I'm a fan of 'alien autopsy white' as it's apparently known in the trade, and the corresponding maximum efficiency :-)

Friend of mine's spouse is a senior NHS bod and wants "operating theatre white": the V5 is her friend just so soon as she next feels the urge to splurge on-line (I lent her one to test)!

Rgds

Damon

As I thought "the GU50 providing 140,000 Lux @1m" !

There's also a LED version that's even better "High intensity illumination up to 160,000 Lux with near perfect colour rendition"

http://www.brandon-medical.com/uploads/Product%20Brochures/Medical%20Lighting/GLED%20HD-LED%20Brochure.pdf

Also designed to avoid disturbing airflow so it should be compatible with the MVHR. Sounds like just the sort of thing every eco-bling house should have :-)

Posted By: CWattersAh but is it dimmable :-)

You can dim each component colour individually, to best see the condition of the meat