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General: LED bulk purchase.

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  1.  
    Hi,
    Has anyone found a supplier of high quality GU10 LED's that will offer discounts for large orders? I need approx 70 for my new build and money is tight. I love Light Planets LED's but I do not think my budget will stretch to 70 unless I buy in stages. I do not doubt the quality though. Are some of the cheaper units cheap for a reason? I notice some only give a 12 month guarantee? Thanks in advance,
    Gusty.
    • CommentAuthortony
    • CommentTimeApr 11th 2011
     
    I am waiting a year before buying the price is coming down fast and the quality improving too.
  3.  
    Tony may well have the right idea, 12 months time could be noticably cheaper

    these lot seem to have a god range , might be worth a try
    http://www.orlight.com/products/led/
    Also seen GU10 LED for £14+vat
    http://www.tlc-direct.co.uk/Products/LTGU7WW.html

    Wookie was discussing a while back that perhaps we should be looking at light designs more suitable to LED tech. rather than just using old style halogen bulb designs.
    Designs that allow the LED to remain cool. such as the cut to size strips fitted in purpose made pelmet or uplights .
    http://www.orlight.com/products/led/ORLR6012CH/

    Already had some call backs on GU10 LED in downlights , with the lamps going after less than a year.
    Probably heat related problem.
    cheers Jim
  4.  
    Thanks for the advice. The majority of GU10 LED's I have seen have fairly thick cooling fins. The LP's fins are much thinner and the units have more of them. I would think this provides better cooling and takes heat away more efficiently. I wonder at the moment if you do get what you pay for with GU10 LED's. I will not need to purchase any before mid summer so I may wait and see if things have moved on if prices are dropping and quality is also improving,
    Thanks,
    Gusty.
    • CommentAuthorwookey
    • CommentTimeApr 12th 2011
     
    gutsy - you are still mounting the light in a hole, possibly a sealed hole (upstairs). It's a design for incandescents.

    LEDs, including the heat sink, only need to be about 7mm thick so are idealy suited to flat panels or strips. As you say, it is possible to properly eingineer an inset GU10/MR16-type light but it needs a sodding-great heat sink and IMNSHO it's just not very smart. I am amazed by the inertia in the system on this point. Talking to LED suppliers they shrug and say 'that's what people want'. So they are still making these silly things, and we are all still buying them.

    Well, we people here are freer-thinkers than average and we should be doing something more sensible. Look for strips and panels. (In my case I've just made my own - big sheet of brushed aluminium, cut into pieces about 10x20cm, put two LEDs on it - total cost under a tenner for 700 lumens @6W, and it stays very cool - barely warm. The tricky bit is a diffusing optic of some sort because the bare LED is too bright to look at. Anyone who has good ideas for a source for that (preferably that looks nice), do speak up.

    I'm imaging something jamjar-lid shaped.
    •  
      CommentAuthorSteamyTea
    • CommentTimeApr 12th 2011
     
  7.  
    Wookey,
    How do you get a light fitting you have made yourself signed off by your sparky or BCO? My guess is you are just fitting LED's to save power so it does not involve a spaky or BCO,
    Gusty.:confused:
    • CommentAuthorwookey
    • CommentTimeApr 12th 2011
     
    No idea, but these will be going in my new extension so I guess I'll get to find out. Completely bonkers that a set of 3W LEDs falls under the purview of a sparky or BCO. If I get any grumbling I shall explain to them quite forcibly how this is much better engineering than the usual stuff people put in houses.
    •  
      CommentAuthorjoe90
    • CommentTimeApr 13th 2011
     
    Wookey,

    Being a freer thinker like yourself and an avid DIyer would you post the components of your LED light as I would like to attempt to build some myself or are you looking to patent your idea?
    •  
      CommentAuthorDamonHD
    • CommentTimeApr 13th 2011 edited
     
    Wookey: as it happens I'm testing a (slightly insipid) strip of Maplin LED lamps in the kitchen, for a review later. But they are marketed as 'decorative' which is an excuse for 'inefficient' I think!

    Could you remind us / me which ones you are working with and their lm/W? I ought to pull my finger out and build a comparative set for the review.

    Rgds

    Damon
  11.  
    •  
      CommentAuthordjh
    • CommentTimeApr 13th 2011
     
    Posted By: wookeyThe tricky bit is a diffusing optic of some sort because the bare LED is too bright to look at.

    Perhaps a concave lens over the LED, then a gap and an outer opal or prismatic diffuser?

    Or maybe a diffraction grating, if you can find them cheap enough?
    • CommentAuthorwookey
    • CommentTimeApr 13th 2011 edited
     
    My lights are using these:
    Cree XPGWHT-L1-1T-R5 90-100lm/W
    CREE XP-G R5 on Ceramic PCB 90-100lm/W
    CREE XR-E 7090 Q4 on Star PCB 71lm/W

    I bought from http://www.led-tech.de/ but http://leds.de/ are good too.

    I see that the Cree XM-L T6 has appeared since I went shopping, another 90-100lm/W LED, that produces 900 lumens from a 5x5mm LED, For 6 euro: http://www.leds.de/en/High-Power-LEDs/Cree-High-Power-LEDs/Cree-XM-L-T6-white-910-lumen.html

    I simply bolted/glued (with artic silver) a couple of LEDs to a sheet of aluminium. Make small holes to take the wires out the back. Find an efficient power supply. I picked this one: 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 which will drive up to 8 3W LEDs. I am planning 4-6 to light the front room.

    An alternative is to fit them in a strip like this: http://www.led-tech.de/en/High-Power-Zubehoer/LED-Profil-CoverLine-c_106_151.html

    I did get these parts a month or three back, find that they worked and failed to actually install them for a good winter's testing, due to being a bit busy. I will stick them up and take some photos at some point.

    The question of how best to hold the panels to the roof remains. Some kind of hidden fixing would be nice.
    •  
      CommentAuthorDamonHD
    • CommentTimeApr 14th 2011
     
    Thanks Wookey: good info. Probably need to buy myself a few for R&D purposes...

    Drilling the Al is my next worry!

    Rgds

    Damon
    •  
      CommentAuthorSteamyTea
    • CommentTimeApr 14th 2011
     
    <blockquote><cite>Posted By: DamonHD</cite>Drilling the Al is my next worry</blockquote>
    Make your life easy for 60 quid

    http://www.diy.com/diy/jsp/bq/nav.jsp?action=detail&fh_secondid=10957556&fh_location=//catalog01/en_GB/categories%3C{9372015}/categories%3C{9372047}/categories%3C{9372201}/specificationsProductType=bench_drilling&tmcampid=4&tmad=c&ecamp=cse_go&CAWELAID=656841560
    •  
      CommentAuthordjh
    • CommentTimeApr 14th 2011
     
    Posted By: DamonHDDrilling the Al is my next worry!

    Drilling ali is very easy. Just a light centrepunch tap first to centre the drill. You can even use a nail as the punch, as the ali is so soft.

    But a drill press will certainly make it easier!
    •  
      CommentAuthorDamonHD
    • CommentTimeApr 14th 2011
     
    Thanks for the reassurance: I've got several things to do ahead of that point, and some non-heatsink stuff to do, so no huge panic!

    Rgds

    Damon
    • CommentAuthorCWatters
    • CommentTimeApr 15th 2011 edited
     
    Thanks for those german links Wookey. Regarding the one you purchased...

    http://www.leds.de/en/High-Power-LEDs/Cree-High-Power-LEDs/Cree-XM-L-T6-white-910-lumen.html

    Did you get the version with or without PCB?

    Before you stick several onto one bit of metal perhaps worth checking thats ok as the heat sinks may not be
    electrically isolated (not that this allways matters)?
    EDIT: Data sheet for 5mm sq version says electrically neutral thermal path so looks like that's ok.
    •  
      CommentAuthordjh
    • CommentTimeApr 15th 2011
     
    Posted By: djh
    Posted By: wookeyThe tricky bit is a diffusing optic of some sort because the bare LED is too bright to look at.

    Perhaps a concave lens over the LED, then a gap and an outer opal or prismatic diffuser?

    Just had a better idea - invert it. Instead of a concave lens, use a convex mirror. Either a ball bearing or a domed mirror screw cover - http://www.hart-wholesale.com/mirror.htm#dome - just in front of the LED. Then a diffuser.
    • CommentAuthorwookey
    • CommentTimeApr 17th 2011
     
    Cwatters. I didn't buy a T6, because they are new since I went shopping. But I did buy some stars and some ceramic-only mounts to see how they compare. If you can see the LED then the ceramic mounts look neater, and presumably provide a lower thermal resistance (but I'd have to check the datasheets). They'd have to be mounted by glueing, which might put (thermal) resitance up again. The stars can easily be bolted down on thermal paste. I was planning to do some sums (and good old-fashioned experiments) to compare mounting methods.

    djh - can't see the point of a lens (or convex mirror), when the beam angle of the bare LED is good for general room lighting (~120 degrees). All I want is something to diffuse it a little so that the very bright light point is not distracting/annoying. I see I can buy a huge sheet (3m2) of frosted acrylic for £112, which is enough for 1000 60mm dia discs (or single 100mm discs for £5.30). I wonder what glue to fix it with (cyanoacrylate?). I feel some more experimentation coming on.
    •  
      CommentAuthorSteamyTea
    • CommentTimeApr 17th 2011
     
    Posted By: wookeyI wonder what glue to fix it


    Methyl Ethyl Ketone (MEK) is what we used to stick things to it.
    • CommentAuthorCWatters
    • CommentTimeApr 17th 2011
     
    I think I'd run them somewhat below the max brightness. Looks like the new T6 is pretty good at half max power. Might live a lot longer if cooler.
    •  
      CommentAuthorDamonHD
    • CommentTimeApr 17th 2011
     
    More efficient (lm/W) if run well below max power.

    Right at the other end of the scale I'm running a nightlight on a few milliwatts which is enough for our upstairs landing, and lasts several months on a single charge of 4 x AA NiMH batteries. I suspect that it is rated for hundreds of milliwatts at a rather lower efficiency than I'm getting.

    http://www.earth.org.uk/LED-lighting.html#homebrew-nightlight

    Rgds

    Damon
  24.  
    SteamyTea,
    I used to use MEK years ago but it was a chemical for removing oil and grease back then I think? If you are playing with that stuff pop your mask on and open your windows!!!!
    Gusty.
    •  
      CommentAuthorSteamyTea
    • CommentTimeApr 24th 2011
     
    Think that is why the changed the formula of Bostik, I like marker pens too :wink:
  26.  
    Report on LED lighting
    http://apps1.eere.energy.gov/buildings/publications/pdfs/ssl/brilliant-solutions_brochure.pdf
    "Pretty thorough and authoritative report, at the cost of being 18 months old."
    from the link below
    http://www.aecb.net/forum/index.php/topic,2806.0.html
  27.  
    Marker pens!!! now your talking, what colour?
    :rasta::peace:
  28.  
    I like the LP's LED's but technology seems to be getting better and so prices are still very high for the better units,
    Gusty.:sad:
  29.  
    http://www.midshireselectricals.co.uk/aurora-gu10-par16-cree-dimmable-led-8-5w-2700k.html

    Heard good reviews on this one from other sparkys , not tried one yet

    8.5W dimmable GU10 , LED with big heat sink £24
    • CommentAuthorSprocket
    • CommentTimeJul 13th 2011 edited
     
    re; those Aurora GU10s

    We've been using those here a while. Really good.
    I would even say better (just slightly) than our previous best, the Philips master - those were the first things that seemed like an acceptable replacement for the huge number of 50W halogen GU10s in our kitchen.

    But nothing else comes even close to those two for intensity, spread and quality of light.

    When we bought they were 30 quid apiece though so not cheap :-(

    Watch out if you have dimmers though. Traditional leading edge dimmers don't like lots of LEDs.

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