Browse Forums Lighting + Lighting Design Re: LED downlights 61Jul 04, 2011 1:33 pm Too all those about the transformer you can get gu10 LEDs that don't need a tranny, I'm installing LEDs right now that take 240v, u just have to check the input voltage 12v = tranny mine take 85v to 250v = no tranny For all your electrical questions please pm me! Happy to help anyone Re: LED downlights 62Jul 04, 2011 1:39 pm gbtsec Too all those about the transformer you can get gu10 LEDs that don't need a tranny, I'm installing LEDs right now that take 240v, u just have to check the input voltage 12v = tranny mine take 85v to 250v = no tranny I thought that these just have the transformer built in? I would imagine a small inbuilt transformer would be less efficient? Re: LED downlights 63Jul 04, 2011 2:24 pm 3timesbuilda I thought that these just have the transformer built in? I would imagine a small inbuilt transformer would be less efficient? "240V LEDS" have an electronic power supply built-in. I doubt that they are any less efficient than an external supply, although with an external supply you can run one 12V power supply for multiple LEDs and reduce the overall system energy consumption. My main concern with an in-built supply is one heat dissipation. LEDs can generate a fair amount of heat (nothing like a halogen, but still significant) which is why you will see them fitted with heat-sink fins. If the power supply is internal then the heat from the power supply is combined with the heat from the LED itself and can lead to early failure if the device isn't engineered properly. Paul Re: LED downlights 64Jul 07, 2011 1:27 pm 3timesbuilda Think wise, Do your Genesis 16 Watt lamps use the CREE XM-L T6 LED? I note that these run at a claimed 100 lumen per watt which is exceptional efficiency if true. They also give out 975 lumens from the single LED. I would appreciate your comments on these. Do any downlights use these? For anyone interested, here is some info on this LED: http://www.led-tech.de/en/High-Power-LEDs-Cree/CREE-XM-Serie/CREE-XM-L-T6-Emitter-LT-1731_120_170.html The advancements being made in the LED field right now are quite large although replicating it in the real world is somewhat difficult, I will add below some issues. 1. 975lm is at 3A which is not realistic for off the shelf drivers. 700ma only yields 220lm in warm white. 2. no loss is taken into account for heat and ambient temperature. 3. no loss is taken into account for light loss through a lens I will give a breakdown from their datasheet of what lumens would most likely be in a down light with a single chip. (@700ma in warm white = 220lm) Losses to take into account: 8-10% loss from junction temp over 60C (this is pretty generous most lights run over 75C) 5-7% loss of light exiting the side of module 5-10% loss of light travelling through an acrylic lens (diffused lights are around 10-15%) so in the end a single chip best case scenario is only 180lm @ 2w. You could of course package 5 of these together to get 900lm @ 10w which is quite impressive but it would start to get expensive. Re: LED downlights 65Jul 08, 2011 1:10 pm Think_wise, Thanks for you response. I would like to ask you a few further questions. think_wise The advancements being made in the LED field right now are quite large although replicating it in the real world is somewhat difficult, I will add below some issues. 1. 975lm is at 3A which is not realistic for off the shelf drivers. 700ma only yields 220lm in warm white. Surely this is just a matter of a different transformer? With many LED downlights having built in transformers, this could be a non issue? I imagine that the issue here must be heat but not sure. Can you clarify this point for me please? think_wise 2. no loss is taken into account for heat and ambient temperature. The testing is done at 25C. I doubt that many downlights have big and effective enough heatsinks to keep this temp but you 60C seems achievable. We do this sort of stuff with PC processors all the time. think_wise 3. no loss is taken into account for light loss through a lens What is the main function of the lens? I mean are we talking about spreading the beam r smoothing the light pattern? I've see a lot of halogens run without a lens and wonder why the lens is used elsewhere. I would imagine that it acts as a heat trap giving a bubble of air around the emitter. think_wise I will give a breakdown from their datasheet of what lumens would most likely be in a down light with a single chip. (@700ma in warm white = 220lm) Losses to take into account: 8-10% loss from junction temp over 60C (this is pretty generous most lights run over 75C) 5-7% loss of light exiting the side of module 5-10% loss of light travelling through an acrylic lens (diffused lights are around 10-15%) so in the end a single chip best case scenario is only 180lm @ 2w. You could of course package 5 of these together to get 900lm @ 10w which is quite impressive but it would start to get expensive. According the these sites, at 350ma, the device performs at 160 lumens per watt: http://www.ledsmagazine.com/news/7/11/12 http://www.ledsales.com.au/catalog/index.php?main_page=product_info&cPath=148_188&products_id=802 http://flashlight-wiki.com/Cree If we apply the same ratio as the calc above, we still walk away with 130 lumens per watt. Pretty impressive in my book! 6 emitters placed into a downlight would give you around 780 lumens at 6 watts which is at least the equivalent of a 35W halogen and quite possibly a 50w halogen. It certainly beats your 13/16w downlight. So the main issue here would be cost ie. 6 x emitters at say $3 to $5 per unit ie. $18 to $30 for the emitters. Not too bad for what is very likely the most efficient downlight in the world and by a good margin. Every green organisation should want them not to mention every good home builder:). Also cooling 6 emitters may be easier and the lifespan of these (running at this low amperage) would probably be in the order of 100 000 hours true. I really think you should explore these and see if you can find any potential. What is the emitter you currently use? Personally I have ordered a torch/flashlight with 3 of these emitters. It should be really bright when running on high setting . I will let you know what I think of the light when the torch arrives. 3xb Re: LED downlights 66Jul 08, 2011 1:14 pm Worth also mentioning that one of those web sites claims 150lm/w at 700ma so only 3 emitters might be needed or 4 with a bit more output. Re: LED downlights 67Jul 08, 2011 8:14 pm "What is the main function of the lens? I mean are we talking about spreading the beam r smoothing the light pattern? I've see a lot of halogens run without a lens and wonder why the lens is used elsewhere. I would imagine that it acts as a heat trap giving a bubble of air around the emitter." The lens is for light control creating your desired beam angle, a reflector can also be used to do this but with possibly less control and also can cause more glare depending on the design. The majority of heat is at the base of the chip not the front so lenses dont really cause any adverse heat issues. I think those figures will most likely be cool white. The warm white will be less, I just got my data from the spec sheet I had on my computer so it could have been updated. In regards to the 3A driver the industry move is towards low current so not many people are making drivers over 700ma for the domestic market especially in dimmable versions. Internal drivers are always tough due to the heat, some roof spaces in QLD can approach 60+ degrees which is quite tough to combat. Any external driver needs to undergo fairly rigorous electrical safety testing for Australia if your wanting to sell the product legally so picking a fairly universal current 350/500/700 is always beneficial. We use a few different brands depending on the product, currently we use an epistar package for our down light as it utilises one red chip to get the 3000k without lumen drop and is quite cost effective. Although we are testing a Bridglelux, semicon and cree package for future models as pricing seems to be dropping. Re: LED downlights 68Jul 27, 2011 2:46 pm Does anyone know how these perform or have used the following LED downlight? http://www.halers.com/led_downlights/10765_0c.html Thanks Re: LED downlights 69Jul 27, 2011 2:55 pm LED techonology has not yet reached a mature phase in its cycle and considering the product life cycles of its predecessors, its pretty much in its infancy. I would wait for the technology to mature before comitting myself., Remember that you cant simply substitute a lighting type with LED's should you realize that its not working for you. Another thing to consider is CRI (Colour Redering Index). CRI is the measure of how faithfully, a light source cna render colour. For example, red and brown tones look very washed out when viewing in flouresent light. The same thing applies to LED light - check that out first. Suburbia is where the developer bulldozes out the trees, then names the streets after them. Re: LED downlights 70Jul 29, 2011 11:04 pm xanthrope LED techonology has not yet reached a mature phase in its cycle and considering the product life cycles of its predecessors, its pretty much in its infancy. I would wait for the technology to mature before comitting myself., Remember that you cant simply substitute a lighting type with LED's should you realize that its not working for you. Another thing to consider is CRI (Colour Redering Index). CRI is the measure of how faithfully, a light source cna render colour. For example, red and brown tones look very washed out when viewing in flouresent light. The same thing applies to LED light - check that out first. Assuming that the product in question doesn't perform as the one it's replacing which is not the case for a lot of LED products on the market. CRI is less of an issue than it was as even cheap chips can reach 80+ quite easily. Even in it's 'infancy' we have not audited a job that resulted in lower lighting levels with a minimum of 40% power saving. Re: LED downlights 71Aug 06, 2011 1:44 pm I have trialed an LED downlight that seems to work very well. I have subjectively tested them next to 50W halogens and I cannot pick a different in brightness or color quality. They are 13W, warm or natural white color, they do have a transformer supplied with it, dimmable, they have a gimble that ca be tilted. They are extremely similar to a halogen. It is a single chip so no ugly dots of light. I was very suspicious about them but they work very well and I would recommend them and they are less than $90 ea. I am building a new house, hence my investigation and plan to use them in my whole house. They fit into a 90mm hole. They are not a replacment globe it replaces the entire halogen globe and housing. PM me if you are interested. They are sold by a friend of mine so I guess I do have some affiliation. Re: LED downlights 72Sep 30, 2011 2:41 pm seriously guys, unless you go for the more expensive LED option, the general LED GU10 from ebay that take 85v - 245v is only as good as front porch or rear deck area. beam angle of 30 degree create unacceptable shadow, 45 degree beam is not wide enough for in-house application. I have tried 4w, 5w, 6w, 9w LED from ebay, I only replaced some of the CFL downlights that require instant light in laundry and front porch, for rear deck i stick with baton light + GE 14W spiral CFL globe. for 60$ or more to buy a halogen comparable LED downlight i would stick with a 15$ 18w CFL or 13w but punching more holes in the ceiling. GU10 CFL globe cost as little as 8$, buying 2 replacement globes for each downlight still work out cheaper than buying 1 LED downlight kit. Re: LED downlights 73Oct 02, 2011 10:09 am Masters has the new philips ambilight led bulbs. It is a regular Edison screw type base and puts out 850 lumens un a nice warm glow. I think they are about $70 over at masters, though street price in the us is about $40 from lowes, so I wouldn't be surprised if given the dollar and all, the price comes down once we see more distribution. my house blog: http://sugarloafdrivebuild.blogspot.com/ Re: LED downlights 74Oct 02, 2011 10:17 am Here is the amazon link to the us 110v philips bulb that is rated as 800lumens/60w equivalent. They also make a 75w equivalent http://www.amazon.com/Philips-Ambient-D ... B004IUMGV4 I Saw the 240v version of this in Melbourne at the new masters home improvement store. Hopefully when Australia gets a bit more distribution we will be able to pick them up for similar prices to what you see on amazon. my house blog: http://sugarloafdrivebuild.blogspot.com/ Re: LED downlights 76Oct 13, 2011 10:26 am Don't go to middys for brightgreen. After we got ours we found out we could've had them much cheaper. They were $30 over the recommended retail. Call brightgreen and ask who sells them. As an aside we are very happy with them. Re: LED downlights 77Oct 13, 2011 1:13 pm donnam Don't go to middys for brightgreen. Thx for the heads up. I'm at frame stage, and was about to get them from Middys. The BrightGreen website will tell you the retail outlets. As at 13 Oct 2011, they are going for $119 a pop. 13-08 Moved in 13-05 Build restart 13-04 VMIA compensation 12-08 Builder liquidation 12-03 Fixing 11-12 Lockup 11-11 Frame 11-09 Slab 11-09 Start 11-07 Contract 10-11 2K deposit 10-06 Titled land Re: LED downlights 79Oct 25, 2011 12:50 pm I just picked up an OSRAM 10W Warm White dimmable GU10 from bunnings for $26! I had a couple from EcoLightUp (8W and 6W) and wasn't too impressed. The light output was OK, but the light was a little bit on the greenish side. Will have to get home now and try out the OSRAM, but it looks good so far Re: LED downlights 80Oct 25, 2011 6:14 pm MattyT I just picked up an OSRAM 10W Warm White dimmable GU10 from bunnings for $26! I had a couple from EcoLightUp (8W and 6W) and wasn't too impressed. The light output was OK, but the light was a little bit on the greenish side. Will have to get home now and try out the OSRAM, but it looks good so far Not sure if these have a light output of 350 lumens or 270 lumens (both are quoted on Osram data sheets). Both these figures are a bit low for halogen replacements (800 lumens), but probably better than any CFL GU10 bulbs. I'd be interested to hear about how bright they are. Demolition August 2009, Construction Started September 2009, Completed December 2010 |