# What ar the most efficient and (separately) cheapest LEDs available at the moment?



## LMF5000 (Sep 27, 2011)

By efficiency, I mean lumens per watt for a high power LED (the kind used for flashlights) Last time I checked itwas the CREE XM-L U2 - but has anything better been released into the market?

Secondly, which is the most cost-efficient high-power LED in terms of lumens per dollar (or euro)? I never really did much research into this, but it would be interesting to find out!


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## jasonck08 (Sep 28, 2011)

XM'L's are likely the most efficient LED's on the market and best value lumens per dollar.


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## idleprocess (Sep 30, 2011)

I hear that the bridgelux arrays offer outstanding lumens per dollar ... Just not well suited to flashlights.


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## LMF5000 (Oct 1, 2011)

idleprocess said:


> I hear that the bridgelux arrays offer outstanding lumens per dollar ... Just not well suited to flashlights.


 
I checked the prices and they're not much better than the XM-Ls. An XM-L on ebay costs about €7 and gives 1000 lumens. A 15W bridgelux is almost €30 and only gives 850 lumens.

However your post reminded me that there are cheap (ish) no-name LED arrays. Something like 5000 lumens for €25 or so.


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## IMSabbel (Oct 1, 2011)

LMF5000 said:


> I checked the prices and they're not much better than the XM-Ls. An XM-L on ebay costs about €7 and gives 1000 lumens. A 15W bridgelux is almost €30 and only gives 850 lumens.
> 
> However your post reminded me that there are cheap (ish) no-name LED arrays. Something like 5000 lumens for €25 or so.


 
Then it seems bridgelux dropped the ball there - they were about the same price back when an XP-G was >$10.


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## blasterman (Oct 1, 2011)

Dropped the ball {Bridgelux} with what may I ask? Not caring about how well their products perform in beam throw contests and instead concentrating on commercial lighting?

Bridgelux C0802 costs $8.22 at Newark and throws 800lumens at a stock 700mA. XM-L throws about 900lumens at 3amps max (maybe a tad more for the T6) and typically costs a buck or two more. XM-L and XP-G clearly have a significant efficiency lead while the Bridgelux emitters tend to lead in lumen per dollar ratios* in AC applications* not to mention they are far easier to obtain off the shelf AC drivers for.

Sorry, bad comparison.


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## idleprocess (Oct 3, 2011)

LMF5000 said:


> I checked the prices and they're not much better than the XM-Ls. An XM-L on ebay costs about €7 and gives 1000 lumens. A 15W bridgelux is almost €30 and only gives 850 lumens.
> 
> However your post reminded me that there are cheap (ish) no-name LED arrays. Something like 5000 lumens for €25 or so.



I have little confidence in sourcing materials from ebay, nor from the like of DX.

As soon as I get my head around bridgelux's product line-up, I expect to use them for future lighting projects around the house since their arrays lend themselves to far fewer components being used.


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## saabluster (Oct 4, 2011)

blasterman said:


> Dropped the ball {Bridgelux} with what may I ask? Not caring about how well their products perform in beam throw contests and instead concentrating on commercial lighting?
> 
> Bridgelux C0802 costs $8.22 at Newark and throws 800lumens at a stock 700mA. XM-L throws about 900lumens at 3amps max (maybe a tad more for the T6) and typically costs a buck or two more. XM-L and XP-G clearly have a significant efficiency lead while the Bridgelux emitters tend to lead in lumen per dollar ratios* in AC applications* not to mention they are far easier to obtain off the shelf AC drivers for.
> 
> Sorry, bad comparison.



Dropped the ball probably wasn't the best way to describe it. I don't think it was all that offensive to have deserved that type of response though. First off the OP did not ask what LED was best for AC operation. Also the 700mA for the BridgeLux you are speaking of is also at 12.7V. So I would assume then that it has 4 strings being powered at 700mA which if comparing to a single die LED would be running at 2800mA. I'm sure you are aware of this but some others viewing your quotes may not understand what's going on here. At 2800mA the XM-L T-6 would be pushing 875 lumens or up to around 937 if at the top of the bin. But the XM-L does not cost a buck or two more. Cutter has T-6 binned XM-Ls in single quantities for $6.69 which clearly bests the $8.22 BridgeLux. 

Of course we both know that a lumen for dollar ratio is far harder to figure than simply the exercise we are going through here as is all depends on application as you say. The BridgeLux can put out more total lumens by raising the current higher than the Cree can go so it may very well be you'd have to buy two XM-Ls to do the job of one BridgeLux. So hopefully the OP can see that "most cost-efficient high-power LED in terms of lumens per dollar" is not something any of us can really say here with much authority without knowing the application. :shrug:


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## LMF5000 (Oct 4, 2011)

Thanks for the replies so far. I don't have any particular application in mind. At most I would be using the LED as an emergency backup to light up the room when there's a powercut.

I've found that for high power emitters it's hard to beat HID / metal halide based on price per lumen. But then the price of their ballast pushes the cost up to more than the LED equivalent, at least for setups below 15,000 lumens or so.


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## deadrx7conv (Oct 4, 2011)

With the LED, how much does a suitable driver cost? This sometimes is also forgotten, along with shipping/handling.... and AVAILABILITY!

For an emergency backup light when you loose power, ceiling bounce a flashlight. Find a flashlight/battery combo that gives you the runtime that you need. 

Efficiency is for you to test. Most 'marketing types' are grossly overrating the LED bulbs on the market by not including the 'power wasted' by the driver/ballast/powersupply.... and light lost through lens/optics/..... It'll take 1.2w to get that 120lm from that 1w 140lm/w LED. As you can see, numbers can be manipulated by leaving out the power lost to the driver, and lumen output lost through the optics. 

You can't go wrong with ANY of the name brand LEDs. The choice is yours. Parameters are needed.

A 12v bridgelux can connect straight to a 12v battery. A 3.3v Cree will need a power wasting voltage step down buck driver to use the same battery. Which is better now? 

A 3.3v Cree can be driven directly off of 3xAAA batteries. But, that 12v Bridgelux will need that step up boost driver. Which is better now? 

Your Cree, Nichia, Luxeon, Seoul, Luminus, Bridgelux, Citizen, Sharp, LedEngin, Edison, Osram, Stanley, .... LEDs all have their pros and cons. I wouldn't simply jump on one saying its the 'cheapest' or 'most efficient' because it depends on the parameters. 

Do you want flood or spot? how bright does it need to be? How many LEDs do you want to use? What is the budget? What type of battery power is available, and its chargers? Do you want warm, neutral, cool LEDs? Is CRI important? 
What are you willing to sacrifice for cheap? 
What are you willing to sacrifice for efficient? 

XML-U2 cool, might tolerate it as a never used glovebox flashlight. I wouldn't want it lighting my room since I demand less tiring, on my old eyes, the neutral to warm LEDs, preferably 80CRI or higher.


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## LMF5000 (Oct 4, 2011)

LED drivers are really not a problem for me hehe. I have a couple of combination buck/boost and adjustable constant current supplies. I've also got an inverter so if it runs on 240VAC it would be good too! The only things I can't run are those 50 watt LED arrays that need a 35V forward voltage, but a boost converter with that power and voltage only costs about £7 on ebay . And there's always the possibility of direct drive. No chance of that with HID.

Efficiency isn't that important because I have a nice supply of old car batteries with something like 400 Ah between them 

The number one most important factor is cost. So doesn't matter what compromises have to be made elsewhere. Most rooms in the house are illuminated by 36W flourescent tubes with magnetic ballasts (about 3000 lumens). So really, any portable battery operated light that can light up the room with vaguely similar brightness for the lowest price possible, even if it means sacrificing efficiency, size, or anything else...


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## zzonbi (Oct 5, 2011)

Most efficient is Cree xte. It is blue, in white it's the xml. Cheapest, cxa2011: 4$/klm.



At 3000K 80CRI (average room light) it's good for up to 3000lm, with 110..60lm/W - if kept around 100lm/W only 1000lm really, but with a nice reserve just in case. Looks easy to mount too, solder on top, thin wires/high voltage, flat, not too small, less blinding etc.​



You're right looking for the cheapest: better leds are couple of years away, so, unless you leave the lights on a lot, it makes no economic sense getting something else for indoors. Problem is I can't find the cxa for sale without high shipping :-/


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## saabluster (Oct 6, 2011)

zzonbi said:


> Most efficient is Cree xte. It is blue, in white it's the xml.


Just FYI the white version of the XT-E is the XP-E HEW.


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## zzonbi (Oct 6, 2011)

No one should misunderstand xte and xml as versions of the same led; xte has a novel and quite different die.


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## saabluster (Oct 6, 2011)

zzonbi said:


> No one should misunderstand xte and xml as versions of the same led; xte has a novel and quite different die.



So I guess I misunderstood what you wrote. Sorry. It sounded like you were saying the XT-E had a different name in its' white version, which strangely it is does, and that that name was XM-L. I assigned the wrong ownership to "it's" when you said "in white it's the xml." Oh the joys of communication. 

It is strange that they chose to rename the LED when selling the blue version of the XP-E HEW. Then again I guess it is more strange that they even called the HEW an XP-E to begin with. Same die size yeah but vastly different structure and performance. Silly Cree.


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## LMF5000 (Oct 6, 2011)

zzonbi said:


> Problem is I can't find the cxa for sale without high shipping :-/



Ahh, now we're talking. 4000 lumens for a unit price of about €13... the problem, like you said, is that there are none for sale on ebay or DX or KD. I found some on another site with a unit price of €12.60, but to get one, the shipping would cost an additional €20! :sick2:

But to order a lot of them the shipping then becomes free.

So I wonder, seeing as to how none of them are for sale at reasonable prices... could this be a potential money making opportunity? Like for example, buy 15 of them at €13 each, and sell them online for €20 each? I think this is called "dropshipping"?

I've never sold anything online before (so far only ever been a buyer) - but does anyone reading this thread feel there's a market for cxa2011's being sold at €20 apiece (excluding shipping)? Would you yourselves consider buying items on eBay that originate from a country like Malta?

Whoever does try this is taking a considerable financial risk. Buying 15 of them means you have €200 worth of LED's lying around. And if no one buys them all that money goes down the drain (or you could make the world's fanciest floodlight hehe). Still, if they sell well that's a profit of maybe €75 once you factor in fees of whichever online site you sell on.


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## zzonbi (Oct 6, 2011)

"Oh the joys of communication." Yup, it stands for most efficient ;-)

"Same die size yeah but vastly different structure and performance." I had the same impression, in all fairness it looks like a non-lambertian source with a larger emitting area: a thick, tappered and grooved structure (remember those lab Nichias?). But it's a milestone, first?! led you can buy which makes more light than heat... at least at nominal current. Philips and Nichia are probably in the same ballpark, but arguably theirs look like soon to follow bins.

"Ahh, now we're talking. 4000 lumens for a unit price of about €13..." Actually the warm white 900..1040lm bin I'd like is around 15$ in low numbers, and max 3000lm. I wouldn't pay over 5$ extra... or else I'd just get 2 xmls instead, wait some more, or apply for a free sample 

Frankly, CFLs are hard to beat yet, so this would be more for coolness than economy


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## VegasF6 (Oct 7, 2011)

I think drop shipping means you never even take possession of the product, you just act as a middle man, sell the product and forward the money on to another company and they send it off. At least, that's what I always thought of. 

The CXA is available through Digikey, at least in the US so that probably would kill that market for ya.


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## LMF5000 (Oct 7, 2011)

VegasF6 said:


> The CXA is available through Digikey, at least in the US so that probably would kill that market for ya.



Shoot. It'd cost $15 for one LED and another $30 to ship it to Malta from digikey... though shipping comes free for orders of over $100 apparently.


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## VegasF6 (Oct 7, 2011)

Yah you have to take all that into account of course, it's no longer the cheapest $/lumen at that rate. Though a $100 order for free shipping isn't unreasonable in my opinion. Shipping is $9.00 for me. 
I am at a loss to find a Cree distributor for the island of Malta but I am sure you run into that all the time?


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## LMF5000 (Oct 8, 2011)

VegasF6 said:


> Yah you have to take all that into account of course, it's no longer the cheapest $/lumen at that rate. Though a $100 order for free shipping isn't unreasonable in my opinion. Shipping is $9.00 for me.
> I am at a loss to find a Cree distributor for the island of Malta but I am sure you run into that all the time?



Ahh, you seem to be familiar with Malta... Been here before on holiday by any chance :wave:?

There is no cree distributor, and no one who sells the kind of high-power flashlights CPF thrives on. In fact the only reason I actually learnt cree exists was because I saw some flashlights on eBay, and that's where I buy all my stuff. The closest you'll find in a shop is a cheap torch with 10 to 20 through-hole LEDs, normally powered by three or for AA or AAA cells - and for the kind of prices you'd buy an ultrafire single cell (18650) flashlight complete with an XM-L for. 

Other than that, for backup lighting during power cuts, most people buy the large cordless spotlight things (the ones with lead acid batteries and a 20 or 50 watt 12V halogen incan bulb), or the other kind with two 3ft flourescent tubes and a lead acid battery that remain plugged in to a wall socket and automatically switch on when they detect that the socket has lost power.

To be honest, I can't imagine more than say 5% of the population being interested in these kinds of things so a distributor dedicated solely to flashlights/CREE stuff would be difficult to sustain I would guess.


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