# 50W emitter



## MikeElectrician (Oct 27, 2007)

http://www.dealextreme.com/details.dx/sku.5876 10 Watt
http://www.dealextreme.com/details.dx/sku.5848 20 Watt
http://www.dealextreme.com/details.dx/sku.5766 50 Watt

Has anybody tried using these?


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## Nereus (Oct 27, 2007)

1700 lumens at 50W means 34 lm/w which is quite low...

-N


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## Trickflow25 (Oct 27, 2007)

Its not too low right? 

Lets say a Luxeon 5 watt at a 100 Lumens thats only 20 Lumens/watt right? So 1700 Lumens at 50 W is not bad I guess? Unless I am not thinking right.... :thinking:


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## Mel_PL (Oct 27, 2007)

Trickflow25 said:


> Its not too low right?
> 
> Lets say a Luxeon 5 watt at a 100 Lumens thats only 20 Lumens/watt right? So 1700 Lumens at 50 W is not bad I guess? Unless I am not thinking right.... :thinking:



1. The numbers are true at certain (low) temeratures, it's real PITA to keep working 50W emitter below 25 degs.
2. Forget Luxeon V. Cree and SSC are close to 60 lm/W.

-- M.


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## Erasmus (Oct 27, 2007)

How to dissipate all the heat? 50W on such a small surface is a lot of heat to get away, I think active cooling with a big copper heatsink (like computer) processors is necessary. If the cooling is not sufficient the efficacy will go further down, and 35lm/W is already quite low, comparing to the Cree XR-E bin Q5 which is typically 94lm/W.


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## MikeElectrician (Oct 28, 2007)

The emitters I listed above are only about 30 - 35 lm/watt. Crees are almost twice as efficient. But how about 100 lm/watt for a 10 watt emitter?

http://www.ledsmagazine.com/press/15526


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## Erasmus (Oct 28, 2007)

MikeElectrician said:


> The emitters I listed above are only about 30 - 35 lm/watt. Crees are almost twice as efficient. ...


The 10W has an efficacy of 30lm/W, the 20W is 40lm/W and the 50W is 34 lm/W. The least powerful currently available Cree (the P4) is 71lm/W and the most powerful (Q5) reaches 94lm/W. I don't recommend the 10W, 20W and 50W emitters from DX for several reasons :
- poor efficacy
- unknown thermal resistance and maximum junction temperature of the emitter, it is really necessary to know these to ensure you provide sufficient cooling 
- no information about the manufacturer, no datasheet or anything available

The idea of making a multi-chip configuration into 1 single emitter is pretty cool though. If Cree/SSC/Lumileds would make these it would be a big hit in the market of solid state lighting I guess... 





MikeElectrician said:


> ... But how about 100 lm/watt for a 10 watt emitter?
> 
> http://www.ledsmagazine.com/press/15526


The 100lm/W is a lab result, that means that this is only achieved on prototypes which are not yet available for retail. The available 10W emitter reaches 69.12lm/W which is -at this moment- quite high for a multi-chip LED! Plus the low thermal resistance makes it easier to draw the heat away.


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## Gunner12 (Oct 28, 2007)

Well, the 20watt has been used in a mod. Here's the thread.


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## VidPro (Oct 28, 2007)

i use the "20W" ones here
https://www.candlepowerforums.com/threads/174996
but i assure you i only use them at around 10W.

they are arrays of series parellel leds, with gates that trigger offset from eachother, meaning its a bit sloppy acting electrically. its sufficient lumens to something like huge arrays of 5mm type leds, or very cheap 1W leds. 
stuff like that has no phosphor high tech layering, it does not do the phosphor trick of high lumen leds, on the other hand it probably has more phosphors in general. phosphor is just slopped over the whole array.
they are silicon type topped, and copper based, the copper bases are tinned (with some metal) , i assume to keep corrsion of the copper down.

they WERE listed at some 18Volts or something, and thay are more like 16volt type of leds 4 or 5 series gates, they can boil water  at full drive. not really but it could keep your coffee warm.

the ouput is whiter without being bluish than an incan, and outputs about 2x what a halogen light could do for the same power.


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## Mdemon (Nov 1, 2007)

I'm interested in this sort of thing because I want to replace the 35w halogen bulb with either 20w or 50w LED.

Now, heat isn't an issue because this is going into a diving torch - there will be a million tons of water keeping the thing cool! 

Reckon the 20w would be as bright as the halogen?


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## PhantomPhoton (Nov 2, 2007)

Most divers I know avoid LEDs (for primary lights) like the plague. Though most of their impressions were based on antique angry blue LEDs. I think modern tint binned LEDs will do much better. But you still are loosing CRI.
The tint of this LED would be a big factor in whether or not it will work well for diving. 
Also consider the LED is multi die so your light source has a greater area. It'll be harder to focus if you intend on using it for spot.


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## MikeRD03 (Nov 2, 2007)

Hi mdemon,



Mdemon said:


> I'm interested in this sort of thing because I want to replace the 35w halogen bulb with either 20w or 50w LED.
> Now, heat isn't an issue because this is going into a diving torch - there will be a million tons of water keeping the thing cool!



Forget about the edixon or similar emitters for building a diving lamp. They are nearly impossible to focus cause of their large die area. If u want to make a real bright diving lamp with LEDs take a look at the new OSRAM Ostar emitter.

greets,
MikeRD03


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## Mdemon (Nov 2, 2007)

PhantomPhoton said:


> Most divers I know avoid LEDs (for primary lights) like the plague. Though most of their impressions were based on antique angry blue LEDs. I think modern tint binned LEDs will do much better. But you still are loosing CRI.
> The tint of this LED would be a big factor in whether or not it will work well for diving.
> Also consider the LED is multi die so your light source has a greater area. It'll be harder to focus if you intend on using it for spot.



Hi, and thanks for your comments. Colour isn't really a problem for me. I find white LED and HID quite harsh, but it's great for photography etc. Warm LED is friendlier, but you lose the lumens...  

What I am after is something with a bright spot and a wide flood. I was thinking of adapting an existing bulb with the LED and then fitting a projector-style lens to the front of the torch, outside the front glass. I'm hoping this will focus most of the light into the center. There is no easy way of fitting a decent reflector unfortunately. 



Mike said:


> Forget about the edixon or similar emitters for building a diving lamp. They are nearly impossible to focus cause of their large die area. If u want to make a real bright diving lamp with LEDs take a look at the new OSRAM Ostar emitter.



Hi Mike,

I can't find a distributer for the Ostar yet. I have a 20w coming from DealExtreme to experiment with. I take your point about focus - I hope my comments above answer that. 

The top of the range dive torches seem to use individual LEDs, each having a hexagonal plastic lens. This allows them to interlock 6 or 12 into one lamp. I thought about doing this, but the light heads I am using are tiny and I couldn't fit many in. They usually take a 35w MR11 halogen bulb, so I have about 35mm (an inch and a bit) to play with. Not a lot of real estate...


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## Mdemon (Nov 2, 2007)

If you look at the bulb here, you'll see the size constraints!







(More details here)


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