# 10mm 350.000mcd 1W LED?



## HansV (Mar 9, 2010)

I just ordered this LED's form ebay:
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=250559376379&ssPageName=ADME:B:EOIBSA:GB:1123
Have anyone here tested them? According to spec, they should give about 130 lumen. If that is correct, it should be pretty good.
I want to use it to modify a flashlight, but will the angle be too wide? Just wondering, I am a newbee in this game.

I was also wondering how to adept it for use in 12V lights in my cabbin, where wy mostly have lamps with standard small screew sockets and converters for small plug-in halogen lamps. They will fit nice in the socket, byt I need to regulate the voltage/current. Maybe I just can make a regulator that fits on the power plug, or mounted on the cable? Hmmm.....


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## Lynx_Arc (Mar 9, 2010)

I recommend getting some previous generation crees, luxeon rebels, luxeon, or Seoul P4s as 10mm probably won't even do 40 lumens and 300 ma sounds a bit much for a non heatsinked LED IMO. I think you will be dissapointed.


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## HansV (Mar 9, 2010)

Do you think the specified data is incorrect? 350.000mcd and 40deg should equal about 130 lumen. 
No way to tell if this is correct, because they to not specifies the manufacturere or part#. It is genuine "Chinese Export"
Anyway, I will not be running them at maximum current, so the temperature should not be a problem.
I will always find use for them, no problem when they only cost 2$ each.


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## JohnR66 (Mar 9, 2010)

Run, don't walk away from this garbage. I tested a few LEDs from JELEDHK and they overstated the intensity and they faded in brightness in a short time.

I have not tested these specifically, but the medium power LEDs I tested would die in a few days if operated anywhere near the max rated current. This package is insufficient (IMO) at dissipating the heat generated by 300ma current.


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## HansV (Mar 9, 2010)

OK. Thanks for the answers. 
We shall see the outcome of this when I recive the LED's and drivers for MR16 lamp sockets I have ordered.
I will test with the drivers modified for lower current. Theese LEDs should do the trick, even if thye are noe up to spec.


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## vaska (Mar 9, 2010)

JohnR66 said:


> Run, don't walk away from this garbage.



+1


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## Lynx_Arc (Mar 9, 2010)

HansV said:


> Do you think the specified data is incorrect? 350.000mcd and 40deg should equal about 130 lumen.
> No way to tell if this is correct, because they to not specifies the manufacturere or part#. It is genuine "Chinese Export"
> Anyway, I will not be running them at maximum current, so the temperature should not be a problem.
> I will always find use for them, no problem when they only cost 2$ each.



you could probably advertise for "pulls" or castoffs of high output LEDs from people upgrading lights for a few dollars and have some emitters/stars that would smoke those big time. anything in that plastic type non heatsinked body is not capable of outputs exceeding about half a watt because LEDs with that much power input (~300ma) require heatsinking or they fry. I would say even a 5mm nichia GS would smoke it in output after about 100 hours of runtime.


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## HansV (Mar 10, 2010)

*Recommendation 1W star?*

What kind of "star" do you recomend for me, then?
Is any of the 1W, 70-100lm "stars" on ebay any good? 
Is there much to gain with a more expensive LED?
Will I get more or less light by using a 3W LED and feeding it 1W power?

I have a small flashlight with a 1W LED and a rechargable 3.7V 750mAh lithium battery that I want to modify. I will keep it on 1W, because that's about what this battery can handle. I think it is connected directly to the battery, and the current is limited by the internal resistance in the battery. But I could be wrong, because I have not managed to open it up yet.

A lots of questions, but that is part of getting started with a new hobby. 
I have also rigged up a small solar panel I can use to measure light intensety to compair different LED setups. That is a nice tool when trying to make it better. One of the advantages of being a collector and electronics engineer it that I have a lot of stuff laying around and could build about anything from it

Thanks again for guiding me to the right path with your wise answers.


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## Lynx_Arc (Mar 10, 2010)

*Re: Recommendation 1W star?*

without some sort of reference, it is possible your light already has one of those cheap no brand LEDs you are looking at on ebay. Don't be fooled by numbers when no brands and bin numbers are attached to them because they can make up whatever they want on description there. As far as the light being only able to handle a 1 watt LED, I would say it probably could handle something like 4-6 watts into an LED using a lithium ion battery that is but depends on the circuit or driver involved if there is one as some have drivers that limit current and some have resisters. If you want to upgrade it I would suggest looking into a high bin LED of similar focal design to your light. Basically you are asking for advice on how to upgrade something that we cannot tell what you have in the first place. If you have a 80 lumen LED in it and put a 120 lumen LED it may not be a lot of difference but a 200 lumen LED would possibly double the output and be noticeable but could cost you a good amount of the price of a light with such high bin LED already in it.


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## alpg88 (Mar 10, 2010)

something does sound wrong, i bet it is the same leds that guy i buy leds from sells, but, in his data sheet forward current of 120ma, and it is 40* they look identical, and i,m pretty sure they are the same, made at the same plant. 

i have 10mm 0.5w leds that were rated at 280000mcd, i doubt the rating is right thou, i use 5 -10mm leds in my builds, for flood, 40* 10mm gives good flood.
mine were rated at 100ma, i run them at about 80, this way they are still very bright, no heat issues, and will most likely last a while.
the light in my avatar has 12 of those 10mm led, i can't complain, they work just fine, if you do it the right way.


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## Lynx_Arc (Mar 10, 2010)

I have heard too many bad reviews of 5mm and 10mm LEDs from all but cree and nichia on CPF. most have suffered from fast deterioration in operation even at spec, while almost all suffer from tint issues unlike your high power LEDs which tend to be closer to white and run 10k hours or more even overdriven and put out nice flood with no splotchiness the plastic lens (optics) built into most of those LEDs contain.


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## Evilsizer (Mar 11, 2010)

well i ordered a 256K MCD/40 degree beam angle/7k color temp, 10mm LED for $3.49. this one here, there was one description that stated they only get LED's from liteon,oshram,Agilen,HP,stanly and one other. i cant find the one led description where they state this ATM.

Maybe im looking at things wrong with that LED 256kMCD, i tested mA at different voltages. it can pull more then [email protected], my supply source was 3 AAA in series with 25ohm resistor to control voltage to the led. at 3.3v it was barely warm on the lead(anode, i think) above 3.3v it got hotter pulling more current. i still havent learned all the lingo used for this stuff here. i assumed when they said forward current was 100mA that is what it would pull thru the voltage range they listed for it. i guess that means i should be using a variable voltage regulator with 100mA max current output.


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## Lynx_Arc (Mar 11, 2010)

if you look at the description that is essentially 5 5mm LEDs put into one 10mm case as 5x20ma=100ma. unless you need the throw you could just buy 5 5mm LEDs and get the same output with perhaps less heat issues when driving them hard due to the dies being separated. If you could get an old luxeon 1 star you would realize that the 5 and 10mm leds like this are very low tech now as a first generation luxeon can be driven at 350ma and a lux 3 at 500-700ma easily


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## Evilsizer (Mar 11, 2010)

Lynx_Arc said:


> if you look at the description that is essentially 5 5mm LEDs put into one 10mm case as 5x20ma=100ma. unless you need the throw you could just buy 5 5mm LEDs and get the same output with perhaps less heat issues when driving them hard due to the dies being separated. If you could get an old luxeon 1 star you would realize that the 5 and 10mm leds like this are very low tech now as a first generation luxeon can be driven at 350ma and a lux 3 at 500-700ma easily


i didnt know it was considered low tech and i know the cree's and luxeons are better. like you said they also require more current as well. i just bought a few led's to play with. though the 256k one i bought, i bought with the intention of trying to make a long lasting headlight. even if light output was lower i could get it to last much longer. Are there any lower current Luxeon or Crees? im just not sure where to look for those if they exist.


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## vaska (Mar 12, 2010)

Evilsizer said:


> Are there any lower current Luxeon or Crees? im just not sure where to look for those if they exist.



You don't need to look for some special low-current diodes because powerful diodes driven at lower current show outstanding light output. For instance, Cree XP-G R5 has efficiency of 91 lm/W at maximum 1.5 A current (5 W power consumption), 138 lm/W efficiency at 350 mA current (1.05 W consumption) and phenomenal 160 lm/W at 60 mA (160 mW consumption).


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## Lynx_Arc (Mar 12, 2010)

Evilsizer said:


> i didnt know it was considered low tech and i know the cree's and luxeons are better. like you said they also require more current as well. i just bought a few led's to play with. though the 256k one i bought, i bought with the intention of trying to make a long lasting headlight. even if light output was lower i could get it to last much longer. Are there any lower current Luxeon or Crees? im just not sure where to look for those if they exist.


like vaska said, the advantage of the latest bins of crees etc is they can be more efficent at the lowest output levels. a single cree properly heatsinked can handle up to 5 watts of power and operate well from 40ma up to 1.5 amps while a 10mm LED operates at 5ma to 150ma perhaps. you could run a cree on less than 40ma I have a cree XRE Q5 bin in a modded sylvania lantern at 25ma that is about 50% brighter than a 5mm LED driven at ~30ma.


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## bstrickler (Mar 12, 2010)

Lynx_Arc said:


> you could run a cree on less than 40ma I have a cree XRE Q5 bin in a modded sylvania lantern at 25ma that is about 50% brighter than a 5mm LED driven at ~30ma.




In my Quark AA^2 tactical, it's brighter @ 10 ma than one of my keychain lights that are direct drive with 2 2016 coin cells (havent checked the current going to it, yet, though).


Personally, I would say, get an XP-G R5, and drive it at the same power, and you'll be MUCH happier. Excellent quality LED's at a fair price. They'll last much longer than the 10mm ones, especially since you still need to figure out how to effectively heatsink the 10mm LED's, and with those tiny legs, it won't be an easy project.

~Brian


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## HansV (Mar 12, 2010)

I have ordered a XP-G R5 for this project now, after reading this forum and Cree datasheets. It even seems that the XP-G delivers up to spec, and that is quite impressing. Almost 140lm at 1W and efficiency up to 160lm/W at lower current. Maximum output up to 550lm in the 5W range! 
Ref. Cree datasheet and this test: https://www.candlepowerforums.com/posts/2990597&postcount=303

I think I still will find use for the 10mm LEDs, but not in a flashlight.
Thanks again for enlightening me!


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## HansV (Mar 12, 2010)

LED's need to have a regulated current, not a fixed voltage. The voltage will change from one LED to another, and is also very temperature dependent. Becuase of this, you never know what current/wattage you will get at a specific voltage. The voltage drops when it gets hot. With a fixed voltage, you can get a current rush (voltage drops, current increses, voltage drops, current increses, LED breaks).
You need either a active current regulator/limiter that regulates the current using semiconductors or a passive current limiter using a series resistor. Flashlighs where the battery is connected directly to the LED uses the internal resistance in the battery as current limiter.
I hope this explains it. Base case it that you either use a series resistor or by a LED driver. They are cheep and saves you a lot of hassel. Just make sure to get one that fits your LED and battery configuration.



Evilsizer said:


> well i ordered a 256K MCD/40 degree beam angle/7k color temp, 10mm LED for $3.49. this one here, there was one description that stated they only get LED's from liteon,oshram,Agilen,HP,stanly and one other. i cant find the one led description where they state this ATM.
> 
> Maybe im looking at things wrong with that LED 256kMCD, i tested mA at different voltages. it can pull more then [email protected], my supply source was 3 AAA in series with 25ohm resistor to control voltage to the led. at 3.3v it was barely warm on the lead(anode, i think) above 3.3v it got hotter pulling more current. i still havent learned all the lingo used for this stuff here. i assumed when they said forward current was 100mA that is what it would pull thru the voltage range they listed for it. i guess that means i should be using a variable voltage regulator with 100mA max current output.


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## Evilsizer (Mar 12, 2010)

HansV said:


> LED's need to have a regulated current, not a fixed voltage. The voltage will change from one LED to another, and is also very temperature dependent. Becuase of this, you never know what current/wattage you will get at a specific voltage. The voltage drops when it gets hot. With a fixed voltage, you can get a current rush (voltage drops, current increses, voltage drops, current increses, LED breaks).
> You need either a active current regulator/limiter that regulates the current using semiconductors or a passive current limiter using a series resistor. Flashlighs where the battery is cunnected directly to the LED uses the internal resistance in the battery as current limiter.
> I hope this explains it. Base case it that you either use a series resistor or by a LED driver. They are cheep and saves you a lot of hassel. Just make sure to get one that fits your LED and battery configuration.


ok well that doesnt support what i have for set [email protected] while not the best DMM it is a $29 from RS. i was measuring current going from the out of the reo to thru the DMM to the LED. as the voltage drops the current the 10mm led uses was less. as i increased the voltage the current requirement got higher. while not the 256k MCD LED, the 200k MCD LED. i remember from basic electronics class always being told. if the device gets higher voltage it pulls less current, so im a bit confused how this case is the opposite.

As the Voltage to mA numbers are as follows
200k MCD LED
3.00v=52.3mA
3.10v=66.5mA
3.20v=92.7mA
3.30v=121.1mA
3.40v=154.4mA
was as far as i tested, since i saw the increasing current on the small mA AAA's. i figured i would stop as it would be skewed since i had been toying with it for a bit. *note* 3 AAA's unloaded voltage read 4.8v then tied to a resistor in series (reo) 25ohms/5watt.

here in the next week or so i should have a lab grade regulated voltage/regulated current power supply to play with.


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## Lynx_Arc (Mar 12, 2010)

Evilsizer said:


> i remember from basic electronics class always being told. if the device gets higher voltage it pulls less current, so im a bit confused how this case is the opposite.


actually the opposite is true most devices pull more current at higher voltage unless they are regulated output either voltage or current they are considered a resistive load for the sake of calculation and ohms law states E=IR so the if the load resistance (R) stays constant as the voltage (E) increases so will the current (I) to balance the equation.


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## HansV (Mar 12, 2010)

If the power consumption is constant, you will have less current when you increase the voltage. A switch mode(boost/buck) LED driver will work like this, because the loss in the regulator is't affected much by the input voltage.
BUT, if you have a linear regulator, the input current is constant when the LED power is fixed. This makes the input power increase linear to the input voltage accordeing to P=U*I
If you regulate with a series resistor, input power will increase even more, because both the current and the voltage increases.

Does this answer your question?
If efficiancy is not a problem, you can use a series resistor on the LED and connect it to a fixed power supply. Deside what current you need, fint the LED voltage for this current and calculate the resistance using ohm's law:
R=(Usupply-Uled)/Iled. 
The power in the resisor will be:
Pres=(Usupply-Uled)*Iled
The LED power is of cause:
Pled=Uled*Iled

This solution does burn lot of power in the resistor for high power LEDs, but is fine for low power when efficiance is not critical. Else you can just get or build a switched LED driver.
Your solution with a 25ohm resistor will limit the current to about 60mA (4.8-3.3)/25 maximum, but you will probabily get less. The batteries also have a internal resistance, that causes the output voltage to drop when you load them. This comes in series with the 25ohm reistance.
Ii you want 100mA for this LED, a 10ohm resistor should do fine with 3xAAA batteries. You can also try to connect the LED without a resistor and emasure the current, but it probably will be too high.


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## HansV (Mar 12, 2010)

I did'n realize this was a special LED, with several emitters inside. That will make the driving a little less stright forward. But my quess is that you still want to control the current, to awoid damaging the LED. To get 3.5V it seems that you will need close to 200mA, and that could be too much since the LED is spec.ed for 100mA. At least it will get warm and need cooling.



Evilsizer said:


> ok well that doesnt support what i have for set [email protected] while not the best DMM it is a $29 from RS. i was measuring current going from the out of the reo to thru the DMM to the LED. as the voltage drops the current the 10mm led uses was less. as i increased the voltage the current requirement got higher. while not the 256k MCD LED, the 200k MCD LED. i remember from basic electronics class always being told. if the device gets higher voltage it pulls less current, so im a bit confused how this case is the opposite.
> 
> As the Voltage to mA numbers are as follows
> 200k MCD LED
> ...


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## alpg88 (Mar 12, 2010)

edit..


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## HansV (Mar 17, 2010)

Now I got the 10mm LED's, and you are correct that they are overrated. I think the put on an extra 0 zero in the end
Anyway, it gives nice warm light and will fit perfectly in G4 sockets spotlights in the cabin as a replacement of power hungry 10W halogen bulbs. I will just add a cheap driver I got from ebay.


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## Lynx_Arc (Mar 17, 2010)

HansV said:


> Now I got the 10mm LED's, and you are correct that they are overrated. I think the put on an extra 0 zero in the end
> Anyway, it gives nice warm light and will fit perfectly in G4 sockets spotlights in the cabin as a replacement of power hungry 10W halogen bulbs. I will just add a cheap driver I got from ebay.



you may find that driving them at spec the life is a lot less than rated


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## HansV (Mar 17, 2010)

I think I will drive them below spec, and life is not critial as it only will be used for some hours during some of the weekends.
But I see your point. 
The LED will actualle will get some cooling from the large pin flange, but propably not enough for 1W continues power without a heat sink. I will measure the temperature in the plastic and pins when running it on 1W and post it here. The die temperature will of cause be higher, but it looks like it has quite good heat transfer form the die to the anode pin that is made of 1x4mm brass. This could of cause be soldered to a small heat sink for better cooling, maybe I will make a round 1mm brass plate for this? I will just have to find the maximum diameter that will fit in the spot light socket. That would look nice too

Edit:
Measurements 350mA, 3.2V, no cooling:
Temperature, plastic housing: 65 degrees C
Temperature, Anode pin: 75 degrees C

Measurements 350mA, 3.2V, cooling with a 15mm brass circle soldered to the anode:
Temperature, plastic housing: 60 degrees C
Temperature, cathode pin: 70 degrees C

Apperently it will need cooling with this current! A 15mm circular brass plate is to small to do much good, but would have worked if it was larger because it has good heat transfer from the anode.
I will try to get down to 50 degrees C on the cathode as a goal, but then I will ned to reduce the current.

Measurements 250mA, 3.0V, cooling with a 15mm brass circle soldered to the anode:
Temperature, plastic housing: 45degrees C
Temperature, cathode pin: 55 degrees C

This looks better, I think I will be using 200-250mA


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