White LED lumen testing

[saabluster]

Was it wired in series or parallel? Series I can see it peaking at 2A.

This is a very good point. I wasn't even thinking series as most people just run them parallel. Now we wait for his response.

 

[Holzleim]

@Jarl:
I turned it on again and measured 3,33V at 350mA and 4,25V at 2A. So not the very best Vf values I got with my sample.

@Saabluster:
Yes, in this case I should have mentioned the die where wired in series, and so the current was 2A per die.
Was a bit astonished when you mentioned output should increase till twice 2A

 

[phantom23]

Now it's clear. Everything is fine.

 

[Jarl]

Now it's clear. Everything is fine.

When you say fine, it's 8.5W/die. That isn't fine, it's AWESOME

Can't wait for some lumen figures to be attached to that.... by my calculations, it's about 1200 lumens at 2A (350ma=220 lux=370 lumens, factor =1.68, 708*1.68=1190). Admittedly also ~35 lumens/watt at this high current, but that's the point of having a squirt mode, isn't it?

Matches fairly well with the P7 as well.

 

[nein166]

Hey jtr1962 I have a few M Bin MC-E I recently got from Amilite with an individually addressable star included free, do you feel like a visit?
If not I can throw it in the mail box.
Brian

 

[motymen]

Hello i saw this post liked it and i want to contribute

i should have a bounch of 55000 mcd (25 degrees) i got from jeledhk

could i send a couple for testing?
M

 

[saabluster]

Hello i saw this post liked it and i want to contribute

i should have a bounch of 55000 mcd (25 degrees) i got from jeledhk

could i send a couple for testing?
M

Thanks for posting in this thread. You just reminded me I forgot to send the MC-E to him. Sorry guys. I'll get right on it.

 

[Jarl]

lol, there I am seeing a post by you and thinking "yes! Finally some results!"

Take as long as you like, it's the quality that's important

 

[space]

jtr1962 : How/Have you calibrated your measuring setup? Do you have a known good reference of some sort?

I've copied your setup for measuring some of my LED's. I've a power supply with CC-regulation and I use a digital voltmeter (quite expensive Agilent 34940A + 34901A) for monitoring the Vf and current (using a shunt resistor). So I get fairly reliable readings for Vf and current but I use the cheap DealExtreme light meter for lux-measurments witch I don't believe to be to accurate.

The measurements I've done so far, seem to indicate that my calculated light outputs is roughly 30% lower than expected. (Measured some SSC P4 U-bins and some CREE XR-E R2-bins all bought at DX.) I wonder if anyone has a good suggestion for a cheep, known good reference that I could use for calibration. Is there anyone here with a calibrated setup that I can send one/some LEDs to for accurate measurement of light output?

(Will ad some photos of my setup as soon as my newly registered web domain is up and running.)


space

 

[kappa_ii]

hi
i want to built a lcd projector - and for light , insted of normal bulb , to use leds.
i find on ebay some leds , but i don`t know what color temperatur will be best and what size , cmd etc.

an exemple = this leds are good ?
and how many for equal a normal light bulb of 400-600w ?
http://cgi.ebay.com/50-PCs-10mm-0-5...hZ021QQcategoryZ66954QQtcZphotoQQcmdZViewItem

thanks anticipated for help !

 

[LEDninja]

What kind of projector are you building?

Short answer NO using LEDs are not a good idea especially the type you linked to.
They are 5 to 25 lumens each. A 400W bulb is 4000+ lumens. So you need 160 to 800 of those LEDs to match the brightness.
5mm/10mm LEDs have trouble getting rid of heat so some will die very fast if you drive them hard for maximum brightness.

SSC-P7 & Cree MCE can give you about 700-800 lumens if heatsinked properly and driven hard. But to avoid problems in long term use it might be advisable to run them no more than 350 mA per die or 1.4A at 3.6V (the MCE can also do 700 mA at 7.2V or 350 mA) giving you ~440 lumens. You still need 9 or 10 to match a 400W bulb. An 3x3 array of LEDs will not focus well from a projectors lens.
If you can live with a dimmer projector (darkened room, small screen) you can use a single P7 or MCE or even the single die P4 or XRE (dimmer still but easier to focus / less artifacts)
Here is a sample of a commercial LED projector.
https://www.candlepowerforums.com/threads/212691

The other problem with LEDs is colour rendition.
Normal LEDs are very strong in blue with green & yellow. Purple cyan orange and red are weak. This gives it a very strong blue tint.
An incandescent bulb is weak in blue more cyan and green and strong in yellow orange and red. This gives it a very strong warm (yellow through red) tint.
Sunlight is weak in blue more cyan and strong in green yellow orange and red. This gives a neutral white tint.
There are high CRI LEDs that more closely match sunlight. The Nichia 083 used in the Sundrop for example.
https://www.candlepowerforums.com/threads/199058
There are other threads in the McGizmo subforum about that LED. Also contact McGizmo about how to get the LED.
A less expensive LED is the Cree Q2/Q3 5A. Not as wide a spectrum as the high CRI LEDs but at least have the proper amount (less) of blue.
https://www.candlepowerforums.com/threads/211450

 

[saabluster]

hi
i want to built a lcd projector - and for light , insted of normal bulb , to use leds.
i find on ebay some leds , but i don`t know what color temperatur will be best and what size , cmd etc.

an exemple = this leds are good ?
and how many for equal a normal light bulb of 400-600w ?
http://cgi.ebay.com/50-PCs-10mm-0-5...hZ021QQcategoryZ66954QQtcZphotoQQcmdZViewItem

thanks anticipated for help !

This should have been in a different thread. Do some searching and you will find other threads that are talking about LEDs in projectors and post this in there as it really does not pertain to this thread. :welcome:

 

[Gryloc]

Hello, fellows! I just wanted to be a squeaky wheel and ask about progress. I finally got my MC-Es from Cutter just before Christmas. A super busyness, as well as laziness, took me over since the holidays and I have barely participated here on the CPF. Sadly, I barely experimented with these new LEDs either! I have a feeling that many others have been super busy in the past month to do much on the CPF as well.

So, how have you been, jtr1962? Have you had the opportunity to test those P7 and P4 emitters? I am excited to see the results. saabluster, have you had the chance to send those MC-Es? I have some to send now if you are interested, jtr. I have one M10 MC-E (very white) and two J6 MC-Es (kind of pink-ish orange neutral white). They have been fired up with care lately, but have less than ten minutes of use at low current levels on each.

I plan on using one of the neutral whites in a light mod project, but I am having second thoughts after noticing the unique tint and the odd optical qualities of the MC-E (It required lots of modding to the LOP reflector and still does not have the most pleasant beam). Thanks!

Cheers,
-Tony

 

[jtr1962]

So, how have you been, jtr1962? Have you had the opportunity to test those P7 and P4 emitters? I am excited to see the results. saabluster, have you had the chance to send those MC-Es? I have some to send now if you are interested, jtr. I have one M10 MC-E (very white) and two J6 MC-Es (kind of pink-ish orange neutral white). They have been fired up with care lately, but have less than ten minutes of use at low current levels on each.

Since you asked the last month has been horrible. In late November my mom got the flu. Sick in bed for a week and then symptomatic for the next three. On December 12 I got it. I guess sooner or later it had to happen living in the same house. A week in bed for me, and only now are most of the symptoms past. Actually this is the sickest I've even been in my life. I still feel weak, and my first bike ride in 3 weeks yesterday showed how much conditioning I lost. The only good part is my mom and I weren't sick at the same time, so each was able to care for the sick party and do the shopping. But the bottom line is between taking care of my mom, then getting sick myself, the last month was a loss.

It's best to wait until I test what you already sent me before sending me anything else. Besides your LEDs, I'm also be testing some Cree 5mm's which Holepuncher sent me. It looks like rain tomorrow. Maybe I'll stay in and devote the day to testing. It'll be a nice change of pace to being sick in bed.

 

[LED_Thrift]

Glad to hear you're on the upswing. Thanks again for the great work you've done here. I hope you have a great year.

 

[jtr1962]

I added the Cree 503B and cece718 3mm flat top white to the first post. Here is a repost of the results:

Cree C503B-WAN-CCACB231 5mm white (acquired January 2009)

CPF member Holepuncher sent me 3 samples of this LED for testing. These are Cree's brightest commercially available 5mm whites. The results were 26.9, 26.2, and 25.4 cd at 20 mA. These are speced for 23,500 to 32,900 mcd according to the datasheet, so the average of 26.17 cd is well within spec, although on the low side. Average beam angle was 15.1°, dead on the specified value of 15°. Color temperature was around 6500K, and the beam was extremely smooth. Average efficiency of the three samples was an excellent 79.2 lm/W at 20 mA. At 100 mA efficiency drops to 31.5 lm/W. Average output was 4.93 lumens at 20 mA, and average Vf was a low 3.11V. Corresponding figures at 100 mA were 12.36 lumens and 3.92V. Consistency between samples was great-outputs were 4.67, 5.16, and 4.97 lumens at 20 mA. Output doesn't scale as well with current as some other recent 5mm LEDs I've seen, but it's not horrible, either. Overall these appear to be great LEDs, and could be even better if they used Cree's best dice. Just doing some rough assumptions regarding phosphor conversion efficiency of 80% and package efficiency of 80%, I've calculated that these are using blue dice with an output of about 24 mW @ 20 mA. Cree's best dice produce 33 to 35 mW. This would produce a white LED of 110 to 115 lm/W, perhaps even as high as 125 lm/W in a wide-angle package.

cece718 6000 mcd flat top 3mm white (acquired January 2009)

I purchased 100 of these for use in model railroading lighting applications. These are the flat top 3mm LEDs sold on eBay by seller cece718. Color temperature is around 7000K, and the beam is very smooth. I knew these couldn't come anywhere close to their 6000 mcd spec given their wide angle. I measured 800 mcd at 20 mA. Output was 3.49 lumens and efficiency was an OK for nowadays 54.1 lm/W. Beam angle was a very wide 129°. Output doesn't increase much with current, and levels off at 5.91 lumens at 60 mA. This isn't surprising given the poorer thermal properties of the 3mm package, and in service I doubt I would run these LEDs over 10 mA. Overall, these LEDs aren't bad given their price. In fact, I was pleasantly surprised they performed as well as they did. It was only a few years ago that only the best LEDs managed 50 or 60 lm/W. Nowadays most commodity LEDs seem to reach that mark.

 

[jtr1962]

Gryloc sent me a pair of DSW0J Seoul Semiconductor P7s and one each of U2SW0H and U2SV0H P4s. One of the P7s appeared defective (it didn't light up until driven at around 1 amp, and output was reduced compared to the good one). Here are the results of the good P7:

Output at 2800 mA is only a little lower than the speced value of 800 to 900 lumens. Note that I was able to reach nearly 1200 lumens at 7 amps. Unlike the last P7 test, this time around I always had a fan cooling the heat sink in order to maximize output.

Here are the results of the U2SW0H:

Here are the results of the U2SV0H:

The U2 bin is speced for 100 to 118.5 lumens. Both samples met this spec, although on the low side. Although not quite in the same league as Cree's best XR-E bins, these are close enough that most couldn't tell the difference by eye. Note that the efficiency of these really falls off above 1500 mA, and not much past 1500 mA the output levels off. At 2000 mA the output is quite a bit less, and the LEDs also turn an angry blue color. Hence, I only drove them a few seconds at that level.

 

[jtr1962]

jtr1962 : How/Have you calibrated your measuring setup? Do you have a known good reference of some sort?

I've copied your setup for measuring some of my LED's. I've a power supply with CC-regulation and I use a digital voltmeter (quite expensive Agilent 34940A + 34901A) for monitoring the Vf and current (using a shunt resistor). So I get fairly reliable readings for Vf and current but I use the cheap DealExtreme light meter for lux-measurments witch I don't believe to be to accurate.

The measurements I've done so far, seem to indicate that my calculated light outputs is roughly 30% lower than expected. (Measured some SSC P4 U-bins and some CREE XR-E R2-bins all bought at DX.) I wonder if anyone has a good suggestion for a cheep, known good reference that I could use for calibration. Is there anyone here with a calibrated setup that I can send one/some LEDs to for accurate measurement of light output?

I checked my lightmeter in Silverfox's lightmeter benchmark tests and now apply a correction factor (x1.116) to my calculations. Also, a while back I measured some samples sent to me by evan9162. My results agreed with his to within a few percent despite using different meters and setups. Your results are probably off due to your light meter not giving accurate absolute measurements. I don't know if the lightmeter benchmark testing is still ongoing, but that's as good a way as any to calibrate your meter against known standards. Here's the link to the thread.

 

[jtr1962]

Glad to hear you're on the upswing. Thanks again for the great work you've done here. I hope you have a great year.

Thanks for the warm wishes. :thumbsup: I certainly hope 2009 is better than 2008 for everyone.

 

[Holepuncher]

Nice work jtr1962. Dont know how you manage it all. I guess my nichias are the 27,000 mcd ones. I was wondering if you could explain something about your test setup. It would seem to me, at a distance of 1 meter, much of the light from the led would miss the sensor of your light meter. I know it works because all your numbers are in the ballpark.