archer6817j
Enlightened
Hi folks, I've been debating a hard decision. Long story short, I've decided to downgrade the "listed" output on the MCE version to 430 lumens instead of 500. Now before you get too excited, every light I've sent out so far has actually been over 500 lumens.
So why downgrade my listed output? Because I'm the type who under promises and over delivers. I also discovered why it's a bad idea to report the output of every custom light I make: variability in LED manufacturing. According to ANSI standards I could take 5 lights and average the measurement and report that average for every light. If I averaged every MCE light I've sold so far it would be about 515 lumens. I should have taken the "easy out" and gone with the ANSI average...but I also want you to know exactly what you are getting when you buy one of my custom lights. It's something that sets my lights apart.
Here's the actual problem: For MCE's the bin range for output is a 60 lumen spread according to the Cree spec sheet. That's a pretty wide range. The XML only has a 20 lumen spread per bin.
Anyway, this means within "M" bin (statistically speaking it's a bell curve) you'll get a few low performers at 430 lumens, most will average "in the middle" around 465 lumens, and a few will be superstars over 500 lumens.
I've ordered 3 batches of LEDs, all with exactly the same part/bin numbers and I've seen pretty wide results:
1) The fist batch of LED's I bought (I only have 2 left) were from the superstar end. My worst light was 507 lumens OTF and my best was 540 lumens OTF.
2) I ordered a "test batch" of LEDs from a domestic authorized Cree dealer. Sadly these were from the low performing end. I've been seeing OTF readings around 430-450 lumens.
3) I ordered a third batch and these are around 450-480 lumens OTF.
Conclusions:
1) I decided to make my "listed" lumen rating based on the lowest possible output I expect to see...430. Basically I can't afford to order 100 LEDs and not be able to send them out because they don't meet my advertised spec.
2) I'm not going to put the low performing batch into lights purchased by CPF members. I only got 25 of these and I'll put them in non-CPF lights. They will still met my new 430 lumens spec but you guys want the good stuff...right?
3) For the time being I'll be using the "average" performing batch in my CPF lights. Fingers crossed, these should be no less than 450 lumens.
4) I'm talking with cree about how I can try to get MCEs from the higher performing end of the bin...it may not be possible.
5) I'm still going to report the lumen output for each light. So, if you set your expectations at 430 and end up with 480...awesome right?
6) Can you tell the difference between 430 and 500 lumens? If you compared identical lights side by side, you can tell. One light at a time? Not a chance.
So why downgrade my listed output? Because I'm the type who under promises and over delivers. I also discovered why it's a bad idea to report the output of every custom light I make: variability in LED manufacturing. According to ANSI standards I could take 5 lights and average the measurement and report that average for every light. If I averaged every MCE light I've sold so far it would be about 515 lumens. I should have taken the "easy out" and gone with the ANSI average...but I also want you to know exactly what you are getting when you buy one of my custom lights. It's something that sets my lights apart.
Here's the actual problem: For MCE's the bin range for output is a 60 lumen spread according to the Cree spec sheet. That's a pretty wide range. The XML only has a 20 lumen spread per bin.
Anyway, this means within "M" bin (statistically speaking it's a bell curve) you'll get a few low performers at 430 lumens, most will average "in the middle" around 465 lumens, and a few will be superstars over 500 lumens.
I've ordered 3 batches of LEDs, all with exactly the same part/bin numbers and I've seen pretty wide results:
1) The fist batch of LED's I bought (I only have 2 left) were from the superstar end. My worst light was 507 lumens OTF and my best was 540 lumens OTF.
2) I ordered a "test batch" of LEDs from a domestic authorized Cree dealer. Sadly these were from the low performing end. I've been seeing OTF readings around 430-450 lumens.
3) I ordered a third batch and these are around 450-480 lumens OTF.
Conclusions:
1) I decided to make my "listed" lumen rating based on the lowest possible output I expect to see...430. Basically I can't afford to order 100 LEDs and not be able to send them out because they don't meet my advertised spec.
2) I'm not going to put the low performing batch into lights purchased by CPF members. I only got 25 of these and I'll put them in non-CPF lights. They will still met my new 430 lumens spec but you guys want the good stuff...right?
3) For the time being I'll be using the "average" performing batch in my CPF lights. Fingers crossed, these should be no less than 450 lumens.
4) I'm talking with cree about how I can try to get MCEs from the higher performing end of the bin...it may not be possible.
5) I'm still going to report the lumen output for each light. So, if you set your expectations at 430 and end up with 480...awesome right?
6) Can you tell the difference between 430 and 500 lumens? If you compared identical lights side by side, you can tell. One light at a time? Not a chance.
