djozz tests

Nice Collection
Could bot find the crashtest of xml and xpg in your List:

These measurements are always the first place I look to get an estimate of what’s possible and expected for anything light-related. Way more useful than the official specs.

Very helpful reviews.

By your chart for the xp-l vs xm-l about 950ma will produce 500 lumen and 3000ma will produce 1000 lumen. Suppose you take two of these leds wire them in series then the same for another pair. Now wire the two series pairs in parralel. The overall impeadence should be the same as a single led. Now drive this at 2000ma, to give each leg 1000ma. What would the voltage be? I assume 1/2 so the total voltage would have tobbe doubled.
Would you not now get 2000 lumen at only 2/3 the current for a single producing only 1000 lumen? as the wattage is i suared x r. Am I not now producing a lot more lumens for a lower power consumption. Or is there a flaw in my reasoning?

Well, a single highest-bin XM-L2 or XP-L will produce around 1200 (or more) lumens at 3000ma. Small difference from what you’re saying, but anyway. The biggest flaw in your math is that you’re failing to double the voltage for two emitters in series. So, in reality, the difference from four emitters connected 2S2P compared to one emitter is:

XM-L2 4X = ~2000lm from 6.04V x 2.0A for ~165 lm/w
XM-L2 1X = ~1200lm from 3.43V x 3.0A for ~116 lm/w

XP-L 4X = ~2085lm from 6.12V x 2.0A for ~170 lm/w
XP-L 1X= ~1250lm from 3.46V x 3.0A for ~120 lm/w

(These are rough calculations based on ratings in Cree PCT)

Still a good bit more efficient, but at the cost of 4X the emitters and double the voltage.

Edit: Just a quick addendum. If this math is correct, you would be using (a little less than) 4/3 the total wattage and getting 5/3 the total output when using 4X the emitters.

great info here, thank you djozz . losses on aspherics is very interesting for me. aware by the fact of loses of light, i like to build double aspherical systems almost always. its nice to have an big spot in a zoomie with an performance as high as 70% of total light output or even more. i wish i could have a big sphere sometime to measure my light.

Thanks you very much djozz for your invaluable contribution to our community.

A video of djozz reflowing mutiple leds on a single MCPCB

This is a good question…I’m trying to decide between the 219C 5000k and the XP-L 4000k V2. The 219C seems to still have the higher CRI (83 vs 75) but it might be negligible. The 4000k’s tint is quite nice but I’m not really sure which one is more efficient or has more overall output.

The XP-L HI likely has higher output and better throw. But do you prefer 4000K or 5000K? Have you compared the two color temperatures in person?

Me, I don’t like 4000K. It looks yellow to me, even at 93CRI. Many people really like it though.

I kinda prefer around a 4500kish tint tbh. I haven’t seen either in person, but I do have some BLF-348s on order. The 4000k XP-L HI shots I’ve seen online I actually do like…doesn’t seem yellow….maybe more of a 4400kish look.

I guess you’re right though…in the end the CRIs are pretty similar in these so it would just come down to the tint I prefer.

Djozz I could have sworn you had tested an XHP35. Am I wrong?

Yeah, you shouldn’t swear.
JK :smiley: I have no idea

Hey whizz I love your data. Have you ever tested the xhp 35 hi?

I have a few tests of the XHP35 in my sig, not sure if Djozz ever tested them.

No, I haven’t. By the time I could order them there wete many people with data on the XHP35, especially the good test by Texas_Ace.
The Hi version would have a bit less output, but the voltage data and curve shape should be similar.

I looked and didn’t see it Texas, thank you.

Try this one: XHP35 output and death test + PWM efficiency test by Texas_Ace

Hey djozz,

Do you have any interest in putting line breaks in your OP to make the list of test, well… a list, instead of a paragraph?

I find myself coming back here all the time because it is such a good reference, but the formatting of the OP is a bit difficult to find the particular test I’m looking for.

Just a thought.

Hi sac02, I’m glad that you find my tests useful :slight_smile: .

I like the compactness of the OP, a list would stretch it out enormously. But if the general opinion is that a list is more handy, I can change that of course.