I realized I can get a good estimate of the total output (lumens) from my measurements with a bit of math trickery. Because the radiation from the LED is distributed in angle in a known pattern (it is very close to a Lambertian surface), I can derive the total output if I know the luminous intensity directly above the LED. I did this calculation when I was trying to get an absolute value of the output from a ceiling bounce test.
I will outline it here:
Just multiply the luminous intensity (in cd) above the LED by pi to get the total output in lumens.
As a sanity check I will compare the output of the XPL V6 1A using this method with the XPL V6 2C that djozz measured, at 4.0A. LEDs with dome are also very close to Lambertian surfaces so this should be a good estimate. From here, the luminous intensity above the XPL V6 1A with dome at 4A was 522.7cd. Multiplied by pi we get 1642 lumens, which is close to the ~1575 lumens that djozz measured at 4A.
I added the plot with total output for the XHP35 to the OP.
2600 lumens from an XHP35 HI? That’s more than I was expecting. Very nice results. SO I could theoretically get 7000 lumens plus 300+kcd if I mod my SP03.
Right PD, the Thrunite TN42 makes 2643 lumens out the front in my lightbox. I have a modified L2 with XHP-35 making 2986 lumens at 3.17A. So, as long as the 3 in your SP-03 are still able to pull a current in the 2.6A range, you should see nice results. And amazing throw as well, probably in the 320-330Kcd range unless I miss my quess.
Nice work with that figuring EasyB, seems to correlate pretty well.
When you said to multiply by pi I figured I was in trouble, ate the last of the pumpkin pie just last night…
I’ve got one doing 2.8A in a MaxToch Shooter 2X, another in a MaxToch SN50 doing about 2.83A and the one in the L2 doing 3.13A. These are all using the LD-2 modified to work on 4 cells. The big MaxToch is using 4 18500’s, the Shooter 2X is using 4 18650’s. The L2 of course is using 4 of the 26350’s.
The TN42 is running on 2S2P Samsung 30Q’s. Been meaning to test it and see if it makes the same numbers on a lesser cell…
Edit: the one doing 2900 started out domed and I sliced it. The Shooter 2X is an HI variant and the SN50 is an HI as well.
I just tested my L2 in the box, 2349 with the little 26350’s at 4.17V well rested. So yeah, about a 600 lumen’s loss in the end. But over 300Kcd so it’s still very viable.
Thanks for measuring again. I think you misremembered the throw number though. You said it was around 208kcd.
The die luminance is sensitive to the thickness of silicone left after slicing, so maybe with a HI emitter or a closer slice it could get up pretty close to 300kcd in the L2.
Yeah well, doing good to remember my own name after nights like last night. With so many lights its tough to keep all the particulars separated. I know my Shooter 2X got about 322Kcd, very close to what it was as a de-domed XM-L2. Why on earth would the larger L2 be less throwy? Now I gotta go get a new reading on that too.
Yep, 206.75Kcd as of 2 minutes ago. The Shooter 2X has a larger diameter and deeper reflector, as well as being powered by 4 Samsung 30Q cells instead of the short 26350’s.
Are those 26350’s sagging under 2.6amps? I think it must be more about the reflector and focus of the Shooter than it is the cells. Or of course the emitter itself. Are they both HI’s or is one sliced?
L2 with dedomed XPL V6 1A can reach 280Kcd. Based on my measurements, the XHP35 HI could reach ~93% of that. If the dome slice is not very close, that could take away an additional 20% to make ~208Kcd.
Nice testing, I have an XHP35 on order to test myself. I want to see if you can drive it with a PWM from 4S cells and how that compares to a constant current in output.
The Texas buck driver is nearly done but frankly it is simply going to be too expensive for all but the most dedicated setups. So back to using a liner driver. Maybe have to rethink the whole op-amp thing.
I got the opportunity recently to mod a Lummi Short Orb. The original driver was non-functional and, if still available (which it isn’t) would be $50 for the driver itself. This little Lummi now has a 12mm FET driver with ramping firmware making from 10 to 1911 lumens.
Yeah, I am glad I decided to go ahead with the Texas Buck but it is looking like it will be $15 in parts alone all said and done. Not out of this world but 2-3X more expensive then most other drivers we use.
There is the possibility that price can be reduced some but not drastically while keeping the high current ability.
So that comes back to the Texas Avenger or an Op-Amp setup.