XHP-35

VOB, thanks for tackling the extended current chart. I thought we had a good LED here your chart was a 1/3 less than the product chart how ever. One hope left the High Density top bin claim about 1 1/2 times greater out put than the LED bin you tested. Gains in current I think showed the trade off max at about 1.5 amps before gain really slows down. Still 20 watts is a lot to bleed out in a conventional light design. I still would like to see a single cell driver for these voltages as we still have the XHP-50 and 70.

Excellent data VOB. Not the news we were hoping for, but hopes don't create lumens without some good hardware to back them up.

Love the copper bar in water heat sink idea for testing. Very nice.

If those numbers are correct, they’re terrible. An XP-L gets the same lumens from half the wattage. Disappointing indeed.

According to CREE PTC we should have at 50Celsius - 1178umens, 12.58Vf for XHP35 HI C4 bin.
I would not be surprised if someone else would measure more than 1178 lumens at 1A, you know hose these things are.

Thermal resistance is phenomenal for this LED 1.8C/W, a bit weird to see such weak results when overdriven.

Can you measure the exact die size (even if there are like 4 dies in there)?

Ya, I'm a little disappointed too. As mentioned my sphere is not perfectly calibrated for this function, but they are going to be close with this emitter. I tested this in a light too for lux, and also did a visual side by side, which had the XML2 as the winner as well.

In ONE test I was able to squeak out slightly higher lux with the XHP35, but it was nothing major, and the reflectors were slightly different.




Yes, as fart as lumen output I would still expect this emitter to exceed an XML2 by a slight margin ( 200-400 lumens).

If I can get my hands on a couple of the very top bin high density I would be willing to take another swing at it.

So what does this mean for Josiah?

Thank you for the data VOB :beer: I was hoping the LED would do better… :_(

What are the physical dimensions of the die of the XHP-35? Is it the same size as a XM-L2 die?

Success! :bigsmile:

Success! I fixed up the LD-2 like Neven said, put an 180KOhm sense resistor on it… mounted it to a large copper disc that then fit in my Maxtoch that came with an SST-50. (It’s unbranded, I’ll have to look up the model)

Running 4 Sanyo 18500 flat top lap pulls it does …

0.02A for 80.04 lumens
0.48A for 648.6 lumens
2.39A for 2018.25 lumens.

This is with the XHP-35. I messed up and went by the bond wires reflowing the emitter. BUZZ! Wrong answer!+ On this one, the bond wires go to the side, you have to go by the anode mark on the pads on the bottom of the LED+. I shorted it the first time, couldn’t figure it out so I searched the datasheet then double checked the physical emitter and sure enough, the first time I put the pads across the Noctigon.

Works, tickled to death, but have the 3 modes and I put moon components on it. Have a feeling there’s something I’ve forgotten…

Very nice indeed! :bigsmile: Will you be creating a build thread for this one?

Just got lux readings, mind you I didn’t bother to charge the little 18500’s first….

331.75Kcd for 1151.96M throw, and I haven’t even fine tuned the focus! This reflector has a wide base, I’m using a 20mm Noctigon at the moment, so I can’t get the reflector to sit down on the mcpcb like the HI series seems to prefer. I’ve got a ring showing from the thickness of the reflector at the emitter opening, but all in all it’s pretty amazing for this kind of die! It acts like a much smaller die surface actually. I’m impressed where I was expecting to be disappointed.

I didn’t take pics along the way or anything, went out of town today and came home to find the components I needed to modify the LD-2 had arrived in the mail, jumped on it and got it done after figuring out how to re-flow this odd emitter.

Remember DO NOT GO BY THE BOND WIRES! Reflow it according to the anode mark on the base. (Actually the thermal pad has a triangular cut out on the anode side)

Which XHP-35? HI or HD and bin?

HI, the first one’s Mouser had, they were on order and just came in the other day.

941-XHP35AH10D0BC4E3
XHP35A-H1-0000-0D0BC40E3
Neutral White, 475lm

I pulled the 20mm Noctigon and used a 32mm Noctigon soldered to a copper disc of the same thickness. So now the HI sits on 1/4” of copper that fills the pill of the light. Took a little trial and error to get the nice hot spot back but in the end I got it. And the base of the reflector sits higher than I would have figured, with this reflector anyway.

This 5000K is a nice white with a hint of the warm side. Crazy that the hot spot is so unified, no sign of it being 4 dies whatsoever.

XHP35 HI C4
Comparing results from this thread and what is available on CREE PTC.
VOB 2.5A - 1370 lumens
Dale 2.39A - 2018 lumens

Dale 0.48A - 648.6 lumens

CREE PTC 50C 0.45A - 633 lumens

It looks Dale's number are kind of matching CREE's at around 0.45A current and 50C, not using the unrealistic 25C numbers which generally are used.



LOL well I have to say that's a little embarrassing. It may well be that I am further out of calibration than I though when using the bare emitter on a slug.

Althought the lux testing I did had nothing to do with this. I still got nearly identical from the de-domed XML2 U4 as I did from the XHP-35


Dale are you using a sphere or one of the light pipes? Did you have to make any adjustment to your divide by for this test?



I'm not really sure yet. The fact remains it does have an amazing beam. Nice hot spot and good throw, I guess I was just expecting a lot more is all.

VOB, the more data from more people the better.

Maybe you guys can accurately measure the die (the multi-de) size of the XHP35, it is exactly XM-L2 size or bigger?

It’s easy to know what twice the lumens is going to look like. Take a second identical light, point it at the same spot and turn it on. To me, it’s never an “OMG” difference, but it is a difference. It is easy to have too high of an expectation and if that is the case, it is easy to be dissappointed. Nevertheless, the XP35 will be a lot brighter, go for it!

I know that second identical light test sounds obvious, but how many have never thought of doing that?



I get about .105" (2.66mm)with my calipers for the total die size of the XHP-35.

i paused my MM18 review and try to test my xhp35 in my lightbox at different amps…

since i have no adjustable power supply i think i try to DD it with different length and thickness cables :wink:

my setup seems to read too high i am afraid ( a 1000 lumen Fenix gets around 1200 in there)
a quick test of the xhp35 showed near 3k Lm @2.5 A
(–20% = 2400 Lm which is still good)