XHP70.2 P2 4000k Output test by Texas_Ace - it's over 9000!! lumens and still going strong!

A big one lol.

Ideal is a relative term. A better CPU heat sink would do the trick nicely, something without heat pipes and good enough for at least 150W, 200W would be better. The problem is by that point you are usually dealing with heat pipes and that makes drilling and tapping the mounting holes almost impossible.

As a compromise the copper core stock intel heat sinks would work fairly well but man, they are hard to drill and tap. I already tried to do that to one I had.

Water cooling?

:smiley:

Indeed, I was very surprised when the output just kept going up and up and up. It didn’t even drop under 100lm/watt until over 7000 lumens!

I don’t really measure the time between measurements, just do them at a leisurely pace. Most likely around 30 seconds for each one.

Over 10,000 lumens for sure. It would be really impressive if not totally impractical lol.

Is it a full CPU cooler setup with a fan? How about putting the heatsink in a pan of ice cold water? Be careful what with the amps and water not mixing though voltage is low enough. Alternately inverted compressed air can?

This is a good idea, but Matt is not very knowledgeable in the subject. No offense to him. A simple copper water block, a high flow pump using 3/8” lines and a bucket of water should easily handle the heat. The question though is whether you just want to keep the emitter cool or to better simulate real world conditions of a flashlight heating up?

Yes, it is a full stock intel 95W CPU cooler. I also had a 135W stock intel cooler with the copper core but it ate all my small drill bits.

I like to simulate real world conditions to some extent, which is why I was never that worried about getting the biggest heatsink around. Even this test is not something I am particularly bothered about. The cold start tests show what it can do on a cold start but the hot tests are more what can be expected in the real world.

Yeah, using a giant CPU heatsink or AIO cooler should be able to get you those 10k lumens continuously :wink:
Definitely not a “normal” flashlight use case though.

Very interestingly, I sliced the dome on the xhp70.2 in Giggles and the Kcd jumped by over 50%!

I would not have guessed it would gain that much.

It went from ~450kcd with the dome to over 700Kcd with the (badly) sliced dome.

All of this with only ~90w of power, it could do even more if you pushed it.

https://www.ebay.com/itm/5PCS-CPU-GPU-Thermal-Silicone-Grease-Compound-Glue-Heatsink-Plaster-STARS-922-5g/152180587367

I'd use some small dabs of thermal glue among the thermal paste between the heatsink and the led baseplate. This way you can use a massive high performance CPU cooler without worries. To disassemble it help yourself with some alcohol and/or white spirit, can't remember which one did the trick for me right now.

Cheers :-)

Maybe now it’ll be more believable to folks that I had an L6 running 9200 lumens. Believe it or not, doesn’t change what it’s doing. :wink:

This is actually where the test LED will end up once I get my soldering iron replaced.

Circuit Specialists have had some sales going on.

I was impressed by the luminous output of the xhp70.2 in my chimera but not by the ugly halo. That said, in real-life outdoor use the halo isn’t as obvious as on a wall and four months use with hundreds of hours at low and mid levels with a ta srk driver from lexel powered by 8x (2s4p ncr18650b) impressed me enough I haven’t replaced it. The chimera handles heat well enough that with the 70°c step down it still hasn’t stepped down from turbo at 20 minutes.

50% is quite large! Usually it’s 25% to 30%, isn’t it?

Do you think the overall result is positive or negative?

You loose lumens as well as have a smaller area the hotspot covers, but gain distance.

When I sliced my older xhp70 I found the end result was negative as I prefered the bigger hotspot and brighter output. Maybe it’s a personal preference thing?

I noticed the sliced hotspot size was pretty much the same as a xhp50.2 with the dome on.

I would speculate that a sliced dome xhp50.2 would give the same hot spot size as a xhp35 HD (with dome).

So you get 4 steps of hot spot size:

Xhp35 hi

Xhp35 HD
Xhp50.2 sliced

Xhp50.2
Xhp70.2 sliced

Xhp70.2

You start with the smallest hot spot, the lowest lumens and the lowest amp draw. Then as you go down the list the hotspot size goes up.

I wonder how the 50.2 and sliced 70.2 compare as far as amp draw for the lumens they put out?

I’ll have to sit down and crunch the numbers one of these days.

Yeah, after refcusing this setup is growing on me. Never been a fan of dedomed LED’s before but this one is tolerable.

Particularly outside you hardly notice the tint shift unless you are looking for it.

It is tough to say at this point which I prefer. Dome on or off.

The dome on tint was a bit better and it most likely had more lumens, although it does not seem to have lost as many lumens as the old xhp70 did without a dome.

The biggest gain is the (almost) elimination of the dark spot.

I was never a fan of sliced domes on the old XHP70 but this one is not bad.

All said and done, if the dark spot could be eliminated with the dome on, I personally would most likely just leave it like that. 1300m of throw is more then enough and the larger hotspot and better tine are good.

With the dark spot as it is right now, I would say it is a toss up. Once I get the V1 prototype back I will most likely try a dome on vs dome off side by side comparison.

Now if Lumintop could be talked into reworking the reflector to eliminate the dark spot and making the xhp70 mcpcb, then that would really open up options.

The xhp50.2 would be an interesting match, I have one here but no mcpcb for it that would fit.

Although given the results with the xhp70.2, personally I think I would go for the higher output it offers and live with a bit less throw.

I don’t think that is physically possible without reducing the throw.

A reflector shaped for maximum throw is always going to be weaker in the middle of the hotspot.

You could get a smoother hotspot 4 ways, but they all reduce throw:

Adding texture to the reflector

Adding a light diffuser film to the lens

Offseting the emitter to the side a little.

Unfocus the emitter up and down, depth wise with the reflector.

When I was chasing throw with my L6 I tried all kinds of experiments, But ultimately I decided to make the hotspot look nice to me regardless of what the throw numbers said.

Yep, that is what I was getting at. The reduction in throw is generally worth the better beam I have found. For example going to an SMO reflector in the L6 makes the beam not nearly as pretty to look at but only gains a little throw. So I stuck with the OP reflector.

In general I prefer the OP reflectors myself but not really what we are going for here.

The beam is pretty good, it only needs a little push to make it really good with the dome on.