Finally the XHP70.2 emerges!

Djozz tested one but never posted the results as he was getting slightly different results then TomE and some others IIRC.

From what he said it sounds like it pretty much mimics the XP-L2 in the curve though, which makes sense, it is 4 of them put together. So you should be able to roughly look at the XP-L2 and multiply it by 4x.

Yes, as usual I tested one led, and it had its maximum first at 12A and then I reflowed and mounted the same led again more carefully and its maximum was 12.5A. But both Tom and Kawi (in their flashlight builds) reported an output increase when going from 15A to 20A, so that made me doubt about my led and/or my test set-up for these extreme high power leds. Unfortunately these leds are costly so I had no spare one to sacrifice.

If I post my test results they will have to be accompanied by this consideration but usually my graphs are used without the story so until I sorted out where the discrepancy comes from, I rather not post anything at all.

What output would you expect to see from an XHP70.2 in P2 Bin when driven at 5Amps? Thanks!

Rough guess would put around or slightly over 4000 lumens if I had to guess.

Sorry Alex, I’m not at home for the next 8 days (holiday with family in Cornwall, fun in classic cornish weather: lots of rain and wind :party: ) so I have my data not at hand.

Hi all,

Do these emitters display the same nasty color blending issues that XPG3 does? One color (pink usually) in the center with another orange/green color round the edges?

Yes, I have a XHP70.2 P2 1C tint the main beam is has a nice cool white uniform color but the corona has a yellowish tint. :frowning:

Kind of like this, Credit for the image goes to member wkhchin81

Thanks Alex. I can see the pink around the hot spot there too. Man, I cant remember when I got so picky, but it sure makes things a challenge. :smiley:

I just put a xhp70.2 p2 1d from Mountain Electronics in my L6 with a TA driver running narsil from Lexel.

It pulls 17.3 amps after 20 seconds from a couple of liitokala 26650.

I’ll post some beam shots later directly comparing it to the xhp70. So far it seems to have a less noticeable donut hole shape.

Has anybody run “the test” on these yet to see where the point of no return is on current?

Hard to say. With fresh cells in my L6 and pulling 17.3 amps, I’d say 25 to 30 seconds is all I’d be willing to run it at full tilt. It gets hot really quick.

I’m glad I’ve got the ramping firmware so I can dial it back a bit and save full power for special occasions.

If a person wanted to push it harder, at say 20 or 22 amps, to find the limit, how would they do that? Use a power supply to increase the voltage?

My quick, “just out of curiosity test” it seemed to tap out around 21A or so, with substantial cooling…

He is using a TA driver IIRC, so the losses in the driver are very minimal (the same as a few inches of wire). It doesn’t actually adjust the power, it simply turns it on and off very fast so it appears to dim.

I don’t know. All I can only tell you is I’m using a INI-T UT210 clamp meter in place of the tail cap and a big wire just like most others on this forum use to measure.

As far as driver efficiency, I’ll refer to what TA said as it’s his driver design.

Personally, I’ve always heard that fet drivers were quit cool running and very efficient at full power.

These drivers PWM at around 18khz IIRC, not super fast but more then fast enough to not be noticeable to the human eye.

I have never looked up the exact rise and decay times for LED’s but it is really fast. At the rates we PMW it is turning all the way on and off for sure.

I suppose it is possible to make it fast enough to not fully turn it on, I have considered this myself. The issue here is that depending on how fast that needs to be you run into losses switching the FET that fast.

You can actually use a normal FET with a few extra components to create a linear regulator that would basically do what you are thinking of but it would also burn all the excess voltage as heat. This is the fundamental problem with this idea. The excess voltage has to go somewhere and I am not sure that it is possible to reach a balance where it is not all or mostly burned off as heat.

now burning it off as heat is just fine, same thing we do with 7135’s but you are also limited in how much you can burn off before you melt the FET. From testing this appears to be around ~2W of heat dissipation in most cases.

It is possible that you could time things just right to PWM it without a lot of losses and still get reasonably good efficiency but I have a feeling that the LED efficiency would suffer in other ways. It would be interesting to test but I doubt that it would be worth pursuing. At the very least you would need to use FET’s with much higher resistance then we use now and that would not be ideal for max power.

Just a quick test on a Jaxman E2L with triple XP-G2. Thorlabs DET36A/M as sensor.

Rise and fall times are below 1 microsecond. The PWM would have to be in the several megahertz range to hide the PWM.

Good info^! So yeah, kinda like I figured, while technically possible to switch an FET that fast you would end up with as much or higher losses in the FET as you would either going with an linear regulator or normal PWM from an efficiency standpoint all things taken into account.

If a super fast FET’ was used or if we used 2 separate FET’s then it could be possible I suppose. Complicated but possible. Although I still have serious doubt that you would gain much of anything tangible from such a setup.

Here are some beam shots you might find useful.

The new 70.2 does have less of a donut hole pattern. It’s not gone completely, but much better than the xhp70.

The first 2 photos below are a direct comparison of the 70 and 70.2 on my L6 with the same reflector height.

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If I move my reflector away from the emitter just a little, the donut hole reduces more. See below.

Now when you look at these lights without the lower exposure, the donut shapes are much harder to see. The hotspot of the 70.2, which is shimmed out looks really smooth and has sharply defined edges.

Here are the same 3 photos as above, but normal exposure values.

I’ve only had the 70.2 in my light a few days and the batteries are already running down. It seems like I’m getting less than half the run time compared to the xhp70. I’m not using it much at full output, then again, maybe I do have it adjusted a bit brighter than the xhp70. I typically go full power then drop it down a little. That way I’m getting close to full brightness, but with noticably less heat. I’ll report back on the battery usage in a week or two. First impressions are it can can suck batteries dry quick! Lol

Brightness is the same. The camera just made it look brighter for some reason. I didn’t notice this at the time. You can see the background lighting and street lighting are all a little brighter as well. I think the color temp of that photo is also a bit different. I’ll try to adjust it to match the others later.

Has anyone tried the XHP70.2 in 4000K flavor yet.

I currently have the Olight R50 Pro with a XHP70 5000k, but don’t like the blue corona it puts off.

Was hoping XHP70.2 4000K might have a more consistent beam.

Can someone please tell me thier experience with this led before I make the swap.

Or any suggestions on a neutral to warm tint that I should consider for this light.

Thanks