Finally the XHP70.2 emerges!

I does not know any mcpcb where the terminal pad is connected to LED+ or LED-.
Only some LEDs like Osram Oslon black flat have a connection between terminal Pad and LED-.

With DTP (direct termial path) the terminal pad can be connected to the flashlight body, which mostly is connected to battery-.
A connection of battery+ to the flashlight-body is very rare. I have made such a connection in a Skyray King with Nichia 144 LEDs, which do not have a terminal pad.

The diode contacts are not isolated from thermal pad, just look at image from kd. I want to use boost driver that require thermal pad to be isolated from driver out.

OK, now I know what your problem is.
… as it is written in the datasheet of XHP70: “Recommended PCB Solder Pad 12 V Configuration (thermal pad is connected to anode and cathode and is not electrically isolated)”

Than you need to do it yourselfs.

On the 6V Board, you can cut the traces in the middle of the + and - pads to connect the new pads among each other. That means, you will not need capton. You can use the “CREE” and “XHP70” scripting on the board to connect the new pads with a cable.

Interesting.
Still waiting for someone to test the XHP70, 20A without burning up and still making good output sounds impressive based on the rough tests a few posts ago.
If it can do 20+ A with less than 8.4v then it will probably do more than 0.5A with 12.6v in the 12v configuration.
Only tests will tell for sure :slight_smile:

I received a XHP70.2 from KD (P2 3B) yesterday and did a test with my usual method. I could not repeat the results of Tom and Kawi, the led maxed out at 12A (I measured 6600lm), above that the output slowly went down. I stopped the test at 15A. After cooling down I tried going directly to 15A and got 8000lm at start and 7000lm at 30 seconds. Considering that Tom got comparable numbers but out the front of a flashlight, so maybe 15% less compared to bare led lumens (which would be 9200lm and 8000lm), I’m on the low side of them.

I checked my reflow by unsoldering the led, and the led made good contact over the entire solder pads.

A very possible explanation for our differences could be my way of mounting. I think the (active, with a fan) cooling of my rig is good enough or at least as well as the flashlight builds of Tom and Kawiboy, but the (20mm) ledboard was not soldered on the heatsink, but screwed down tight with thin ArticSilver5 in between. With the close to 100W of heat to dissipate, this may be a limitation. When I have time I will solder the 20mm star onto a larger 3mm thick copper disc, and clamp that to my test-mount, so that the contact surface is way larger (more than 3 times). Then I will do the test again, and make a post about it.

Oh boy, interesting... I posted this in a L6 mod thread a few mins ago:

Last night I charged up the solder blob topped LK 5000's to 4.20V and re-tested. Actually I use only one that's solder blob'ed since there's a driver spring, bypassed of course.

Amps at the tail: 17.3A, lumens: 9,210 @start, 8,160 @30 secs, and 193 kcd @5m (879 meters)

Parasitic drain is 62 uA (no indicator LED on this L6), so pretty happy with that low reading. No need to turn off the power switch.

Thanks to steel_1024 for the XHP70.2 P2 3B!

It's an impressive thrower, but way too much heat to handle, but that's what thermal or timed step downs are for.

I'm not using/doing anything crazy - basic DTP copper 20 mm MCPCB, MX4 thermal grease, screwed down to standard L6 shelf. I really do like the way the traces are on the MCPCB I'm using though, shown here: https://budgetlightforum.com/t/-/44818/89

Even Dale with a XHP70 P2 1C got 7,000 lumens, think at 12A. True our lumens are generally higher than yours though. Think Dale's might be slightly higher than mine, but we're pretty close.

Those results sound about right and are honestly what I was expecting. I have noticed that from a cold start you can generally get away with a lot more current then with a steady state test like we do. Although those results will quickly peter out as things heat up.

So running it at 20A will work but only really net you better output for the first 30-60 seconds or so.

Hhmm. You sure you got a good reflow? The main thing I don't like about the MCPCB is no escape for extra solder, so I was as careful as I could be to not use too much. The reflow seemed like it came out perfect - one of the best I've done, but I've had a few stinkers in my time .

Tom, since your ledboard was not soldered down either, I will do a re-test in my usual way without soldering the board. After the test I pulled the led off the board and back on, that may have improved the reflow a bit. Also, I will use larger stiffer rings under the screws so that the pressure is more to the center of the board.

Maybe tonight but it can be later as well.

Do you guys quickly pop down the emitter during reflow to eject the excess solder?
Look here at the 7:40 to 8:20 mark.

Actually the whole video is really good.

No time to check the vid but sometimes yes, usually no. Not long ago I had a reflow with too much solder - pressed down and it just popped right back up - just couldn't get it to sit right. I need to check the vid though to see. Suppose if you hold it down and let it cool, should get it down. Gotta be so careful though to not move the LED off of proper pad alignment - not sure I could do that.

If you “pop” the LED down hard enough it will spit the excess solder out. I generally do this on all the LED’s I reflow. It was a very good idea as it is very hard to get enough but not too much solder otherwise.

Thank you all for your tests and posts! The XHP70.2 sounds finally like the LED which I have been waiting for so many years :smiley:

Yep, hold it down and blow on it…that’s my weird method…doesn’t take but a few seconds to cool and stay down.

Yeah, no, I don’t build flashlights for “regular use” or walking dogs or stuff like that.
If I need a flashlight for work or EDC I buy a factory assembled light with enough lumens and throw.

What I build is stuff that pushes limits, usually not very practical for carrying around often.
If I can upgrade my XHP70 at 12A to an XHP70.2 at 15-20A I certainly will :slight_smile:
I hate DD though so I would need to find a CC driver that can do that much current.

Imho most factory assembled light sucks… And that counts even for some “premium” China brand manufacturers.

So I re-did the test with extra emphasis on getting the mounting right. I did see some improvement in the numbers: slightly higher voltages and the maximum is now 6860 lm at 12.5A, but from there it goes slowly but steady down again.
After a complete cooldown I will try a 15A and a 20A burst but I’m afraid that I will not get to the previously reported results.

I’m not sure what to do with this, I may have a particularly low performing led, or perhaps one way or another my test method is not suitable for such high powers. I’m reluctant to post emitter test results that several others have found to be not correct.

djozz, it is troubling when different measurements don’t agree. Back when the XHP70 came out and you measured it there were also discrepancies between your measurements and measurements done in a flashlight at turn-on. Then you took some measurements at turn-on and that cleared up the discrepancy, right?

I’m interested to see your results.

More goodies:

Little pricey but if you wanna play...

Hoping for 3 of these to go in my MT03.

Just to satisfy my curiosity I put the 70.2 P2-1A JAX X6 (18-20amps) using a L6 OP reflector against a L6 70 P2-1C (12-13amps) OP reflector and on the meter and visually (side by side) the 70.2 P2-1A “Out Performed” (stunningly) the old XHP70 P2-1C, as apples to apples as I can get! :wink:

Carry on…… :+1: