Testing a Cree XHP50.2 J4 3A led

Tested. One channel smoked, sorry…. :stuck_out_tongue:

- Constant current 3 channel buck driver rated for 12-15V I guess…Bought from Ebay somewhere in 2013

- Designed as 2x5watt low beam and 15watt high beam (in high beam all three COBs turned on) per module

- 3 x 6V unknown super low CRI 6500+ K COB LED. Wired for 2 Lo and 1 Hi beam.

  • Each channel outputs 0,87A-0,88A. You can combine all three in parallel to get 2,64A total.

Tried with 3 x XPG 4500K bought from Sedstar (super nice and dirt cheap). Link: Sedstar 4500K XPG
These are good cheap LED with known spec, perfect for testing any project. You can use your fancy LED later

Worked fine with 3 XPG: roughly 9V, 7,9watt/channel. Could be wired for a total 3 x 7,9watt = 23-24watt total.

With 2 x 144AM (6V); roughly 10,56watt per channel the IC smoked less than 10 minutes. So you better limit the output to ~8 watt/channel. With new XPG2/3 or 219C you will get lower output power since the vf of these newer LED are lower but possibly still brighter than the good old XPG. If you can find the same IC it should easy to fix, I think it’s common IC found online.


If you want to use this driver you better cool the inductor, they got very warm (not too hot) with 3 x XPG. Hence the fan.
The fan got very noisy after ~1 year street use. The salty balinese dust sucked rubbed the exposed plain bearing.

@JasonWW: We never wanted to use those badly designed LED engine. I offered Stormrider the driver, not suggesting him to use it as is. It’s an awful kind of LED lamp indeed. I bought it during the dark ages when anything brighter than halogen bulb attracted me. And no, I really hate cool white headlight, no matter what CRI they are.
As for the image hosting, try Flickr. Rather complicated but allows you to store very high quality images complete with copyrights protection and rich features.

Flickr seems popular. I’ll just go around the forum looking for pictures that still show up and see what host they use. :wink:

For me, anything less than cool white looks dingy. Like old style incandescent bulbs. I can’t stand it.

Cool white for me is anything over 5000K. I prefer to work under 5700K high CRI. Driving is another thing, on whitish cement road or behind white painted car, anything above 5000K irritate my eyes. Try tailing a white ambulance with CW HID on a empty twisty country side road (no street lights).
But yes, lower than 4000K everything looks not so good (for driving).

- Clemence

Yeah, like I mentioned in post 229, I have an old 86 Honda vfr700. It’s got LED headlights (and just last week, LED tail lights).

Reminds me of the old pocket rocket: Honda RVF400
Revving up to 15000RPM each upshifting, with 4-1 pipe sounds like a crazy mosquitoe from afar. The whiney timing gear sound also very distinctive. Those were the days…

Yeah, that’s the smaller, and slightly newer version of my bike. Great V4 engines.

No, I did not.

I mainly don’t want to sacrifice the factory beam pattern just to get a slightly warmer tint. That’s what happens when you move to an xhp50, xhp70 or XML size emitter. Good beam pattern with a sharp cutoff line is my highest priority. The second highest priority is being noticeably brighter than the stock incandescent bulb. Then a lowly third is a good enough color temperature.

The first two can be accomplished with a little hunting around and maybe small modifications. Then you’re stuck with whatever color they give you. Usually that’s cool white.

My first set of car LED headlights were cool white with a tiny bit of blue, but my current set of headlights are actually a more pure white without any traces of blue. Color reproduction is quite nice.

Oh well, just trying to help.

That looks easy enough, heatgun or hotplate will desolder the LED without ruining the rest of the components.

  • If it’s MCPCB then hotplate is the easiest way, at 240C bed temp all 60/40, 63/37 lead and SAC305 leadfree solder will melt completely without excessive yellowing of the solder mask. Don’t let the board stayed too long on it, you’ll yellow the masking ink.

- If it’s FR4 board preheat slowly no more than 120C for 5 minutes on hot plate followed with heatgun ontop. Make sure you put a thermocouple fixed on the board so you can monitor the temp (240-260C) is max reflow temp according to many component’s specs. Place your heatgun gradually closer as the blower could blew the components off the board. When you start to smell burnt epoxy shut the heatgun off or move it farther away from the board.
The better way for FR4 boards is Infra Red top heater oven such as found in your toaster. The resin-fiberglass matrix has very low thermal conductivity making hotplate technique harder and requires longer preheat time.

- Clemence

Haikelight wrote somewhere they fixed the green tint shift, any idea how?

Am I correct when I say:
4 x XHP50.2 driven at 6A each (so in a Q8 like configuration 24A from the driver) produce 16K lumens
?
I have an idea for the future Q16 and 16K lumens would be so awesome but I would not want a green tint shift.

coarse OP reflector?

ah, could mbe, i have not seen a review on the updated version

Remember that the xhp runs at 6v so 24A at 6V would be the same as 48A at 3V. AKA, it would get VERY VERY hot. You will really need a buck driver to drive these as well due to the super low Vf they have. 4 of them together could pull as much as 72A of current on a low resistance FET driver based on other peoples results.

That is a whopping 425W of power! Or over 5 times the amount of heat that the Q8 produces right now. Also I would not trust the LED’s to survive that long term.

That said, the xhp50.2 should be capable of about 5k lumens each maxed out although 3.5-4k each is a more reasonable goal IMHO. It also keeps the heat a bit more reasonable.

As I have said before, a quad xhp50.2 Q8 should be able to make around 15k lumens without much trouble and more if you push it. Or drop it down to ~10k lumens and it should have about the same amount of heat and battery life as the XP-L’s at ~6k lumens. If you just really want to hit 16k lumens for the numbers to match up, then yes, that should be possible.

Now for the green tint, this is not really an issue I have noticed unless you get a funky tint LED from above the black body line (like a 3C vs the good 3D for example).

The newer LED’s do have some yellow tint shift but that is largely reflector dependent from what I have seen. Larger and deeper reflectors with OP don’t have an issue.

Optics like the cute-3 work great and removing all the tint shift but that would not really work for the Q8.

The only practical way of doing this is to use a buck driver with the cells in 4s and the LED’s in 2s2p. By upping the voltage to 12V you drop the current needs down to around 12A. This is doable with repetitively cheap buck drivers like a beefed up version of the GT driver.

Wired in 6V they would need twice the current and the driver would cost a fair amount more as well.

Basically a Q16 is possible and would work for sure but would also cost more for sure.

The component/connector is pretty decent, light brand/type ?
Can you wrote marking/code on top of U1 please? Interesting package for IC

Resistor near LED possibly a Thermistor (marking RT1) act as thermal feedback for the driver itself

cool. thanks TA!

In this picture you see XPL HD LEDs with 3535 footprint, XML2 have 5050 footprint and wont fit

You can replace em with Nichia 219 High CRI LEDs

Hahaha nice one Lexel, I never played with XML2 too much, I didn’t put too much attention to the LED when I saw the picture.

@Stormrider: he ask you to write him the code/type of the big IC in the middle between the LED

No, I did different exposures to show the beam profile clearer. The XPL is slightly brighter than 319A.

Check Texas_Ace’s signature for the test results. He did a very good test comparing XPL/XPL2 and 319A a while back.

Stormrider, I suggest you to create a new thread in Headlight section. We’ll continue there, for the sake of better indexing. So people will get what they “googled” for in BLF.

We’re already too far off the original topic here. This is a very interesting topic indeed and I think we better share it in the matching section so people can easily find it when they need related information.

See you there… :slight_smile:

- Clemence

I think a new topic would be better. :slight_smile: