Testing a Cree XHP50.2 J4 3A led

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texas shooter
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This test was done on the J4 looking pretty spectacular. Cree list a K4 that does 350 more lumen at 3 amps than the J4. So 5000 lumens is very doable, just not as pretty as this J4 A3 5000K LED. Now just sit back and wait for the Cree XHP70.2 cause the Heart of Texas is going to have scorch marks all over the place.

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Texas_Ace wrote:
I have seen people use a 36k for a 3s setup and 48k for 4s IIRC. Although they still needed fine tuning in the firmware IIRC. Still it shows you need to increase R1.

Thanks TA, exactly the ballpark information that I wished for. I will try swapping R1 for 33K and see what happens. Smile
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You would need a fixed voltage drop of 3.0 Volts over the 220 Ohm resistor, so that when the Voltage goes down to 6 Volts the driver will get 3.0 Volts and low voltage warning will happen.
So i think you can replace the 220 Ohm resistor with a 3.0 Volts zener (in ‘anti-series’) and forget about the parallel zener (from the zener mod).
But, that means the MCU gets maximum 5.3 Volts minus the 0.6 Vf of the protection diode = 4.7 Volts maximum.
I don’t know how much Voltage the MCU can take though, and i haven’t tried this idea either…

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Jerommel wrote:
You would need a fixed voltage drop of 3.0 Volts over the 220 Ohm resistor, so that when the Voltage goes down to 6 Volts the driver will get 3.0 Volts and low voltage warning will happen. So i think you can replace the 220 Ohm resistor with a 3.0 Volts zener (in ‘anti-series’) and forget about the parallel zener (from the zener mod). But, that means the MCU gets maximum 5.3 Volts minus the 0.6 Vf of the protection diode = 4.7 Volts maximum. I don’t know how much Voltage the MCU can take though, and i haven’t tried this idea either…

When I tried using the zener without the resistor the zener fried in a matter of seconds.

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Jerommel
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Texas_Ace wrote:
Jerommel wrote:
You would need a fixed voltage drop of 3.0 Volts over the 220 Ohm resistor, so that when the Voltage goes down to 6 Volts the driver will get 3.0 Volts and low voltage warning will happen. So i think you can replace the 220 Ohm resistor with a 3.0 Volts zener (in ‘anti-series’) and forget about the parallel zener (from the zener mod). But, that means the MCU gets maximum 5.3 Volts minus the 0.6 Vf of the protection diode = 4.7 Volts maximum. I don’t know how much Voltage the MCU can take though, and i haven’t tried this idea either…

When I tried using the zener without the resistor the zener fried in a matter of seconds.

Yes, but that’s when you use the zener in prallel, and that’s to be expected.
What i’m proposing is putting a 3.0 Volts zener in series (but the ‘wrong way around’) in stead of the 220 Ohm resistor so you use its reverse voltage drop.
It will then just eat 3.0 Volts of 6.0 to 8.4 Volts, so that when battery drops below 6 Volts, the MCU will think it’s 3.0 Volts and starts blinking in low mode.

[edit] i suppose “reverse Vf” is called Vr Smile

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Yeah, and you still need a 10Uf on C1. The Zener likes having it’s own 10Uf for stability, but the designed C1 I always populate too.

I’ve used a 39K at R1 but got away from it by changing the firmware.

Dale

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This is getting a bit off topic i guess..
But my idea is to avoid SMD soldering as much as possible, so i’m thinking about using a fixed 3 volts voltage drop in stead of a 220 Ohm resistor and the parallel Zener.
You can obtain 3 Volts drop with 5x Si diode in series, but that’s a but bulky..
So i though about using a 3.0 Volts Zener in series, that is, if they even exist… Facepalm

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…more on topic, i superimposed Djozz’s XHP50.2 test graph on Djozz’s XHP70 test graph:
.

The XHP50.2 is plotted in green.
More on the XPH70 test: http://budgetlightforum.com/comment/723307#comment-723307

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Nice work Jerommel.

My current and or voltage measurements are only relevent to anything that I measure.

Budget light hobby proudly sponsored by my Mastercard and unknowingly paid for by a hard working wife. 

djozz said "it came with chinese lettering that is chinese to me".

old4570 said "I'm not an expert , so don't suffer from any such technical restrictions".

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Basically what I figured, the xhp50.2 should give the xhp70 a run for it’s money without a donut hole. Not a bad LED option for sure if we can find some drivers capable of driving it properly.

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I think I will buy one to try in my L6 which is bumped to 7.4A. And I have a SMO reflector for it.

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I have a couple stock SD75’s with OP and SMO reflectors, FETDD drivers, LD2-3 at 12 amps that I would like to try this in, but is 5000k the highest tint/kelvin/temp out? If possible a link to it would be greatly appreciated.

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Texas_Ace wrote:
Or another rather interesting option would be to have a pad for an FET on the mcpcb for heat sinking and then use an opamp LD3 style driver to control it. By having it on the MCPCB the heat sinking should be good enough to allow it to handle it.

Still lots of extra heat and inefficient but at least it is variable and as such the efficiency will improve as the voltage drops.

Alternatively, could there be a special FET MCPCB that would mount to the driver side of the LED shelf? Starting from the front of the light, there’d be a sandwich like this:

LED
LED MCPCB
LED Shelf / Pill
FET MCPCB
FET
Airspace
Driver

with a couple of small bolts keeping the FET MCPCB in place, and suitable amounts of thermal compound.

This assumes enough space in the driver cavity, of course, but it might help to avoid space problems on the LED side, given that reflectors / optics tend to sit quite close to the surface of the LED MCPCB, and the LED itself sits so inconveniently in the middle Smile

It also allows the use of any stock LED MCPCB and keeps the FET gate wire wholly inside the driver cavity, if that makes a difference.

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Jerommel has given the graph an incorrect fuzzy title (although he did refer to the origin of the graph where the correct information can be found). The title says that the the XHP70 test was ‘in less than ideal circumstances’ while in fact in the graph two XHP70 tests are to be seen, of which the purple one is wrong and must be ignored (the led was reflowed on a bad performing makeshift board), the red graph is correct, on a quality copper DTP board, under as perfect circumstances as I can create them.

I always make a point of giving my graphs headers that describe the contents as complete as possible so that they can be copy-pasted without loosing their context, but Jerommel (unintendedly), by writing a new header, has removed that context here.

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I have an Acebeam K60, if I install this led and according to the graph I would lose around 600 lumens but gain more throw? Doesn’t sound like a bad trade. Love

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djozz wrote:

Jerommel has given the graph an incorrect fuzzy title
It’s a disclaimer actually, because it’s not made by you this way, not based on your measurements but by image manipulation done by me.
Quote:
(although he did refer to the origin of the graph where the correct information can be found).
of course.
Quote:
The title says that the the XHP70 test was ‘in less than ideal circumstances’ while in fact in the graph two XHP70 tests are to be seen, of which the purple one is wrong and must be ignored (the led was reflowed on a bad performing makeshift board), the red graph is correct, on a quality copper DTP board, under as perfect circumstances as I can create them.

You wrote the red line represents an abused LED (resulting in higher Vf and lower output, but on a proper MCPCB) so i wouldn’t call that ideal circumstances either.

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I love the charting, the information it imparts, the graph showing all the pertinent aspects give a great idea of what to expect…

However, I have an XHP-70 in a Convoy L6 making 7245 lumens at 11.97A, far above the plot and respectably higher than the XHP-50.2 shows. Not sure then how to interpret the graph.

While I do have 4 of these 5000K 50.2’s on the way, the main plan is to build 3 of them into a triple. I don’t know quite yet what I’ll do with the 4th, perhaps put it in another L6 and build the same ramping driver as the other for a direct comparison?

Dale

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Phlogiston wrote:
Texas_Ace wrote:
Or another rather interesting option would be to have a pad for an FET on the mcpcb for heat sinking and then use an opamp LD3 style driver to control it. By having it on the MCPCB the heat sinking should be good enough to allow it to handle it.

Still lots of extra heat and inefficient but at least it is variable and as such the efficiency will improve as the voltage drops.

Alternatively, could there be a special FET MCPCB that would mount to the driver side of the LED shelf? Starting from the front of the light, there’d be a sandwich like this:

LED
LED MCPCB
LED Shelf / Pill
FET MCPCB
FET
Airspace
Driver

with a couple of small bolts keeping the FET MCPCB in place, and suitable amounts of thermal compound.

This assumes enough space in the driver cavity, of course, but it might help to avoid space problems on the LED side, given that reflectors / optics tend to sit quite close to the surface of the LED MCPCB, and the LED itself sits so inconveniently in the middle Smile

It also allows the use of any stock LED MCPCB and keeps the FET gate wire wholly inside the driver cavity, if that makes a difference.

The problem with this is that it would not work with all hosts, only those that have a thick enough shelf to allow a screw to be used to mount the bottom side mcpcb among other issues. If you were desinging a light from scratch there are lots of ways to power the xhp50.2 but in a retrofit setup we are much more limited and need a more universal option.

A good preforming buck driver is the best idea but the best we have at this point is the mtnmax with ~5A.

The Second Amendment is in place in case the politicians ignore the others.

Government is the great fiction, through which everybody endeavors to live at the expense of everybody else. -- Frederic Bastiat , French economist(1801-1850)

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My LED Test series - XP-L2 V5  - Nichia 219C 90+ CRILatticebright "XM-L"XHP35 & PWM efficiency - XHP50 - XP-L V5 - XM-L2 U2 - XP-G3 S5  - XP-L HI V2 - Oslon Square & direct comparison to Djozz tests - Nichia 319A - Nichia 219B 9080 CRI - Nichia 219C D320 - Nichia 229AT

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DB Custom wrote:
I love the charting, the information it imparts, the graph showing all the pertinent aspects give a great idea of what to expect…

However, I have an XHP-70 in a Convoy L6 making 7245 lumens at 11.97A, far above the plot and respectably higher than the XHP-50.2 shows. Not sure then how to interpret the graph.

While I do have 4 of these 5000K 50.2’s on the way, the main plan is to build 3 of them into a triple. I don’t know quite yet what I’ll do with the 4th, perhaps put it in another L6 and build the same ramping driver as the other for a direct comparison?

Your xhp70 is a P2 bin where the one djozz tested was an N2 bin, that explains the bulk of the difference in readings.

Also his readings are “hot readings” and yours are turn on / 30 second readings. I notice big jumps in output from a cold start vs a steady state test, easily explaining a large part of the remaining difference.

The final ~5-10% would simply be sphere calibration differences.

The Second Amendment is in place in case the politicians ignore the others.

Government is the great fiction, through which everybody endeavors to live at the expense of everybody else. -- Frederic Bastiat , French economist(1801-1850)

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My LED Test series - XP-L2 V5  - Nichia 219C 90+ CRILatticebright "XM-L"XHP35 & PWM efficiency - XHP50 - XP-L V5 - XM-L2 U2 - XP-G3 S5  - XP-L HI V2 - Oslon Square & direct comparison to Djozz tests - Nichia 319A - Nichia 219B 9080 CRI - Nichia 219C D320 - Nichia 229AT

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Does raise the question though, if one should do a graph based on ‘hot readings’.

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http://budgetlightforum.com/comment/723307#comment-723307

..is the post with the corrected XHP70 led.
@Jerommel: it used the same led as the first, imperfect, test, and it does state that the led had suffered somewhat, but the few % that that mattered can hardly be called less than ideal.

@Texas Ace: thanks for the explanation, but if you add that all up you still do not get to Dale’s numbers comfortably: in the above linked post you can find a cold start test as well, at 12A/30seconds that led did 6024 djozz-lumen, the difference between P2 bin and N2 bin is a factor 1.15, so that makes 6933. In my experience OTF of a common ok quality flashlight (without super fancy reflector and lens) you loose about 18%, so that makes 5685. That makes Dale’s reading 27% higher than mine.

But that does not really startle me anymore btw, the few attempts (texas pyro, sma, Zweibrüder integrating sphere and Texas Ace) that I made to compare different people’s calibrations, in most cases showed way larger differences than I expected and wished for. I was within 1% of sma, 9% over the LedLenser sphere, can’t remember tp but it was between 20 and 30% different, and between TA and me it was 5% or 20% depending on which light source Sick )

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djozz wrote:
http://budgetlightforum.com/comment/723307#comment-723307

..is the post with the corrected XHP70 led.

Yes, that’s the post i linked and took the graph from.
Quote:

@Jerommel: it used the same led as the first, imperfect, test, and it does state that the led had suffered somewhat, but the few % that that mattered can hardly be called less than ideal.
Perhaps you use a fuzzy incorrect definition of “ideal”. Wink
In the red graph the Vf shouldn’t be higher than in the purple graph (at least, not below 4.5 Amperes or so, should it?), and the output in the red graph should never be lower than in the purple graph.
This way the result is that the green XHP50.2 graph looks better (compared to the red graph) than it should.
(doesn’t it?)

Either way, i did it just to illustrate things, but with keeping the circumstances of the XHP70 test in mind.
Maybe i should have written: the state the XHP70 was in, was not ideal in the red graph.

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@djozz - Thanks for the thread!  Can the XHP50.2 be a direct replacement for XM-L emitters? (I'm thinking yes due to the exact 5x5mm base but not sure about the connections)

Also, any tips on perfectly centering the emitter during an upgrade? I saw your home made reflow thread and am potentially interested in making one. After so many years, decided to finally try a little modding... Silly

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Ok, so at any rate the new 50.2 seriously outperforms it’s older brother the 50, might as well go apples to apples instead of comparing the 50’s to the 70’s.

Yes, I did go to the highest available bin on my L6’s XHP-70, I also put it on a 26mm MaxToch copper mcpcb. No matter how you look at it, it’s a bright mamajama and get’s the job done for sure! Smile

Dale

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What determines the max output voltage of a buck driver? i am ondering if it is possible to use a 2s buck driver that is designed for 3v output with a 6v output. I get changing the current sense resistor alters the current output but what limits or sets the voltage.

I would have thought that the buck driver would allow the voltage or rise as long as the current is under the limit but this is clearly not the case. I hooked up an mtg2 to a buck driver like those that can be found in any of the commercially available tube lights, I think this one was an olight s30 driver, and it did not light up. If I remember right it was just a faint glow visible over the emitter. So what would make a driver like this be able to output a higher voltage? Is there voltage limiting circuitry and therefore not possible?

I also have a couple nitecore ec4s hear and I heard mention that the buck driver in this light will light up a 6v led. Pretty sure I heard that somewhere?

So,what’s the skinny Question

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Every buck driver is different in how it works and the limits. sometimes the IC will fry with too much voltage, others the caps and others it simply doesn’t know what to do with higher voltage.

Some will work higher and others will not. almost all will have more ripple if used outside the design specs.

The real issue is not voltage but current. Getting a high voltage buck is simple, getting a buck that can handle more then 3-4A of current in a reasonable form factor is the hard part.

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Government is the great fiction, through which everybody endeavors to live at the expense of everybody else. -- Frederic Bastiat , French economist(1801-1850)

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My LED Test series - XP-L2 V5  - Nichia 219C 90+ CRILatticebright "XM-L"XHP35 & PWM efficiency - XHP50 - XP-L V5 - XM-L2 U2 - XP-G3 S5  - XP-L HI V2 - Oslon Square & direct comparison to Djozz tests - Nichia 319A - Nichia 219B 9080 CRI - Nichia 219C D320 - Nichia 229AT

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Jippie!

I’m an unlucky noob when it comes to finding or making high current drivers for 6V leds so I put the test led from the OP in a 2×18650 thrower with a smooth 45mm diameter reflector, with no driver at all (used the cleared stock driver board just as a contact plate), un-bypassed springs on both sides of the batteries (tail spring is chosen very long to tame the current a bit).

On VTC4 batteries at ~4.05V I got 12A (too much), with 30Q’s at 4.05V I got 10A (still a bit much). With the 30Q’s I measure 3900 lumen at start, 3050 lumen at 30 seconds, and because the light is pretty lightweight built, at that point the head temperature near the pill was about 60 degrees.

Like other new Cree leds the (very nice!) hotspot is slightly on the blueish side (but by far not as bad as the XP-G3) with a slightly yellowish corona. But who cares with this output, it is great to see so much big throw coming out of a 3000+ lumen flashlight, With some luck it is more than 200kcd Big Smile

edit next morning: did the measurement and it is just 70kcd. Facepalm

It is late now but I will make some pictures tomorrow plus a beamshot or two. And measure throw.

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I am actually surprised that the current is that low with the 30Q, although be careful your springs don’t melt. I find that long 24AWG wires are a better option for the resistance and then small 26awg bypasses on the springs.

The Second Amendment is in place in case the politicians ignore the others.

Government is the great fiction, through which everybody endeavors to live at the expense of everybody else. -- Frederic Bastiat , French economist(1801-1850)

Texas Avenger Driver Series

My LED Test series - XP-L2 V5  - Nichia 219C 90+ CRILatticebright "XM-L"XHP35 & PWM efficiency - XHP50 - XP-L V5 - XM-L2 U2 - XP-G3 S5  - XP-L HI V2 - Oslon Square & direct comparison to Djozz tests - Nichia 319A - Nichia 219B 9080 CRI - Nichia 219C D320 - Nichia 229AT

How I made a True integrating PVC sphere with no math involved

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djozz wrote:
Jippie!

I’m an unlucky noob when it comes to finding or making high current drivers for 6V leds so I put the test led from the OP in a 2×18650 thrower with a smooth 45mm diameter reflector, with no driver at all (used the cleared stock driver board just as a contact plate), un-bypassed springs on both sides of the batteries (tail spring is chosen very long to tame the current a bit).

On VTC4 batteries at ~4.05V I got 12A (too much), with 30Q’s at 4.05V I got 10A (still a bit much). With the 30Q’s I measure 3900 lumen at start, 3050 lumen at 30 seconds, and because the light is pretty lightweight built, at that point the head temperature near the pill was about 60 degrees.

Like other new Cree leds the (very nice!) hotspot is slightly on the blueish side (but by far not as bad as the XP-G3) with a slightly yellowish corona. But who cares with this output, it is great to see so much big throw coming out of a 3000+ lumen flashlight, With some luck it is more than 200kcd Big Smile

It is late now but I will make some pictures tomorrow plus a beamshot or two. And measure throw.


Cool beans Jozz! Ordered some 50.2 J4-1A’s to compare against a Convoy L2 with a old XHP50 J4 1A that’s shaved and pulling 8.57 amps. at turn on. I plan on putting it in my spare L2 and add resistance to around the same current maybe? I can’t believe what I just said! Facepalm Can only measure throw, but at least it will be apples to apples, and see what it looks like out of a smooth reflector! Thumbs Up

KB1428 “Live Life WOT”

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