Nitecore EX10 UV

[MorpheusT1]

I am not the new owner of this light.
But i wish...:nana:

Those Sense resistors are waay to small for me to fiddle with,ive broken my share with my 4 thumbs.

So these buggers are only seeing like 300mA?
Pretty bright regardless.

How do you guys go about to swap the emitter?
Reflow on a new emitter on the existing star or do you use a diffrent PCB?






Benny

 

[CM]

I am not the new owner of this light.
But i wish...:nana:

Those Sense resistors are waay to small for me to fiddle with,ive broken my share with my 4 thumbs.

So these buggers are only seeing like 300mA?
Pretty bright regardless.

How do you guys go about to swap the emitter?
Reflow on a new emitter on the existing star or do you use a diffrent PCB?






Benny

I use the PCB that the UV was on but I had to thin it and trim it. Takes forever with one hand and a vise

 

[MorpheusT1]

Got it :thumbsup:


Is there any way these leds will fit on the original Star if i reflow?
Seems to be the easy way out if it would work.


Fiddle work is a PITA
Even with two hands on small parts like that.

 

[CM]

I am not the new owner of this light.
But i wish...:nana:

Those Sense resistors are waay to small for me to fiddle with,ive broken my share with my 4 thumbs.

So these buggers are only seeing like 300mA?
Pretty bright regardless.

How do you guys go about to swap the emitter?
Reflow on a new emitter on the existing star or do you use a diffrent PCB?






Benny

The one I measured is about 400mA but that's subject to a fair amount of measurement error. At the claimed 130 lumens out the front, it's about right. Based on the output, I would say that the sample I had was about 100 lumens, take it with a big grain of salt. The UV LED drive is compatible with the EX10 circuit.

I use the PCB that the UV was on but I had to thin it and trim it. Takes forever with one hand and a vise

 

[darkzero]

I would really like to know what the light is rated, there's nothing listed in the specs.

I really think the light is putting out close to 500ma cause it sure looks like it. I measure only 314ma but it surely looks brighter than that I would guess.

As CM mentioned, I'm sure there's a fair amount of measurement error or difference in accuracy. Chimo gave me the formula: I=vfb/R. I measured 0.047v for feed back voltage at the sense resistor on max. So 0.047/.15 = .313333. I did measure .31A at the emitter. With a .10 resistor I measured .45A at the emitter, calculations gives .47. I now have stacked resistors for a parallel resistance of 0.09 but I'm not getting over .47A, calculations give .52A.

Now I don't have a Fluke or anything but my meter is fairly decent & it's not some HF junk. I hope others can take readings off theirs & verify.

 

[CM]

I would really like to know what the light is rated, there's nothing listed in the specs.

I really think the light is putting out close to 500ma cause it sure looks like it. I measure only 314ma but it surely looks brighter than that I would guess.

As CM mentioned, I'm sure there's a fair amount of measurement error or difference in accuracy. Chimo gave me the formula: I=vfb/R. I measured 0.047v for feed back voltage at the sense resistor on max. So 0.047/.15 = .313333. I did measure .31A at the emitter. With a .10 resistor I measured .45A at the emitter, calculations gives .47. I now have stacked resistors for a parallel resistance of 0.09 but I'm not getting over .47A, calculations give .52A.

Now I don't have a Fluke or anything but my meter is fairly decent & it's not some HF junk. I hope others can take readings off theirs & verify.

Your results are pretty consistent. I need to get another unit to take several measurements with to see how well they vary from unit to unit. Thanks for sharing the data.

 

[koala]

My unit puts out about 610mA at the LED. Input voltage 2.750v. Measured with a 0.02ohm sense resistor in series with the Cree.

Max Output drops to 530mA when input voltage is lowered to 1.25v. Hope this helps.

 

[CM]

My unit puts out about 610mA at the LED. Input voltage 2.750v. Measured with a 0.02ohm sense resistor in series with the Cree.

Max Output drops to 530mA when input voltage is lowered to 1.25v. Hope this helps.

Thanks, it adds another data point. Looks like the measured current is all over the map. If I can only figure out what is the SOT23-5 part that has the marking removed, I can figure out the design.

 

[darkzero]

My unit puts out about 610mA at the LED. Input voltage 2.750v. Measured with a 0.02ohm sense resistor in series with the Cree.

Max Output drops to 530mA when input voltage is lowered to 1.25v. Hope this helps.

Thank you. Can you tell me what I'm doing wrong in my calculations? When I measure at the emitter I only get 300ish ma. I don't see how I could do that wrong but the current measured matches what the formula that was given to me gives. I got 0.047v as feedback voltage at the R150 resistor.

 

[d1dd1]

They are also available here:
http://www.led-tech.de/en/High-Powe...eries/CREE-XL-7090-Emitter-LT-982_120_79.html

 

[Ty_Bower]

The Terralux Ministar UV was supposed to have the Cree 7090UV in it. There's a note somewhere in a thread about the discontinuation of the part. You can read some here:
https://www.candlepowerforums.com/threads/130136

 

[MorpheusT1]

Just modded mine with a R2 Cree.
Much better tint.


Thanks for the inspiration DarkZero and CM.

I may need to redo it though..looks messy in there after ive been about..lol.


Benny

 

[CM]

Thank you. Can you tell me what I'm doing wrong in my calculations? When I measure at the emitter I only get 300ish ma. I don't see how I could do that wrong but the current measured matches what the formula that was given to me gives. I got 0.047v as feedback voltage at the R150 resistor.

Are you sure you measured with the light on high? It doesn't appear that there's anything wrong with what you're doing. The only other possible issue is that we are talking very small voltages (47mV) which is sometimes tricky to measure precisely.

 

[koala]

I tried a different emitter today, a Q2J which I use for circuit testing, I'm getting only 7.7mV across the 0.02ohm 0.1% resistor. That's 385mA at the LED at 3.437v which makes 1.323W.

I went back to the original Cree again to verify the test, I got 12.1mV, that's 605mA across the LED at 3.292v. That makes 1.991W. This time the little Cree star was mounted on a huge heatsink. I could see the reading increase slowly, due to the heat. The feedback voltage across the 0.15ohm resistor was 93.43mV.

Measurements were taken with fluke8840 and hp3468. Power from a HP E3640A linear power supply.

So yeah your reading is correct, it's just the Nitecore circuit is not current fixed? In this case, the max current that could flow through the LED depends on the forward voltage of the LED.

I have no doubt about correctness of chimo's recipy. But, I am not so sure about the tolerance of the on board R150 resistor. It could be plus minus 1%, 5% or 10%. So need include those values.

Thank you. Can you tell me what I'm doing wrong in my calculations? When I measure at the emitter I only get 300ish ma. I don't see how I could do that wrong but the current measured matches what the formula that was given to me gives. I got 0.047v as feedback voltage at the R150 resistor.

I also discovered something interesting. Max output is limited to 630mA at input voltage below 3.80v. Once input voltage goes beyond 3.80v, the output will increase along with the input voltage. My Cree hit 1A at input voltage of [email protected].

 

[CM]

...I also discovered something interesting. Max output is limited to 630mA at input voltage below 3.80v. Once input voltage goes beyond 3.80v, the output will increase along with the input voltage. My Cree hit 1A at input voltage of [email protected].

Sounds like the circuit is strictly a boost converter. The way I determine what kind of converter a light uses is to plot input voltage vs. current (no need to even look at what's going on with the LED) If the current drops and then increases as input voltage increases then the circuit is boost only. If it continues to drop as input voltage increases, then it is buck boost. I will confirm later and do a plot.

My suspicion is that it is boost only and that these runtime plots people have posted with RCR's just means that RCR's drop enough under load to make it appear the light is regulating. And if it isn't, the high current drawn initially will soon sag the RCR voltage so that it still appears like the light is regulating.

Thanks Koala for posting your data.

I think we've gone totally off topic. Perhaps I should start another thread on the circuit in the flashlight electronics section and post a continuation from here?

 

[TranquillityBase]

Great mod CM:twothumbs

OT...What label printer did the yellow warning label come from?

Thanks,
Scott

 

[CM]

Great mod CM:twothumbs

OT...What label printer did the yellow warning label come from?

Thanks,
Scott

Kapton tape over standard letter paper

Please continue circuit discussion here:

https://www.candlepowerforums.com/posts/2560590#post2560590

Otherwise, continue UV discussion at this thread.

Thanks

 

[koala]

Kapton over paper? Very attractive indeed .

You might want to edit the link...

Kapton tape over standard letter paper

Thanks

 

[DUQ]

Where's the bath room beam shots :green: Great mod. I need to get a UV light!

 

[CM]

Kapton over paper? Very attractive indeed .

You might want to edit the link...

Yep, I'm all about "poor man's..." solutions :nana:

Link fixed. Sorry 'bout that.