Can someone take a look at this and let me know what to do?

This is a Lux5 star emitter from my pentagonlight l3 which is a 9V model using 3 lithium primaries.

I was hoping to upgrade the emitter with something more "throwy" and a little brighter.

Can i pop the EMITTER off of the star and replace it with a SSCp4?? or is all of that curcuitry specific to the lux5?

No, it won't work. You'll will fry your P4.
You need to get larger resistor to drop from 9V to ~3.5V. There is a HUGE loss (>60%).

Get yourself a buck converter (downboy or nFlex) for better efficiency.

modamag said:

No, it won't work. You'll will fry your P4.
You need to get larger resistor to drop from 9V to ~3.5V. There is a HUGE loss (>60%).

Get yourself a buck converter (downboy or nFlex) for better efficiency.

Click to expand...

ok, which one should i be looking at? i was checking out the sandwich shoppe but there are so many of them, and i dont know enough for all of the numbers to make sense.

aml, besides the advice of modamag, you can measure the voltage at the Led. Then unsolder the star and take a look to the backside. There you should find the binning. If not, you'll have the datas you've measured.
You can get a premium LuxV with better binning and mount it back to the heatsink. This way I improved my LuxV light. The stock star was a V _ _ T bin and I replaced a WX0S bin. Twice the output, much better throw.
That would be the easiest way.

Good luck and best regards

_____
Tom

"If" there is space available, get yourself a Downboy 750mA.

modamag said:

No, it won't work. You'll will fry your P4.
You need to get larger resistor to drop from 9V to ~3.5V. There is a HUGE loss (>60%).

Get yourself a buck converter (downboy or nFlex) for better efficiency.

Click to expand...

I've modded about a dozen lights by direct replacement of a Luxeon emitter with a Seoul P4. The forward voltage is about the same at the same current, so I've never had to modify the driver circuitry. This light is obviously regulated, which means that the LED is being fed with a relatively constant current regardless of the forward voltage. I don't understand why you're saying the P4 would be fried -- please explain.

Incidentally, in all the Lux stars I've seen, the LED mounting pad is electrically isolated so it's not even necessary to insulate the P4 from the pad.

c_c

Curious_character said:

I've modded about a dozen lights by direct replacement of a Luxeon emitter with a Seoul P4. The forward voltage is about the same at the same current, so I've never had to modify the driver circuitry. This light is obviously regulated, which means that the LED is being fed with a relatively constant current regardless of the forward voltage. I don't understand why you're saying the P4 would be fried -- please explain.

Incidentally, in all the Lux stars I've seen, the LED mounting pad is electrically isolated so it's not even necessary to insulate the P4 from the pad.

c_c

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The LED would INSTANTLY FRY. A Cree or Seoul can replace a Lux III as the Forward Voltage is compatible. The LuxV has DOUBLE the Forward Voltage. Also this light is not regulated the custom board that has the LuxIII mounted clearly has SMT resistors

Mac

I think i would have to machine the module to fit a downboy board in there.

are there any emitters that would be a direct drop in replacement in that star?? any of the k2's??

im gonna get some measurements on the output voltage and mA of that star tomorrow, if i can find my multitester.

Curious_character said:

I've modded about a dozen lights by direct replacement of a Luxeon emitter with a Seoul P4. The forward voltage is about the same at the same current, so I've never had to modify the driver circuitry. This light is obviously regulated, which means that the LED is being fed with a relatively constant current regardless of the forward voltage. I don't understand why you're saying the P4 would be fried -- please explain.

Incidentally, in all the Lux stars I've seen, the LED mounting pad is electrically isolated so it's not even necessary to insulate the P4 from the pad.

c_c

Click to expand...

The L3 is a Lux V light, not a Lux III. It's sending too much voltage for a Cree or SSC.

I just want to apologize to you folks......ive been trying to read about this stuff as much as possible. Im just not getting it.....im good with mechanical stuff, and soldering and whatnot....but i swear i just need someone to hold my hand through the technical stuff.

I PROMISE that im not dumb......but i think that i irreversibly used up most of my brain in Dental School. Im afraid that if i learn this stuff, ill forget how to floss.

aml said:

I think i would have to machine the module to fit a downboy board in there.

are there any emitters that would be a direct drop in replacement in that star?? any of the k2's??

im gonna get some measurements on the output voltage and mA of that star tomorrow, if i can find my multitester.

Click to expand...

You'd need to get a W*** or X*** Lux V for a direct replacement, the best of which tend to be pretty pricey. It might be cheaper and less frustrating to just get something like the M1 Hunter. You could still sell the L3 for close to what the M1 costs, I would think.

aml said:

I just want to apologize to you folks......ive been trying to read about this stuff as much as possible. Im just not getting it.....im good with mechanical stuff, and soldering and whatnot....but i swear i just need someone to hold my hand through the technical stuff.

I PROMISE that im not dumb......but i think that i irreversibly used up most of my brain in Dental School. Im afraid that if i learn this stuff, ill forget how to floss.

Click to expand...

No need to appologize. We all started somewhere. I killed two R/O Lux IIIs before I realized they were grounded different than white Lux IIIs.

cratz2 said:

You'd need to get a W*** or X*** Lux V for a direct replacement, the best of which tend to be pretty pricey. It might be cheaper and less frustrating to just get something like the M1 Hunter. You could still sell the L3 for close to what the M1 costs, I would think.

Click to expand...

where would i go to find these, and how pricey are we talking?

and will a different lux5 REALLY make THAT much of a difference?? i just figured a 5 watt was a 5 watt was a 5 watt.

aml, no need appologize. We're all here to have fun and learn something while at it.

Anyone of us can learn sooner or later. Either thru reading numerous threads and posting questions or by hands-on experience (fry couple emitters here and there).

Welcome to CPF! If we "forgot" to shown you the welcome mat before. :wave:

*image courtesy of B@rt

As for your light. The DB750 (Downboy 750mA) is probably small enough to sit between the reflector and heatsink pad. Just a thought.

BTW: Congrats on dental school. Some of my weirdest friends are dentist.

modamag said:

aml, no need appologize. We're all here to have fun and learn something while at it.

Anyone of us can learn sooner or later. Either thru reading numerous threads and posting questions or by hands-on experience (fry couple emitters here and there).

Welcome to CPF! If we "forgot" to shown you the welcome mat before. :wave:

*image courtesy of B@rt

As for your light. The DB750 (Downboy 750mA) is probably small enough to sit between the reflector and heatsink pad. Just a thought.

BTW: Congrats on dental school. Some of my weirdest friends are dentist.

Click to expand...

i think that the downboy will fit in there, but i also need to mount the emitter to a heatsink do i not? im not sure i have room for the DB AND the heatsink.....unless i lathe out the little cup shown in the pic, OR take some off the bottom of the reflector...but im afraid to take too much off, for fear it will change the focus of the beam too much.

Welcome to CPF. Hope you have a hammer, you'll be using it soon on your piggy-bank.

Nice-binned LuxV emtiters go for $30+.
However, here is my advice for modding this unit:
1) Either Cree or SSC P4 (or higher) binned emiter with low forward voltage in the 3.0v~3.6v range.
Since this is a 3-cell light, instead of using 1 or 2 cells with a dummy for lower-voltage, switch to using 2x17500 (same height, 1mm wider, check this).
Supply-voltage would then be 7.2v (or more).
2) For the emitter to handle this high voltage, use a Downboy at the desired drive-leverl. Something like 750mA would be nice, is you have good heatsinking.

If you would replace the complete star in your light, you would loose any regulation since I think the smt components on the star do "some" kind of regulation. Replacing an emitter on the star isdoable, but not easy, but then you would also need to replace the emitter with one that runs at that same voltage (maybe 6v?).

If you are good with machining, getting a DB750 (Downboy 750mA) to fit would be no problem at all. Maybe no machining at all. This converer is only 0.55" in diameter and maybe 5mm high. Max input-voltage 16v.
Downboy 750 sales and specs here: http://theledguy.chainreactionweb.com/product_info.php?&products_id=495
With 2x 17500, these will run your led in regulation LOOOOONG

Also, when mounting the new led, consider using a custom plate/heatsink.

Let me know if this is something you would like to work out further or if you had other requirements.

Also, can you post more pics of the light, I would like to see the head and below the current emitter-board. Curious what reflector is used and what it looks like.

Cheers mate !

As far as picking a current level at which to run a Cree orSSC, I'd also have look at Newbie's Chart. Figuring your L3 is probably somewhere around 75 to 90 Lumens, a Cree at only 400mA is going to be brighter than the stock LuX V. 750mA should be somewhere over 130 Lumens.

Also keep in mind that the Cree he used for that chart was a P3 while P4s are plenty common and hopefully, Q2s and Q3s will be available in small quantities before too long.

Thanks for the info. I didn't realize that the Lux 5 had such a high forward voltage -- guess I've been lucky that I haven't encountered one yet. A good current regulator shouldn't care about the forward voltage, but those are probably rare in flashlights.

(Edit: I just looked at the Lux 5 data sheet, and see why I haven't run across one -- they don't come in white, and I've been working only with white LEDs.)

c_c

Curious_character said:

Thanks for the info. I didn't realize that the Lux 5 had such a high forward voltage -- guess I've been lucky that I haven't encountered one yet. A good current regulator shouldn't care about the forward voltage, but those are probably rare in flashlights.

(Edit: I just looked at the Lux 5 data sheet, and see why I haven't run across one -- they don't come in white, and I've been working only with white LEDs.)

c_c

Click to expand...

The Lux V's come in all the colors including white. Check out Photofanatic's sale thread. Also most driver boards in flashlights are either a Buck (down) converters or Boost converters.

Mac

Yes LuxV comes in white, just that lumileds call it "Luxeon V Portable"...