I need some low Vf Luxeons...

[pedalinbob]

im going to build some direct drive 2-cell (lithium 1.5vx2) brinkmanns for some family and friends. i thought about simply getting them a MM or BB, but they want me to build them myself.

well, allrightythen.

i finally decided to learn the luxeon bin structure, and realize that having a low forward voltage rank would really help to brighten them up.

i see where Dat2zip has some Q4H stars--those have a low Vf, right?

here are the questions: what 1w rank and type (bare emitter or star) would you recommend for this application?

(i was thinking that an O, P, or Q flux, with 2, 3, or 4 tint, and as low Vf as i can find--perhaps H, I or J. i think a bare emitter might work well, but i am unsure)

where can i purchase some luxeons in the desired rank/type?

any suggestions for a relatively novice modder?

Bob

 

[CM]

pedalinbob,

You might want to read about Mr Bulk's commentary on bin ratings. I use them as a guide, more like a wish. Your best bet is to buy several and test them all for suitability to the task at hand. Wayne (dat2zip) has some for sale and they're sorted by bin rank. You could get a MM or BB and still build them yourself, not sure what you mean by that. I personally prefer some type of regulation as it removes the LED's Vf from the equation. Plus you get a constant output (at least with a BB) through the useful life of the batteries.

CM

 

[shiftd]

Um CM, I don't really agree with that, but please forgive me if i am wrong. The Vf of the lux is not really removed from the equation if you use BB or MM. Provided all things being equal, the low Vf will appear brighter than the high Vf one, even if you are using BB.

I think to make the DD lux, you will need emitter as they will make your job one step easier. One good source for luxs is indeed Dat's shoppe and you get to choose your bin. I suggest get the 3 or 4 color binned one, with H or J Vf. Because you are gonna sell this to a fellow non-flashaholic, i think you can get away with P or Q lux, so you won't have to spend a fortune to get a good binned lux. I suggest drop wayne an email and ask what bin that he has on stock.

good luck on your modding /ubbthreads/images/graemlins/grin.gif

 

[tvodrd]

shiftd,

I have to disagree a little myself /ubbthreads/images/graemlins/grin.gif . BBs are constant current drivers- they drive whatever voltage is necessary to produce their rated current. However, using a BB with a lower Vf LS results in more lumens/watt, but actually pushes less watts for equal brightness (leaving out the rest of the lottery /ubbthreads/images/graemlins/grin.gif .)

pedalinbob,

CM is right on the binning being somewhat of a "wish list." I have a couple of the Q4Hs from Wayne, and both pull ~210 mA from a fresh 123 (3V) and IMO would be fine for your application. They are towards the "blueish."

Larry

 

[NightStorm]

pedalinbob,

I concur with tvodrd. Lumiled's voltage binning is roughly a 1/4 range. In the case of H-bined his would be 3.03v to 3.27v. An emitter with a Vf towards the lower end of this range may drive nicely @ 3v, while an emitter towards the high end of this range may only pull 80ma @ 3v (I have a R2H that is like this). Now the question is....would your friends and family mind amber, red-orange or red colored lights? These emitters generally have lower Vfs (in the E,F,G bins). The problem lies in finding anyone that actually sorts their colored emitters. My apologies for raining on you parade, but I thought you should know.

Dan

 

[shiftd]

ah ya Tvodrd,
I agree with what you said. Dang, what am i saying. /ubbthreads/images/graemlins/twakfl.gif
The difference in brightness was caused by the first part of the bin. /ubbthreads/images/graemlins/banghead.gif /ubbthreads/images/graemlins/ohgeez.gif

 

[tvodrd]

Hi Shiftd,

PercaDan brought-up a really good point! I have my first non-white, a red/orange, no clue as to Vin bin, assembly in a DD CR2. It is blazing bright! I have a "green" I am dying to try behind an optic. In indoor lighting, the diode is like it has a 1" sphere of some kind of "speckles" surrounding it! The reds and greens seem to have lower Vfs across the board. (Their color usefulness has been discussed in other threads /ubbthreads/images/graemlins/grin.gif ,) Can't deny they are impressive! Better LSs are in the "pipe" and hopefully we will have the first opportunity to exploit them. /ubbthreads/images/graemlins/grin.gif

Larry

 

[NightStorm]

Right now, I shoving a low G-binned amber HD into an Infinity for a DD "Luxi" (using one of the cells out of a CRV3). It'll be quite the lil' hand-warmer when I'm done. /ubbthreads/images/graemlins/grin.gif

Dan

<EDIT> Being as this emitter came off a mid 2002 Star/O, I'm guessing that a more recent bin code for it would be a high P or low Q on flux, 3 or 4 on hue (its amber-amber, 1 would be greenish-yellow), low G on volts (2.79v - 3.03v, confirmed 350ma @ 2.82v) with an A qualifier for Amber. Just thought ya' might like to know.

 

[pedalinbob]

sooo...if i end up with a nice h-binned luxeon (white), the range being 3.03-3.27v, it THEORETICALLY will run rather nicely direct drive from 2 lithium aa. (i have 10 lithium aa's that i just measured: they are all 1.75v each. that will give 3.5v for two.)

i know, the bin is only an approximation of performance...i cant wait for luxeon/nichia/whoever to get the process down perfectly so we wont have to worry about all this binning stuff.
even better yet: make some led's that have vf of perhaps 2.5v.

thanks for all the info--i knew you folks would come through.

i am still thinking i should just get some MM or BB boards, some emitters, and solder them up. they will have excellent output, and i can certainly state that i built 'em!

Bob

 

[NightStorm]

I just tried 2 Energizer E2s with a R2H and got 265ma @ 3.02v. The individual cell voltages were 1.68 (new) and 1.66 (used for maybe 20 minutes in an Infinity Ultra). While the R2H would still beat an O flux-binned LD ran at spec, it wasn't delivering its full potential. If you're still insistent on using white emitters, you probably better off using some of zippy's sandwiches, as low Vf white emitters seem to be as rare as X binned 5 watts. Later.

Dan

 

[shiftd]

Or you can go 3 cell (using Brinkmann 3AA body) and DD any white lux, no matter the Vf at (more than) full spec

 

[NightStorm]

Or what shifty said. /ubbthreads/images/graemlins/grin.gif

Dan

 

[pedalinbob]

ooohhh...i LOVE DD on 3 1.5v cells--i have built several of these mods. incredibly bright and very simple.

thanks everyone...now, im off to the lab...

Bob

 

[shiftd]

/ubbthreads/images/graemlins/grin.gif
no problem
hey, we are here to help you. /ubbthreads/images/graemlins/grin.gif

 

[NightStorm]

Well, my job's done here. Time to ride off into the sunset. /ubbthreads/images/graemlins/grin.gif

Dan

 

[AilSnail]

I tried two of wayne's Q4H LD; DD from 2 alk AA, they were fine, though a tad green. The three R2H HD's were barely visible in the same situation.