DD light engine?

DD light engine - updated with pictures!

Sorry if this is a dumb question, but has anyone has done a direct drive light engine?

I was playing today with an UX1L star in my bench and got about:

800mA on a charged 4.2V RC123 cell
790mA on a charged 4.2V PILA168S cell
820mA on a charged 4.2V bare 16750 cell
940mA on a charged 4.2V bare 18650 2400mAH cell

With these numbers, who needs a regulator? /ubbthreads/images/graemlins/wink.gif

So seriously, besides the obvious drop with time due to no regulation, has anyone done this? I must say I am really tempted /ubbthreads/images/graemlins/evilgrin07.gif

Will

Go for it bud! /ubbthreads/images/graemlins/grin.gif

Yes. I've done many of them with TWOK and even TWOJ, and they're awesome. No flicker on "low" either. /ubbthreads/images/graemlins/smile.gif I highly recommend them for a super-bright and efficient setup... and cheaper than using a driver, of course.

If I remember correctly, I was seeing 900mA to the emitter with an R123 and TWOJ.

Just do not make the same mistake I made early on with DD and a single R-CR123.

The LED just sucked the juice right out of the cell and damaged the cell beyond repair. Unprotected cells need some sort of cut off at around 2.6 volts. If you take these unprotected cells below that , they are damaged.

Cool - thanks to all. How did you guys solved the lack of a positive terminal on the LE? What did you guys used to make a new terminal for the positive side of the battery?

Will

[ QUOTE ]
I was seeing 900mA to the emitter with an R123 and TWOJ.


[/ QUOTE ]

Isn't that a bit low when looking at a J-bin? IIRC the LionCubs were J-bins and drew about or more than 1.5A on high on 1xR123 ... ??

bernie

current draw will depend on final vf, factor aprox. .3V drop

here's aprox what I've been getting DD with 1x R123 li-ion

L bin = 900 milliamps
K bin = 1.2 amps
J bin = 1.5 amps
H bin = 1.75 amps
I bin = 2 amps

luxeon lottery applies to vf, output and tint. best method of DD off single li-ion is to match VF with chemistry under load. allow for VF when factoring this. vf drop can occur very quickly.

most dangerous is when using true Hbin on lower range. which will draw aprox 1.85amps, after vf drop occurs. luxeon will draw 2+ amps and will nova shortly after.

all li-ions unless outfitted with protection circuits will discharge at huge currents. bare R123 will discharge at 15+ amps.

have a discharge rig in the works and hopefully will be able to report actual discharge rates for larger cells like 18650's.

Thanks so much cy - great information /ubbthreads/images/graemlins/bowdown.gif

Today I was warned about the vf change after the first 50-100 hours, which I was not taking into account until now.

Overall, I am not scared about the DD for the LE, but I will proceed more cautiously /ubbthreads/images/graemlins/wink.gif

Thanks again,

Will

Will,
Be Afraid, Be very Afraid!!! /ubbthreads/images/graemlins/nana.gif

OK, OK, maybe I am a "little" bit afraid /ubbthreads/images/graemlins/aaa.gif

Will

My 2 aleph light engines are DD with Pila battery and TW0J.

Burn baby burn /ubbthreads/images/graemlins/grin.gif


Pablo

Bernie and Cy - Was going off my rusty memory! I know I measured *something* at 900mA. Was likely an L bin. I'm assuming that the numbers Cy listed are with the battery fresh off the charger. Remember that the current will lower as the battery drains. Sure has hell is bright at first though!

As for anode contact... you either find a friendly lathe guy who can turn you a delrin spacer and a brass nubbin... or you take a fried BB/NG/DB driver, scrape all the components off, and just glue it down to the bottom of the can as usual - running a wire up from the Anode button. The bad news is that I have plenty of this type of board to work with. /ubbthreads/images/graemlins/frown.gif

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The bad news is that I have plenty of this type of board to work with. /ubbthreads/images/graemlins/frown.gif

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/ubbthreads/images/graemlins/crackup.gif

Funny! Me too! I also have the option of making my own contact assembly.

Will, the price of admission is bench mistakes, some craftsmanship or paying someone with the time and equipment to make a contact assy. for you. Gots to mod bud! /ubbthreads/images/graemlins/nana.gif

Well Don, and Darell, since you openned this can of worms... you should know that my "test" U bin 3W was actually a perfect, new UX1L star that I was using to replace my sorry-*** "S" bin on a BugOutWear 3W module. "Unfortunately" I was not carefull enough while I was filing the edges of the star (once assmbled) and dropped the whole assembly onto the hard concrete floor ... To my horror, the plastic dome cracked right in the middle, from side to side - instantly ruined from ever developing a nice beam. In no time I had $35-40 down the drain /ubbthreads/images/graemlins/crazy.gif

Interestingly enough, the darned little zucker still lights up with no problem, so every time I want to test something, I use my "damaged" unit as a guinea pig /ubbthreads/images/graemlins/smile.gif. I am sure that it was my first time, it will "certainly" will not be my last "accident" /ubbthreads/images/graemlins/crackup.gif

Come to think of it, maybe one of the leftover parts from the BugOutWear could be re-used or modified to give me the positive contact I need for the battery ... time to go into my work bench tonight /ubbthreads/images/graemlins/wink.gif

Will

/ubbthreads/images/graemlins/thumbsup.gif

Will, over two years ago, I had two hand built proto drivers from Wayne that had hall switches on them and were honest to goodness two stage, constant current drivers. I had modified a couple E series hosts for these and was in final build and testing I killed one during assembly and the other after about a minute of actual and functioning operation. In retrosepect, I think it was the soldering tip contacting the arctic silver grease that likely turned it into an imprompto solder paste, that took out the final proto. Magnet in rotating collar on the head and full nine yards. We were way ahead of the game but I took care of that! /ubbthreads/images/graemlins/icon15.gif If you are going to make an omelette..........

Ouch - a prototype /ubbthreads/images/graemlins/rant.gif

I hope Wayne was not too mad /ubbthreads/images/graemlins/whoopin.gif

At least I can always go to Fred (PhotonFanatic) and order a new UX1L (when he has them). Yet more proof that we learn by making mistakes - sometimes costly ones /ubbthreads/images/graemlins/icon15.gif

At any rate, I started work on the DD module last night. Instead of a hollow core, I am using one of the MiniM*G cooper DD heat sinks from ViRen, which diameter-wise happens to fit perfectly inside the can. I need to trim the cooper piece heigh-wise, but this should give the emiter a larger heat mass, which can't hurt /ubbthreads/images/graemlins/wink.gif. I will post some pictures later on.

Will

[ QUOTE ]
over two years ago, I had two hand built proto drivers from Wayne that had hall switches on them

[/ QUOTE ]

WOW /ubbthreads/images/graemlins/ooo.gif
THAT would heve made the news two years ago if it had worked out ... /ubbthreads/images/graemlins/cool.gif

bernie

OK guys, here is what I have done so far:

Instead of a hollow core, I decided to use on the cooper heat-sinks that ViRen at the CPF's sells for DD on MiniM*gs, and it happens that diameter wise it fits perfect inside the module, although I had to trim it heigh-wise:



In order to give it an extra mechanical bond, I took the same very fine cooper particles I got while filling the heat sink by hand and mixed them with AA epoxy. I simply used a wire to keep epoxy out of the wholes. Not only the total thermal mass is larger, but it "feels" solid in the hand . It is really hard to see from the pictures, but both the can and the cooper module have cuts on thier contact surfaces so that the AA epoxy will create a pretty strong mechanical contact on all surfaces - this puppy is not coming apart while screwing in/out of the Aleph head!:







Now I had to figure out a way to create a new positive point for the battery and of course I need to electrically isolate it from the cooper and the rest of the module:






For the actual positive contact point, I am using the metal end of a battery holder:







Now, if you notice on that very last picture, the new positive contact point (not glued yet) will actually be slightly above the surface on the back of the module. I don't know if this will be OK or not as I have never seem any hard numbers on how hight that positive contact should be. Does anyone know?

Will