Advice? 190Lu R/O on a Hotlips driven at 1.5A?

Hi guys,

I'm coming to you as a hot wire guy looking to do a little something in the LED world.

I've got a 190Lu G2GH Lux3 LED star coming in and I'd like to max it out on a Hotlips. The host would be an aluminum teargas shell and I've got 4 x 1/2D high current 4Ah NIMH cells to drive it with.

I'm wondering what driver I should use and if emitter mounting on the Hotlips is the best way to go. The spent teargas shell is about the same diameter as a MagD and when I tried it, a Hotlips dropped right in. and held on the front flange.

That leaves the question of a head, optic or reflector.

Any advice would be appreciated. Alternatively, I'd offer the LED and teargas shell to someone who might want to tackle this off-beat project. Aside from the butternut squash, this would be the strangest host I've considered.

Thanks!

Wilkey

Wilkey,
You will have to remove the emitter from the star if you want to mount it on the hotlips. I think that the sandwiche shoppe can modify a downboy to about 1.4 amps for you. The head,reflector/optic and switch will be a project in and of itself. As will be the attachment of those items to the case such that you can get to the batterys.

Dave

The Lux III R/O is a difficult beast to tame, optically. Using a mag reflector, the spot is about twice the diameter as that of a Lux I/III - it's more akin to attempting to focus a Luxeon V...in fact, I'd say it's a bit more difficult, since the Lux V acts like a 2D plane, whereas the R/O Lux III emission area has some volume, so with a reflector, there isn't an immediately obvious point where it snaps into focus.

I might try to take beamshots of a R/O with various optics...

1) You will need to make sure that if you use EITHER a Star, or Emitter, than the heatsink does not contact a negative part of the light, or at the very least, the slug of the emitter/star board doesn't touch negative metal. Or you will melt the bond wire in it.

2) Ok, now that the important part is out of the way, Next would be power. You've decided on a power source, which is 4 NiMH. You'll need a buck/stepdown driver of course. A Downboy1400 or 1500 would work fine. BUT you'll have to be carefull as these R/O will pull the NiMH well below the self discharge and ruin them!! So... you'll have to keep track of that. Perhaps an LED (3mm/5mm) on the side or a couple that go on or off when you get to the Danger point of discharging the batteries. That sounds cool. When the batteries are .93volts time to recharge they'd add up to 3.72volts which the R/O would try to pull more than 1.4amps still!! Same problem with 3 NiMH too.

You COULD go with 2 NiMH cells, and a boost circuit. That would be 1.83 volts when discharged.. Not sure if any circuits turn off at that voltage or not. But you will need to hook up 2 BB750's in parallel for example, becuase the current through just one set for the full current would exceed the input current.

3) As far as optics, this is as large as a 5W die as far as LxW goes, and taller H wise. So it's got a large multisurface emitting area. Best to go with a deepest reflector you can try. Or!! get an Apsyerical lens to focus it best. I think that would be good, and look cool on the top of the cartridge. Now I know a decent amount of light would still be scattered away from the lens, so perhaps a 17mm or cutdown reflector then the lens? If you light up the R/O star on a table notice how the light is shined on the table all around it, like light is being fired a full 180 degrees from the emitter...

In Closing, I'd say go with less batts to fit the optics in the head. If the Hotlips is snug fit, then grind off the lip and push it down to the right height to fit the Lens on the top. Find a way to open it from the bottom to change the batts, or put in a charging jack. So it would look like a real large round of some type, only the slug would be the asphyrical lens! heh.

Hope this helps on some points, sounds really neat.

-Isaac

The primary challenge in optimizing the R/O is heat removal. Prior information, also consistent with the Lumileds R/O data sheet, shows that these are MUCH more temperature sensitive than the white Lux III - which is already pretty sensitive to rolling off earlier than expected.

In a perfect world, you would have at least 9 in square of exposed surface area to deal with heat removal.

The NiMH cells you use are so flat running at this current draw that 3 x can easily meet your needs. In fact, you could almost resistor it with the performance I have seen from your cells - and 3 x 1.2 V is only a few tenths of a volt over the LED Vf - easy to deal with.

I think that georges80 / taskled is working on high power current drivers - not certain of the status.

I can send over a couple bent stars for a buck just so you know how far and how to do it to get at the emitter.
I would kinda lean toward using 2 batteries direct drive at 1st and see what you get.

Good luck. /ubbthreads/images/graemlins/smile.gif

Downboy should work fine. I know they can make them 1400mA. I'm not sure about 1500mA. That should tame the heat enough using a hotlips heatsink. Don't worry about the batteries. Just run some test to see what the safe runtime is with them at normal voltages.

You could always use pila's or protected R123's and then you don't have to worry about voltage at all. /ubbthreads/images/graemlins/smile.gif

Jeff

Two pilas in parallel with a downboy and/or LDO linear regulator would work well. You wouldn't need to worry about low voltage cutoff. In fact, I don't think the downBoys would work too well - I think they need at least 0.4V+Vf to stay in regulation - whereas an LDO regulator will be in regulation at 0.1V+Vf.

Once again, Ginseng comes up with the unusual!!

Me, not knowing any better, I dropped my red/orange into a Nuwai Q3 and wow, that sucker is bright!

Good luck, Wilkey!

Bill

Hi all,

Thanks for the great advice. I'm taking it all to heart and I'm going to recast the project in a totally new way. The emphasis will be on applying technology to maximize the current applied while maintaining thermal regulation. I'll let the form factor of the power solution drive the optical system.

Thanks again!

Wilkey

So does that mean you're looking at going for a different host?

Not necessarily. I'm trying to figure out how to get the cooling components in therer and still provide 12VDC to power it. We'll see.

Wilkey

12volt?!? huh? /ubbthreads/images/graemlins/thinking.gif

12V to plug into a car's power outlet?