Trouble w/ LuxV

I''ve built a light with a WWOS LuxV, DB833(.12-.12), and an IMS27 reflector.

when compared to a brinkmann maxfire(65lumen incan) it loses sorely, though both are running on freshly recharged 123's (3.6V hot off the charger, 650mAh)

the light's body registers roughly 3 ohms; it that enough to dim a LuxV to below 60 lumens??



am I missing something?

It cant be getting all the votltage.

you have a DownBoy convertor, how much voltage are you supplying it?
with a Lux V, u need more than 6 volts for the convertor to be working, anything less than 6 volts, u actually need the Badboy convertor
so if you put in 2 rechargeables, hot off the charger should be about 4.2 for each cell, the Downboy should be good till 12 volts IIRC
then it should run in regulation
with just one RCR123, it will not be in regulation and actually be in direct drive, hence it will be less bright
hope this helps
Des

sorry if i wasn't clear, each light is running on 2x123R(3.6x2=7.2Vsource)

ok, narrowing it down
how about the focus of the reflector, is the reflector at the correct height to focus the Lux V properly? the Lux V has 4 dies, compared to a single die from the Lux I or Lux III
you have to adjust the height of the reflector.

also, how are you comparing the two, is it in throw or overall brightness?
are you comparing it on a white wall?

are the two reflectors similar in size? or is the brinkman larger?
the size of the reflectors as well as positioning can affect the output of teh Lux V.

if possible can you post pictures?
wonder how the W bin is in your words "loses sorely" maybe the Lux V could be a rather low lumen one

either that or if you are overdriving the bulb in the brinkman and achieving higher than usual lumens?

sorry bout the barrage of questions, i too am curious as how a W bin could be significantly dimmer
best regards
Des

Forgive me for asking the obvious, but you are running it off of 2 cells, right?Hot off the charger that's 8.4 volts and a nominal 7.4 volts. With that kind of input voltage and a output current draw of only 833 milliamps then you should have regulation for a decent period of time before the battery voltage declines below regulation threshold.
The Downboy is one of the most practical converter boards in use today in that it's tough, durable, and most of all,adjustable up to 1500 millampres and up to 1700 milliampres in 10 minute bursts at your own risk.

The Downboy converter has a floating ground if I remember correctly. Someone correct me if I'm wrong. It has been a long time since I used a Sandwich.

The ground terminal on the board has to be attached to the body of the light. The ground wire is usually done on the inside of the converter where it is not seen. You have to hard wire the converter ground terminal to physically ground on the body or E-can.

Some of the older Downboy converters were defective. The boards had a small amount of flashing along the rim of the converter. That flashing would short circuit the converter board on the body of the light. Simply file, sand or scrape the flashing off the rim of the converter. If you have a newer Downboy then the flashing problem doesn't apply.

The Downboy converters have been very reliable. At 650mA you should have a bright light if the converter is operating properly.

It's a Downboy Revision 3


The IMS27mm reflector is placed perfectly on top of the Luxeon and uses a polycarb lens

the brinkmann has a 26mm reflector, a bit shallower and uses mineral glass

as for output my two tests are 4" from my desk and 10' to the white wall across the room.


the brinkmann scores a blindingly bright hotspot at 4", and "bright" on the wall

the luxV scores a "bright" hotspot at 4" and the equivalent of my lux3(S bin mag) on the wall




the insulated led+ and led- wires go to the luxV which is arctic silver epoxied to the aluminum headsink; which sits inside the aluminum dorcy host. the (bare)GND wire wraps around the heatsink and comes into contact with the flashlight body when it is in place. a spring has been soldiered onto the batt+ plate on the DB.

i'll clean up all the contacts tommorow.

will regular grease work for the contacts?

i've spent around $100 on this project so far(grrrrr burnt up parts) so i wont mind buying some radioshack grease
if it will make the difference

RCatR
i see you have the IMS placed directly on top of the Lux V
try a shim to raise the height of the reflector, i had to do this with my Pr reflectors, it might make a difference
the shim height to raise the reflector is about the thickness of 1 mm give or take
this is the part that is annoying about the Lux V compared to the Lux III
the height of the reflectors has to be increase in the Lux V but for the Lux III, the reflector can just sit on top of the LED
try different shims thickness made from combining business cards,

c'mon guys, more suggestions to help you RCatR,
the man has built his own light already and to have it not perform at this stage is just heartwrenching

Thanks for the support!

This is revision7(?) which uses a [modded]dorcy body as a host. For $30,000/yr you'd think RIT's machine shop would have the taps I need but nooooooooooo, so I went comercial

Just some wild ideas for you to test
- Is there a very good heat path for the heat from the Lux V slug to get to the wall ? The "heat sink" is of course really a "heat spreader" it just moves the heat to the body. If this path is not extremely good - it will dim quickly.
- Is there any chance that you damaged the LED by running it before it was well heat sinked - I have done this more than once. It does not take long - less than 30 seconds sometimes.
- How thick is your heat spreader ? It has to be at least several mm to do any good.

- There might be something funny about how you have wired the battery ground to the heat spreader. Ideally, you would want to insulate the heat slug electrically from the outside world. I have wired it before so that the slug is grounded commonly with the LED ground and battery ground (on a resistored light) but never with the slug electrically tied that way.

In effect, you might have tied the floating ground of the LED to the battery ground.

- Last but not least, the Lux V is nominally a "150 Lumen" LED, but that is only for 25milliseconds. When reality settles in from thermal effects and other losses, I use the "divide by 2" rule" - so I call it a 75 Lumen flashlight.
- Your Brinkman is being over driven I think, which is fine. Instead of it getting 5.5 volts from 2 x primary 123s, you are feeding it nominally 8 volts from 2 x R 123s. It may actually be punching out over 100 Lumens.

- 3 ohms does seem like a lot of resistance to me BTW.

You need to measure the current being drawn by the batteries, and then measure the voltage across the luxeon.

My suspicion is that the 3 ohms of resistance in the body is killing things, and the DB is not running in regulation.

Let say to supply power to the luxeon, normally the DB would draw 500mA. With that 3 ohms, the DB would be getting 1.5V less than expected. So in reality, it's drawing more like 700mA, which reduces the voltage by 2.1V. This really doesn't work either, especially when attempting to supply the load with 800mA, so I don't think that the DB is in regulation at all (I think it also needs like 0.4V of overhead for the regulator). In fact, I'll bet you're only getting like 500mA or less to the luxeon.

But we won't know without some electrical measurements.