input on 3x3 R/O setup

my plan is to use a MOM PTS with 3 LuxIII G2G R/O's in series with a DB1400 powered by 8 AA in a 8AA to 2D configuration. Any input or advice on this build. Its going in a Red 2D host.

Ryan

thats gonna be a helluva lotta r/O light!!!,, should be schweer.

Shane

oy yea i figure somewheres round 550 lumens or so, and since its red/orange its gonna scream!

yep, and it's gonna be painful to look at /ubbthreads/images/graemlins/wink.gif

Are you planning on using NiMH's in it? if so you're probably going to have to bore the body of the Mag out a little depending on your cells of choice.

Shane

will look at both alkies and NiMH to see what works better

Ryan

Hi - nice build idea. That will be one really bright sucker.

I am not really awake yet, so this is kind of dangerous, but I will point out the "risk areas to double check".

The DB is a nice, proven board. I have not had my coffee yet, but the Shoppe is listing boards up to 1000ma, not 1400 - maybe I am forgetting that these can go higher. /ubbthreads/images/graemlins/smile.gif

At 1400ma, the LL data sheet shows a Vf of 3 for that product, giving you a Vf for the 3 = 9 V. For the NiMH setup, you only have approx 8x1.2 V = 9.6 Vin. I cannot remember, the specs on that board, but I kind of like to have at least 1.0 V drop to play with when using a CC board.

Normal alkaline AAs might not work at all, or for long at 1.4 A draw rate. You will definitely want to have the Li enhanced ones.

Heat - If you are running this super light for only 1 minute or so, it will be ok, but if my calculations are correct this morning, you have roughly (9 V x 1.4 A = 12.6 watts) of heat to dissipate through your hand. This light will quickly feel very warm. Of course since you will be able to see everything a long ways away, then maybe it does not have to be on very long. /ubbthreads/images/graemlins/smile.gif

Last, but not least, and this will likely get me some flack, I suggest running at more like 800 - 1000ma. Reason - light output for LEDs drops RAPIDLY as they warm up. I don't claim to be an expert, but my bench experience with (mostly white) is that it is just plain hard to remove that much heat from an LED and drive anything close to that power level. The net effect is that your 1400ma spent (might) give no more light that 1000ma would after 60 seconds.

Of course, for "quick on / off", it will be fine.

Have fun with your project - and buy extra parts, something always seems to break just when you are almost finished.

Harry,

I'll second your underdrive suggestion, especially in this case since it's a red/orange. Luxeons in that color family suffer brightness loss from heat worse than white/blue/green do, due to their materials.

If you allow the flashlight body to get up to 50C (max comfortable for hand holding), then the Tj will be around 92C at 1.4A, for a brightness loss of 60% - so that spec'ed 190 lumens suddenly becomes ~75 lumens.

Instead, if you run it 1A, you'll get about 75% of the spec'ed light as at 1.4A (for about 145 lumens), but given the same thermal scenario, Tj will only be at about 77C, for a brightness loss of about 40%, so that spec'ed 145 lumens is now ~85 lumens.

So given that the flashlight body is going to heat up, you can probably actually get more light (in that scenario) by running those R/O's at lower current.

Thanks for the input on this guys, really helps perhaps i will look into getting a DB1000 then instead. The DB1400 was built from a blank that get the desired current, perhaps I will save it for a single R/O setup. I appreciate the input and will build it into the design.

Ryan

i got to play with a 4xLuxIII R/O Mag mod tonight and that thing was INSANE!!!! i loved it.

Shane