DC/DC Converter for 15 Nichias? (BB500?)

I've got a 2C mag that I'd really like to turn into a nice little LED-based flood light. But with only 3 volts from the two C cells, I don't think there's enough voltage.

So, I'm thinking that something like a BadBoy 500 (sans LS) might be able to generate the voltage & current necessary for this many 5mm Nichias, AND it will be regulated.

Based on what little I know about electronics and what I've read in other posts here, it seems that if the 500ma BB drives 15 LEDs in series each LED should get about 33ma per LED. I have a feeling I'm wrong and it's not that simple (voltage drops across the LEDs maybe?). Can anyone comment on whether or not this would work?

Thanks

Jon

Parallel em nicely... try and get 15 LEDs with around the same forward voltage.

Parallel... Excellent, thanks Nerd. I was wondering about that - I read somewhere about parallel vs series resistors and must have gotten confused.

I just took another look at Wayne's Sandwich Shop... Now I'm thinking the BB700 board should drive 21 of them at around 33ma. Will heat sinking be a consideration at 33ma and/or this many LED's?

Jon (who's getting really excited about his first real mod)

quick question, why go with the nichia's??? 1 luxeon is brigter than 15 of them?

Plus you have far more optics options with a Luxeon than with a bunch of Nichias. It's hard to collimate 15 sources well, collimating one source is much easier.

Well, my requirements are a regulated flood or semi-flood that fits neatly into a Mag 2C. Ideally I'd like a regulated DIY version of an M3/KL2 combo.

I've got a BB500 in a mini-mag and as far as a flood light at close distances (5 - 10 feet), my Inova X5T is every bit as bright and useful with it's 5 LEDs. Along those lines 15 LED's should produce a brighter flood.

I may go with Wayne's 700ma board and pop it up to 21 or 22 Nichias.

But, you're right, another option is the BB700 board with two LS's at 350ma, but then I've got to figure out how to secure the optics inside the Mag's head (don't want to just jam them againt the lens). Is it possible to epoxy them to the LS's?

I'm open to using one or more LS's if the quality will be equal and I can find a decent way to secure the optics - it's just that I've been kind of set on a putting a big honkin array of Nichias in the 2C Mag.

hmm... Could the BB700 drive a 5w LS with just two C cells?

Jon

The BB700 probably could drive a 5W LS with 2 Cs.

AAs can barely put out enough current for a 5W, and that was with a LOT of experimentation with the converter by lambda (I think it was lambda), but 2 Cs should have more than enough current capability.

BTW, as far as getting a nice flood - Have you tried the McFlood reflector optics?

I have a badboy 500 and a innova X5T, the badboy spanks the X5 for up close work, its got a beam thats a little over 2 times wider and puts out 2-3 times the light. This is with the Mcflood reflector of course, the NX-05 is to tight for upclose work.

OK, I guess I should read up on 5w LS's and their optics... I still don't know how I'm going to get the optics seated in the mag head. With the Nichias I wouldn't really need optics assuming I get 20 degree LED's.

Entropy, no I haven't tried the McFlood. I actually like the NX-05 in my mini-mag, I'm really just wanting an impressive and smooth flood from the 2C.

Rifter, how did you put the 5w optics in the Mag 5D's head?

And yes, the NX-05 on my BB500 puts out an almost painful hot spot up close (I tried to read the part number off of some burnt out automobile bulbs w/ it - big mistake!).

You should try the mcflood, its really great for flood lights. I didnt build the 5W light wayne from elektrolumens did, his website is www.elektolumens.com and from the looks of it he removed the bottom half of the mag reflector and epoxyed the 5W and optics package to the rear of the mag head assembly.

Excellent... Any idea if the McFlood works for 5w (is that what's in your 5D?)?

my 5D has the collimateor optics(dont ask for model number this is what wayne told me, ask him), which is also great for a flood light as well, the 5D mag really throws out a great flood light with a little hotspot, its great for trailwalking.

Thanks for the help Rifter and Entropy.

Unfortunately I now have even more ideas (and questions) and before I considered the 15
Nichias... Back to the drawing board.

Jon

I've used the "micropuck" from www.ledsupply.com
to drive 12 (so far) Nichia NSPW500BSs in parallel. (I would do more but I have run out :-(
of them... The micropuck is designed to run a Luxeon Star (white, blue, cyan, green) off 3 V.

The Ray o Vac 2D yellow plastic "industrial" flashlites are perfect for this, as they are cheap, and the reflector plastic is easy to cut and trim as needed.

I could do my own step-up circuits, but being basically lazy, I let someone else do the heavy lifting for me ;-)

The micro puck steps up 3V and maxes out at 375 mA which is perfect for a Luxeon Star or a group of 12 to 15 NS{W500BSs.

/ed b

hmmm... So assuming 2C's can put out enough juice to drive two micropucks (any idea?) I'm looking at two sets of 12 Nichias in parallel, or 24 in all. Should drive each LED at just under 30ma and hopefully put the KL2 to shame (even if it lacks the throw of an LS-based light).

I'm still partial to this style of mod mainly because while it will be a bit more tedious, it should be easier to find and work with the Nichias than 1W or 5W LS's.

--Just check their site. Ouch, it'll be $45 for 30 LED's (granted I don't need that many, but...) plus another $30 for two pucks. $22 for a BB700 plus whatever a 5W LS will cost (if white ones can even be found since I didn't get in on the group buy)... My little Nichia mod is going to be expensive. If 2C's can be used to drive the BB700 and a 5watter, that will be the more economical route.

Jon

As to optics: The 5W emitters and 1W emitters are similar enough that the NX05 and McFlood will fit. The NX05s don't get quite as much collimation since the die itself is larger in the 5W units, but they work. McFloods are known to work very well with 5W units. (Look for one of McGizmo's posts about a 5W cyan with a McFlood in a McLux head.)

Entropy,

It's looking like the 5 watt LS mod w/ McFlood will be the way to go (again, if I can verify the BB700 is good on two C cells). Any idea where I can find a white 5w LS?

Jon

For the Nichia and the 1W Luxeon, a 2 cell Badboy 700 configuration will be OK.

For the 5W, there is no 2 cell configuration that will work except two 123 batteries. Vin must be greater than 3.8V or so for the 5W Badboy 700 configuration.

Wayne

dat2zip,

Thanks for answering that; I was wondering the same thing. It seems like a 2D and possibly even a 2C configuration should be able to handle the current requirements if the converter were designed for that much difference in voltage. Would you agree? Is a 5W 2D light realistic with a different convertor or do you really need a higher input voltage?

There has been much discussion about using a 2D flashlight body for 5W mods using 6AA or 8AA with some kind of series/parallel combination driving a Badboy 700. It seems like a 2D configuration with a different convertor would be simpler, cheaper (assume the convertor costs the same), and have higher capacity. Is there an electrical consideration that I'm overlooking, or might pursuing a 2D configuration be a good way to go?

2D bodies generally have more room to work with (lots of wasted space in 2D maglites) so the convertor wouldn't need to be as compact as your Badboy boards, and as I understand it, the size requirements were what made the Badboy tricky to design.

- Russ

Thanks for commenting Wayne, that's exactly what I was afraid of... 123's are pretty expensive, I was hoping I could stay away from them. But, if I need to, I need to.

Any guess (from anyone) what kind of runtime I'd see with three 123's driving a BB700 & 5W LS (assuming the ~9v Vin isn't too much)? I could even do 4 123's split series/parallel after fabricating the right adapter...

Jon