How Many LEDs Can I Run In A two-D Cell Mag?

I have a trusty 2-D cell mag with the stock bulb and reflector. Thought I'd mod it over to LED, make it as bright as I can manage. I think a basic limit is how much heat I can disperse away from the LEDs while they're running. Anyone have any opinions on how many LUX one's or three's I can run without overheating them? Any suggestions for who sells a kit with suitable heat sink and snazzy reflector? I wanna' see what this baby can do...

I useually build my own stuff, so someone else will have to chime in as to what board to use. For a 2D size, without getting a fancy 2D to 8AA adaptor, a booster is NEEDED. IIRC a BB750 or a NexGen should work. Try and get a 'U' bin LUX III, and get an O-sink and a UCL. A setup like this is easy, semi cheap, focusable, regulated, and not battery hungry. I have a 2D m@g that takes one of the 8AA to 2D converters, and I am constantally paranoid of killing some of my rechargables due to uneven discharging.

Jeff

WildRice's suggestion is correct. A sandwhich with a single Lux III LED attached to a hotlips heatsink would work wonderfully. If you're really power hungry, maybe three sandwiches each attached to a Lux III LED with its own reflector on an appropriate heatsink will work even better.

3 NiMH C cells in the 2D direct driving a 'K' binned LED can work also.

read here for ideas.

Ken,

If you're up for the mod, you could use six AA's (or even 8 if they are thin enough). With a nice, high voltage source like this you can run three or possibly four Lux3 or maybe even a pair of LuxV with the right heatsink. The Sandwich Shoppe is a good place to look for heatsinks and drivers. You can also get a little fancy and try either a FatMan driver to run three Lux3 from 6AA or use the full 8AA and an nFlex driver to run up to three Lux3 or a single LuxV.

I built myself a 2D Mag w/ HotLips, LuxV, 8AA adapter and nFlex driver and it has turned out to be a very handy light. On it's lower settings it will last many, many hourse before the batteries are depleted and on it's highest setting it will throw a very nice beam with the stock reflector.

Jon

I've never really been interested in the multi LUX mods myself but right now, in addition to a few 'regular' 3C and 3D direct drive Lux III mods, I own a 2D running on 3 C cells with a TV1L (I'm almost sure) and my very favorite Lux-modded Mag, a UX1L in a 2C host running a Wiz2 board at 937ma. It runs on 2 parallel-wired 18650 LiON cells and has a UCL. With the board, it's regulated and I swear it's brighter than either of my direct TV1L lights.

Very cool light.

Next project for even more throw is dropping a Lux III star of some sort into one of the newer style Dorcy 3D Super 1 Watt lights. The reflector is deeper nad I think wider and it definately throws further than a Mag head.

Guys, good solid replies, thanks! I just wrote to Wayne at Electrolumens to see if he'll sell me the parts I would need to make a Quadstar out of my light. Turns out he has Mags running with as many as SIX three watt Luxeons. Must be a pretty good hand warmer once it gets going (G)

My intuition says that I'd get more runtime out of two D cells and some up converters rather than using six or eight little AA batteries in a sleeve. With the D cells I simply have a greater volume of battery in there, with the AA's I'm carrying around more air. Any opinions on this?

(EDIT: Wayne says sorry, no Quadstar kits)

I have a 2D mag, ran with 3 C Alkaline cells and a PTS using 2 T bin Lux3's. That is my most usefully light, and my favorite. I ran it DD, and got 2.4A total draw IIRC.

Ken, good question with respect to power density of the 2D vs 8AA. Of course, the answer is "it depends".

If all you're doing is running a single Lux1 at spec, there's absolutely no reason to use AA's. If you're serious about running 4 Lux at or above spec, then you could make a case for 8 AA's. This would make a great expirement actually.

I haven't tested any of this, so I may be a bit off, but here's my take...

Figure that 2 "D" cells will need to provide at least 4 amps to drive four Lux3 at spec (12 watts total). That same 12 watt requirement can be meet with 8 AA's and only a 1 amp drain. How long will a pair of 10,000mAH NiMH "D" cells run at a 4+ amp drain? How about the 2,500mAH AAs at a 1+ amp drain? How efficient will the boost circuit(s) be in the 2D scenario? You'll need at least two, most likely four. In the 8AA scenario you'll need one buck circuit, two at the most, and they tend to be more efficient than boost circuits.

Maybe someone out there has some real life data they can share?

As VTWim mentioned, you could always go the 3C route and direct-drive two or three Lux3. It would be very bright (although it's unregulated and you'd burn through alkaline "C" cells). You could also try to direct drive two or three "J" or even better "H" binned Lux 3's using 3 C NiMH.

Jon

If you want to run on 2 alkaline D cells as in the original Mag, then you should realistically limit the setup to something like a Badboy 400 driving a Luxeon I. As others have already said, you have a lot more options if you use that 2D body to cram in other, more powerful, battery configurations. But the original two D cells are hard to beat when it comes to total energy capacity, and you can make a Luxeon run for a long time that way so long as you're not trying to pull a very high current from the batteries.

I'm using three D cells to drive a Luxeon III near spec using a Wizard2 converter. Two alkaline D cells would not have been adequate for the power demand of this arrangement. My next Luxeon mod will probably use three 123A cells in a 2C Mag host, with a Downboy 1000 delivering current to a Luxeon III.

OK, how about this setup?

Great Info folks!.

If I convert the 2-D Mag to use 3-C cells I would have 4.5 starting volts.

The Quickar people have three watt/55 lumen white star LEDs for $12 each.

http://cgi.ebay.com/NEW-3-WATT-WHIT...ryZ66952QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

The stars are meant to run at 4.0 ~ 4.2 VDC and use 700 milliamps. They'll light down to 3.8 volts according to their spec sheet. Their color temp is 6000k, which I think is cool white.

Lets say I get four of these stars, wire them in parallel. I would need either a resistor or a mmm, 3mm LED to cover that .3 volt overage I would get with new batteries.

If I set up four of these LEDs on a heat sink, would three C-cells be able to produce 12 watts to drive them? Would a heat sink that is small enough to fit into the head of a D-cell Mag be big enough to cool them?

Is it possible to calculate what the runtime would be? How would I do that?