SMD Tri-Power Mag 2D

Here is another way to use the SMD converter. It doesn't always have to be built into an AA flashlight.



That's three of them mounted on the back of a Mag D heatsink.



One other added component was a 100uf input capacitor where the three converters are wired together.

While I didn't bench this for output current, it is using an SY0J and hits 7120 lux at one meter. A sister 3C direct drive light with a SY0J in it pulls 1.15 amps with new batteries and hits 7080 lux. So, this set up seems to be delivering about the same current level based on brightness.



The thick fins on the heatsink keep it square in the battery tube and allow it to be easily pulled back out with pliers if need be. This wasn't a hard mod, but I would like the whole heatsink and converter to be removable at least until it's done testing.

This one is on the light meter with D cells right now. If there is any interest, I can post the run time plot when ever it gets done.

For guilt free fun, there is also the 6AA to 2D battery holder modded to run the three sets of cells in parallel for 3V output, but with nearly 6AH of power.



NiMh AA cells also recharge fast, so it makes a nice way to run this light without financial pain or having to pitch D cells all the time. But D cells work great, and will sit on the shelf until needed.

lambda,
How many D cells do you need to drive the three SMDs in parallel? How long do you expect the D's can regulate? And yes, I'd like to see the run time plot. I saw barlog's post a couple days ago where he claimed his DownBoy 1300 exceeded 10K lux with some reasonable run time. Doesn't 3xSMD+ put out more amp to the LuxIII then the DB1300? If so, shouldn't the 3 SMD's be brighter than the 1 DB? Please help me understand.
Also, is that heatsink for sell from anywhere?

thx,
ernest

vacuum3d - This uses just 2 D cells. Don't get too wrapped up in lux levels when comparing current levels, as what you are comparing is a T BIN Luxeon to this S BIN luxeon. So even at the same current, the other Luxeon is going to be brighter than this one.

Dropping a voltage higher than the Luxeon vfd is a different task, and down converters are always more efficient than boost circuits. So, it's really a kind of apples and oranges comparison.

This is a simple boost circuit running wide open. I suppose if you want it to regulate, you could limit the output current and get a flat output but at a lower light level. But what's the fun in that?

I lost the chart; operator error, my bad. /ubbthreads/images/graemlins/mad.gif So I'll have to make another. It started the test at 7100 Lux and five hours later when I went to bed it was still producing 4300 Lux. The chart showed the output dropped off to moon mode at about 10 hours. And the 'moon mode' was just over 1000 lux, so still plenty of light this morning when I checked on it, and then exited the program without saving my work. /ubbthreads/images/graemlins/mad.gif Also, max temperature reached was 98F at just over one hour of operation.

I think hitting 10K Lux using a BIN T 3W Luxeon is possible with this circuit, and I'll probably make myself one of these with a BIN T eventually. This particular light is just for testing, so no risking a nice BIN T if things go south.

But all things being equall, Luxeon variations account for far more than driver circuits. If you want the absolute brightest light, get a top performing BIN T Luxeon with a low vfd. It will produce more light with less power. Then it's up to you to decide what battery configuration works for you.

This mod uses $15.00 in converter parts to drive a 3W Luxeon from 2 D cells. Not an elegant design, but very robust and hardy. My best guess is this circuit starts at about ~1.2 amps to the Luxeon and two hours later has dropped off to ~900ma, and at five hours is producing ~700ma. While D cells are huge in capacity, their internal resistance is actually higher than AA cells. So, they don't maintain their voltage well, and as they drop in cell voltage, so does the output of this circuit.

For this circuit to regulate (limit current), the batteries would need enough power to drive the output to a minimum 1.5 Amps. That would of course require three cells. /ubbthreads/images/graemlins/evilgrin07.gif

But before we stick three C cells in there, let me plot the run time for these 6 AA cells. I promise not to delete the chart this time. /ubbthreads/images/graemlins/icon23.gif

UPDATE - OK, here's the run time for the 6AA cells:



The D cells are testing again, but that won't be done until much later today......

Got it. Thank you for the info.

ernest