As requested, 3 XM-L Driver/Emitter module DIY

Piesoup · 2012-10-15T16:50:22.000Z

Ooo, bugger!!

PilotPTK · 2012-10-15T17:37:59.000Z

It’s really not nearly as exciting as everyone is guessing. It’s a fully programmable driver (no led on board – just a driver) that can use the same mode-designer as the 3XML module. It works from 5V to 25V input voltage and will drive up to (programmable) 4 Amps. It can drive any type of LED, and will happily drive any number in series as long as input volts are greater than the series VF voltage of the LEDs. Switch Mode – not linear, so it doesn’t get less efficient as input voltage increases and it maintains constant brightness/current accross the battery discharge. It also has a temperature monitor built in that you attach to the LED star/heat-sink and it will then handle (programmable) thermal limiting. Low battery indication/cut-off (also programmable). like the 3XML, it does support either Standard Mode change style (tailcap Lclicky) with or without memory, or it can support a momentary contact switch with advanced mode settings like hidden modes.

mattthemuppet · 2012-10-15T21:42:11.000Z

my interest is piqued! What’s the voltage overhead? Could it run 2 XM-L in series off 2 18650s @3A without going out of regulation until the very end of the discharge curve, especially if the new “don’t sag as much” NCR18650Bs are used? Any idea yet of rough cost? I’m hoping <$30

I’m thrashing out the ideas for a new helmet light and I was going to use a Taskled Lflex (linear) so I could reduce the battery to 2 cells (less weight on my helmet). This might be an interesting alternative.

antonkochubey · 2012-10-15T21:52:12.000Z

mattthemuppet:

my interest is piqued! What’s the voltage overhead? Could it run 2 XM-L in series off 2 18650s @3A without going out of regulation until the very end of the discharge curve, especially if the new “don’t sag as much” NCR18650Bs are used? Any idea yet of rough cost? I’m hoping <$30

Erm, NCR18650B’s aren’t “don’t sag as much”, 4.35V LG’s are

PilotPTK · 2012-10-15T23:01:21.000Z

mattthemuppet:

my interest is piqued! What’s the voltage overhead? Could it run 2 XM-L in series off 2 18650s @3A without going out of regulation until the very end of the discharge curve, especially if the new “don’t sag as much” NCR18650Bs are used? Any idea yet of rough cost? I’m hoping <$30

I’m thrashing out the ideas for a new helmet light and I was going to use a Taskled Lflex (linear) so I could reduce the battery to 2 cells (less weight on my helmet). This might be an interesting alternative.

Voltage overhead should be less than 0.5 Volts, so yes, You should be able to get away with 2 XML in series with 2 Cells. Your hope on cost will most likely be satisfied.

PPtk

mattthemuppet · 2012-10-16T13:47:34.000Z

Shadowww:

Erm, NCR18650B’s aren’t “don’t sag as much”, 4.35V LG’s are

interesting, thanks! I hadn’t heard much about the LGs, I’ll have to look into them some more

mattthemuppet · 2012-10-16T13:50:05.000Z

PilotPTK:

Voltage overhead should be less than 0.5 Volts, so yes, You should be able to get away with 2 XML in series with 2 Cells. Your hope on cost will most likely be satisfied.

PPtk

that’s great news, thanks! Good job on the low overhead, it really opens up the possibilities. Do you have target dimensions yet or will that wait until component layout etc?

Only downside is that I now have to go back and read this whole thread to see if any of my other questions have been answered (memory of a fish)

scaru · 2012-10-16T14:01:33.000Z

17mm diameter.

PilotPTK · 2012-10-16T14:46:12.000Z

mattthemuppet:

that’s great news, thanks! Good job on the low overhead, it really opens up the possibilities. Do you have target dimensions yet or will that wait until component layout etc?

Only downside is that I now have to go back and read this whole thread to see if any of my other questions have been answered (memory of a fish)

I tried my best to keep overhead low. It’s difficult when you include full reverse battery protection, but I think I chose my parts well. I could take out the reverse battery protection and reduce that overhead further, but I think it’s a worthwhile thing to have…

Dimensions are set in stone, component placement and routing are done, boards are being fabricated. It’s 16.8MM in diameter - fits a P60 drop-in perfectly.

PPtk

mattthemuppet · 2012-10-16T14:59:03.000Z

[quote=PilotPTK]

mattthemuppet:

I tried my best to keep overhead low. It’s difficult when you include full reverse battery protection, but I think I chose my parts well. I could take out the reverse battery protection and reduce that overhead further, but I think it’s a worthwhile thing to have…

Dimensions are set in stone, component placement and routing are done, boards are being fabricated. It’s 16.8MM in diameter - fits a P60 drop-in perfectly.

PPtk

see, I told you I’d miss stuff

I agree, for the target market (drop-ins) reverse battery protection is well worth the trade off. Less so for bike lights but then there’s no point incurring the extra costs of having 2 versions, if the non-protected one is even viable.

The small size will give me some more space to work in and freedom to remove some more material from the housing too.

Shadowww:

Erm, NCR18650B’s aren’t “don’t sag as much”, 4.35V LG’s are

I checked out those cells at the current draws I’m likely to use (~2A per cell) and voltage I can charge them too (4.2V) and they pretty much cross over at the point where PilotPTK’s driver would go out of regulation (~3.45V per cell), with perhaps a small edge of ~100mAh to the LGs. The main difference is that the LGs fall off a cliff after that and the NCR18650Bs have another ~10% of capacity left, which would be enough to get me out of the woods.

The flat discharge of the LGs also counter-intuitively makes it harder to set meaningful voltage warnings as there’s so little slope to work with.

Piesoup · 2012-10-17T06:04:06.000Z

Well done!!

This driver looks awesome, cant wait to get my hands on one.

Is the temp sensor remote, or integrated into one of the ICs? Already thinking up a housing!

PilotPTK · 2012-10-17T06:21:24.000Z

Remote. Similar to this:

The temp sensor is the black bead at the end of the blue wires.

MosesM · 2012-10-17T07:41:53.000Z

I’m considering a new build using a Cree MT-G2 6v emitter (vF = ~6.2v @ 3000mA), do you think your new driver would work well with it being driven by two Li-Ion batteries in series?

PilotPTK · 2012-10-17T07:45:41.000Z

MosesM:

I’m considering a new build using a Cree MT-G2 6v emitter (vF = ~6.2v @ 3000mA), do you think your new driver would work well with it being driven by two Li-Ion batteries in series?

Yep, sure would. Work great, in fact. I’m planning a similar build myself, in fact. I might use 3 cells though just for longer run-time…

MosesM · 2012-10-17T08:00:50.000Z

Awesome! Get ’er done then! :bigsmile:

PilotPTK · 2012-10-17T08:10:08.000Z

MosesM:

Awesome! Get ’er done then! :bigsmile:

I know… Hurry Hurry

Circuit boards are being fabricated. Have to finish firmware. Build. Debug.

Couple weeks…

NightCrawl · 2012-10-17T08:46:31.000Z

PilotPTK:

MosesM:

I’m considering a new build using a Cree MT-G2 6v emitter (vF = ~6.2v @ 3000mA), do you think your new driver would work well with it being driven by two Li-Ion batteries in series?

Yep, sure would. Work great, in fact. I’m planning a similar build myself, in fact. I might use 3 cells though just for longer run-time…

Is there anything special about that emitter?

PilotPTK · 2012-10-17T08:49:08.000Z

NightCrawl:

PilotPTK:

MosesM:

I’m considering a new build using a Cree MT-G2 6v emitter (vF = ~6.2v @ 3000mA), do you think your new driver would work well with it being driven by two Li-Ion batteries in series?

Yep, sure would. Work great, in fact. I’m planning a similar build myself, in fact. I might use 3 cells though just for longer run-time…

Is there anything special about that emitter?

It’s new, it’s sexy, it’s cool, and it’s almost twice as luminous as an XM-L. I don’t suspect it’s going to be much of a thrower though, it’s a bit huge…

Piesoup · 2012-10-17T16:15:26.000Z

PilotPTK:

Remote. Similar to this: !{width:80%}http://www.brightlightmodules.com/Images/SpringSide.jpg!:http://www.brightlightmodules.com/Images/SpringSide.jpg The temp sensor is the black bead at the end of the blue wires.

Fantastic! That will open up more design options. Do any of the ICs need to be heat sinked? I know from previous drivers I've used that the switcher needs to be cooled.

PilotPTK · 2012-10-17T16:18:23.000Z

They shouldn’t. I chose a REALLY low RDSon mostfet switch. It shouldn’t need heat-sinking. Never know for sure till you try it though - that the “Debug” phase

The design goal was for no necessary heatsinking though.

PPtk