LZZ-06 mod#2: XM-L2 T6 3C, BLF-tiny12 driver+FET, Efest 10440 V2 ***27 lumen/gram !!***

I did the test-run with the clear possibility in mind that something would blow. But nothing did, it just went skin-burning hot (I hurt my fingers switching it off, as you may hear in the video). Now that I know that it can handle this abuse, I will not be using the flashlight on high for that long anymore. These type of lights have a very effective thermal step-down: if it is too hot to hold, then switch to lower mode ;-) .

Nice! It is incredible that we have 650+ lumen flashlights the size of out thumbs these days.

Way to make it happen!

BTW. Maybe I have found a good FET to use for these small style lights.

Search the net for:

CXDM4060N

The highlights are :

Continuous Drain Current (Steady State) ID 6.0 A

rDS(ON) VGS=4.5V, ID=5.0A 30 mOhm

Qg(tot) VDS=20V, VGS=10V, ID=6.0A 12 nC

Qgs VDS=20V, VGS=10V, ID=6.0A 2.0 nC

Qgd VDS=20V, VGS=10V, ID=6.0A 2.2 nC

In a SOT89 package (same as AMC7135)

nice!

unfortunately i dont understand completely how these FETs work…

has anyone a source of wisdom for a noob?

Hey, that would be far too easy, fits straight on the tiny boards.

I think comfy has shown the leads are backwards, and by looking at the rDs 30 mOhm, comfy’s run about 4.5 or something like that

The Rds isn’t a fixed number. It’s a bit like Vf for LEDs but is voltage dependent instead of current dependent. You have to look at the plot of Rds on vs gate voltage. Most FETs aren’t fully on below 4.5v so you also have to look for one with a low gate threshold. Max current ratings and Rds on are given at the ideal voltage, sometimes 10V.

Bty Djozz. When I ordered a bunch of cells from Efest they recommended that the label be removed before use.

Djozz, cool build! Now you've got me thinking about tearing apart my Tank007 E09... I really should just leave good enough alone ya know, it is pretty good as is for an EDC but the tinkerer in me sometimes overcomes my rational side.

led4smoke, as Warhawk-AVG pointed out, the resistance levels on that MOSFET are really high...orders of magnitude higher than the 70N02.

Djozz, awesome work! That is one tiny powerful light!

Does your 105C have low voltage shut off??

Djozz wrote:

A picture with my thumb to get some perspective how small it all is:

Wow, that is a small thumb. Sorry it's all in proportion.

Excellent build and write up. Absolutely love that light.

Please excuse this dumb question. Does that SMD Capacitor have a polarity or were you just marking positive because it's hard to tell given how close both ends are to the ground ring?

Wow! incredible mod.

Are those tiny 10mm and 12mm driver boards still available?

Ceramic capacitors aren't polarized.

RMM: thanks! I know you are a professional modder, but for others who want to mod tiny lights some of my beliefs: apart from the driver, the key to succes I believe is pay attention to every electrical connection (I used this particular light in these mods because of the lack of switch, and because it seems to have a low resistance spring), and taking very good care of the mounting of the led board: both the board and the surface must be really flat (shiny is not necessary, flat is way more important than a highly polished finish, but there will always be believers...), with very little Arctic Silver in between. Also I suspect that sometimes too little solder is used for the thermal pad of the led, making the contact surface less than optimal.

RaceR: thanks also, as far as I know and in my own experience, the 105C has low voltage warning and subsequent shut-down.

djozz, I wouldn't consider myself a professional, I'm just a hobbyist who builds a few lights for others on the side. There are many on this board who are far more proficient an electronics, soldering, and many of the other elements that go into making these lights. I have a BS in Biology and understand basic electronics, physics, chemistry, etc., but nowhere near enough to consider myself a professional in any of these fields.

The one or two 105Cs I tested a long time ago did not have shut down (warning, yes). They could drain batteries below 2,5V.. Might be differences in firmware on the 105C for all I know...

That sounds familiar, I am a biologist too, (but with interests in almost everything that comes on my way, exept perhaps women's shoes).

I will probably find out about this one, going to do a runtime test on medium and low.

I did an output/runtime test on medium and low, I edited the OP.

RaceR, you are correct on at least the NANJG105C I used here (from Fasttech), and I guess then on all 105C's around: it has low voltage warning but no shut-down. For big batteries it is no problem: the low voltage flashing is done with a low low output that even below 3V will not easily kill your battery, but for a 10440 it does matter a lot: it goes from 2.93V to below 2V in just 10 minutes, as I just found out (but in the end the voltage will be lower than the minimum led Vf).

Rds is a moving target, it goes up with increasing current and down with increasing voltage so at 2 A it might not be far from the 70N02 at 7A but we won’t know until testing. The listing I saw showed 18mOhms at 4.5V and 20A draw for the big FET. The gate pin matches up but the drain is in the middle and source is on the left and big tab so it’s close but not quite.

The 10.5 mm and 12 mm boards are available from Oshpark and are 1.6 mm thick. I still have some of the 10.5 mm boards that are .8 mm thick.

Last weekend we made a flashaholic party
with some nice guys and many intresting flashlights .

I got this light from Jos
and I love it.

Small and incredible bright.
This light has a real WoW factor !

Thanks