Direct Drive MT-G2 with Two Samsung 20R's

Thanks for the info. I was going to PM you ask how well your light coped with the heat.
If all the copper you used want get it done, then what will?

Active Cooling, not passive. If one would forgo having a waterproof light, then a larger body light, (3x18560 or 4x18650), with a large head could be used and add a cooling fan.

Original led shelf

Copper CPU heat sink underneath

Cooling fan under the fins if the heat sink

Metal separation plate, so there would be inlet air and outlet air

Holes drilled in the head at both inlet and outlet.

With a 2S/2P battery set-up, you could just use a 6v fan. Plenty of them in round format, to fit into a head

Best off with a head/body made by someone with a lathe

I was going to do similar with an all copper light and 7xSST-90 leds, but I could never afford to make it.

fan

It could be simplified by drilling holes in the original led plate and letting the fan blow thru it and up around the reflector and exhaust out holes near the bezel area. For a custom one off light, who cares about the holes really?

Or, everything could be made so the fan area is sealed off so moisture only gets there and use a sealed fan.

I put together a direct drive last night with 2 king kong ICR’s to a MT-G2 It’s in a body from a 4xt6 no pill so the heat transfers directly to the head and out of the light. Works great outside but it’s well below freezing outside right now. Orange peel reflector 3,000 lumens, excellent flood and the tint is super. Perfect for walking around the backyard with (five acres) but I wouldn’t take it on long hikes. It was still at 3,000 lumens when I came inside. The head was hot but not the batteries so that’s good.

I put two of the Samsung 20r’s in a ZY-T08 MT-G2 that has a lustefire driver, it was popping the protection on Panasonic protected batteries after 30 seconds or so on high. With the Sansungs it was way more lumens at startup but dropped down so fast that it wasn’t worth running them. So I’m running Sanyo unprotected and it’s great.

I like to test em on rested cells. My SoShine S1 Max V3 charges these to 4.21V, after a rest period they stabilize at 4.18V. This was just done recently, as I haven’t had my lightbox long, and the weather has been chilly so the cells were probably under 70ºF when I started the test.

I also took the body off the M8 and tested it with 2 Powerizer 26650 cells. The amperage was almost identical to the 20R’s with slightly more lumens at start-up, but falling the same. The 20R’s seem to be a near equal to the larger 26650 and it’s one of the best out there.

I tested 4 different cells with the MT-G2 in the M8 in it’s regulated form, with interesting results…
Sanyo lap pulls 5.92A 2205 OTF at 30 sec.
Efest IMR V2 5.96A 2260 OTF at 30 sec.
Sam 20R 5.98A 2087 OTF at 30 sec.
Pan PF 5.98A 2322 OTF at 30 sec.

The Panasonic does what the best Hi Discharge cells do but have considerably better sag control with their 2900mAh capacity. So that’s what stay’s in em. The Sanyo lap pulls at 1.08 ea. hold their own quite well too, best bargain cell I ever bought! (HP battery pack, 12 of em for 12.96 shipped)


Sliced and diced

OL, that ought to do it. :bigsmile:
That’s probably a little more time than I would want to invest at the moment, but who knows if I cant find some happy medium. Where have all you MT-G2 users been hiding?
I might end up making a copper aluminum head extension, similar to what OL was suggest with the 4D. Just use the 2D and a massive extension.
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DBCstm, did the tint shift noticeable after your dome fell off? :bigsmile:

I too would be very interested in that test. Perhaps even a SBT-90. With almost half the Vf of the MT-G2, the watts and heat would be almost half at 9-10A. If lumens are close to each other, the SST-90/SBT-90 might be a better bet. Is there sinkpads/noctigons available for SST-90's?

The MT-G2 should definitely win in the lumens department, but potentially higher lux and cleaner/tighter hotspot from the single die sst90 could be beneficial in some lights. A comparison between a 5000k sst/sbt90 vs a 5000k mt-g2 (domed and trimmed) would be very interesting!

The dome is still on 007, it’s just been sliced off directly above the die surface, and the phosphor extensions around the dies diced and removed. This gives a bit tighter hot spot, a little warmer tint, and better throw from the hybrid reflector in the Solarforce M8.

All in all, a nice experiment. Tint is about the same, maybe a bit more towards green than pink, as my triple Nichia 219. It looks merely warm by itself, but side by side next to the Nichia, it’s not as rosy a warm.

The M8 has a separate pill from the rest of the light…the pill is the mid-section that the battery tube and head screw onto, with the Noctigon thermally pasted directly to a shelf on the top end. I’ve added 1/2” of copper under this shelf, which of course is still not enough.

My plan is to put any money I receive at Christmas towards a fully copper mid section. VOB will be doing this for me. A bit wider in diameter, with thinner fins than the stock finned mid-section and about 10mm longer as well. The Noctigon will then reflow directly to this finned copper mid-section and it should be good for me to go direct drive. I will be utilizing a 20A switch…the smart switch, from mattaus in Australia. Should be good for the full 12A and we’ll see how the Panasonics handle that.

Might be pertinent to have VOB machine the copper section to fit his new HD2010 extension tubes and go with 2 26650’s instead of the 18650’s for better sag protection and longer run times. Hmmmmm……

The sliced and diced emitter in the baked M8 pill…

“Pill” in the M8, notice that the HA TypeIII anodize baked into an olive green military look, which compliments their choice of font quite well!

The M8 baked, in shorty configuration using one tube

Hi Dale. I thought the sliced and trimmed MT-G2 had a cooler tint than the original unmodified MT-G2? How does the tint of the sliced and trimmed MT-G2 compare against a dedomed XML2?

That is pure flashlight porn there! (running off to bathroom) 8)

here is a copper sink that i was going to use in a monster build but never got a chance yet to start lol but that’s what u need :slight_smile:

!!

holes drilled for the wires and drilled and tapped to hold your star in place. with a set screw to hold the slug in place in side a maglite body
!!

Ive been doing direct drive MT-G2 for some time.

With fresh 20R, im seeing around 9A on startup and uptowards/around 9,5A after a bit (15-20 sec?) runtime (on the tail).

Thread and post here.

If you want sustained high output, the Sony 2600mAh 26650 is better than the 20Rs.

Ill start a beamshot thread some day this week comparing that light and several other high output lights, already have the pictures. :)

Like a big fuel tank for heat, huh Nitro? :wink:


Race, the Powerizer 3600mAh cell does even better for total amperage, just saw today that while the 26700 Moli doesn’t make as high amperage at start-up, it holds it longer than the Powerizer. A trade-off. Kind of tight squeezing those Sony’s into places made for 20R’s……

Proper direct drive MT-G2 makes a lot of heat.. Larger 26650 lights are better suited, and 26650 are generally better at maintaining high voltage under load (not that my 26650 light has got a pill to body contact that is well suited for direct drive 26650, but it works. :)

I have yet to see some discharge graphs for the Powerizer compared to the Sony cells. If you want better amperage, King kong is an option too. :p

Question is, is the Powerizer on level with the Sony in terms of voltage sag when its been used for some time.. Direct drive is all about limiting voltage sag and achiving high amps.. J) (atleast for me it is)

A comparison picture I posted in another thread, but 10A is kinda similar when looking at the cells ability to maintain high voltage.

Peak amps on the 20R and the US26650VT are quite similar, but use them for 5-10 minutes and its easy to see which is better.

I hope HKJ will test the Powerizer and more 26650 cells. Im in need of more 26650 cells..

I had figured that out by your description, I was just poking at you a little. :smiley:
Thanks for the info about the tint. That M8 looks awesome as a MT-G2 host.
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I stuck everything together late last night. With 2 Sanyo UR18650FM protected batteries I was seeing 4.5 amps of tail cap current. With the 20R’s I was seeing a little over 6 amps in the mag with everything stock besides the heat sink and the led. The cells where a little down on voltage as I had been playing around with them without charging them up.
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It lit up a power pole at a hundred yards like daylight, huge hotspot and that’s with a rebel reflector. The XML in a mag does good at lighting up the power pole too, but it doesn’t light up the whole pole with intensity like the MT-G2 did. It lights up everything in the beam path even the spill is bright.
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The mag did not seem to get that hot until after about a minute. I had used some thermal paste in between the head and tube threads but most all the heat was running down the tube. I had finned the head to help get rid of some of the heat, but after a minute it didn’t seem like the head was absorbing much of it. I guess it was making heat so fast it hadn’t had time to get to the head yet. The tube heat was increasing with every second and I could definitely tell where the heat sink was placed. Didn’t run the light much longer than that. I was impressed with the amount of light this mag was putting out. I have a 4 XML kung running 10 amps and doesn’t seem as bright from memory as the MT-G2 mag. Maybe I’ll find time tonight to get them outside and compare.

Very nice, love it when a plan comes together! Are you as impressed as I am with the Sanyo UR18650FM cell? Who would have thought a $1.08 cell would perform like that! :slight_smile: But then, they didn’t cost that new going into the HP battery pack I’m betting.

I’m really loving the MT-G2, incorporating it more and more. Wish it weren’t so hungry, but I reckon it’s the nature of the beast. Thinking about using one in a smaller light, keeping power level down and accepting the lumens it makes for the gorgeous tint I prefer.

My Shadow tc300 (a modest size light) modded direct drive with a MT-G2 does 8 amps (initially) on two cgr18500ch's for a few minutes of wow, and for prolonged use I can put two A123 18650 LiFePo 's in it for 2A and 1100 otf lumens.

How is the heat in that one djozz? Is there a line there somewhere in the middle where the choice between XM-L/XM-L2 crosses what the MT-G2 is doing? I put an XM-L U3 in a SupFire F9, driving it at 4.41A with Sanyo lap pulls for 1259 lumens OTF at 30 sec.

Makes me wonder at what point the 2 footprints cross over in lumens, amps and heat. Where’s the happy medium?

I’ve also got an XP-G2 in my Convoy C8 pulling 4.55A on a Samsung 20R and making 883 lumens OTF. Tighter beam yet again over the XM-L footprint.

It’d be cool to find out where the heat was the same for the 3 sizes, at what amps and then what the output was by comparison. If heat were the determining factor, say 125ºF at 5 minutes on the plane of the emitter on the head. Wonder how that would end up? Might be a surprise to a lot of us!

EDIT: I might just try that. Convoy C8’s in a host only are about $10. So 3 of those would be about the cost of a semi-normal light. With an XP-G2, XM-L2 and MT-G2 I wonder what the magic amp number would be to create 125ºF at a given place on the head in 5 minutes? It’d be an easy thing then to compare beam profiles and lumen output, as well as kcd and throw range. Hmmmmmm……

Direct drive seems to be a common way to drive the MT-G2, if you want some serious output. Has anyone else used a buck driver with 3 or 4 cells besides MRsDNF to regulate current? I’am not really crazy about the idea of running 3 or 4 cells in series, pushing 6 amps or more through each cell. One lazy cell could spell disaster with that much current. Looking for ideas before I go and spend several hours machining a solution. 2 cells and a voltage modified amc7135 driver with modes seems might be my best option, but I wouldn’t mind running the MT-G2 at 8 or 9 amps fully regulated either.

007, it seems like 7A is the best middle ground. For the amperage required, the heat produced (and dealt with) and output…the heat produced and likewise expense gone to in order to deal with it is really more than the output is worth after 7.

And, well, it does seem like 7 is your “lucky number” :wink: