Interesting graph to look at, the you would need to think how much IMR14500 sag

http://budgetlightforum.com/node/22636#comment-417559

The 6V MT-G2 is the one people use with 2x18650 cells. At high current the MT-G2 has a higher voltage than 6V, 2x18650 cells have voltage sag, and usually there is some voltage drop in the flashlight (often the clicky), all this together makes the MT-G2 run fine on two li-ions. In the thread Hikelite links I described a MT-G2 direct drive build with two CGR18650CH IMR cells, with full batteries it runs at 8amps (3000+ lumens ).

(I'm not sure if I bring much news here BigC, you've been around much longer than I )

Since the MT-G2 (on a copper board, when heatsinked) will not blow at any current below 16A, you can experiment with almost every battery configuration that outputs more than 6V

Just make sure you put it on a copper star and you’re good to go.

Bigchelis wrote:

Reminds me of my Surefire L1 Mr. Lamdalights put a solid copper chunk in there with SST-90 soldered directly to the copper boardless. That sucker was a heavy tiny light with 5~6A of current off IMR 18500 and too hot to hold shortly after turn on. bigC

That is the fun with the direct bond to copper (available to a layman like me since the Sinkpad came out ), it almost doesn't matter anymore how small and hot your flashlight is: the led just keeps going.

Bigchelis wrote:

Thanks to you guys here 8) I just purchased the TitaniumInovations 3AA to 1D cell holders. 2 of them to be exact. I got the series variant, so each one will give me 4.2V~4.5V input. Effectively putting me in a perfect spot to overdrive this LED. Now, I have to re-think what 2D cell host can be made into a twistie rather easy....lol Best, bigC

That sounds like it will work very well. Could you please give an update when the mod is done (with pics of course )

Only one way to find out...   (would be easy to say that if the MT-G2 wasn't so expensive!)

The MT-G2 with a good thermal path can take quite a bit of abuse and draw a lot of power!  My guess is that it is going to suck those cells down to a reasonable voltage quickly with the amount of draw it is going to put on them.  It may be safer to try 6D first and see what voltage sag you get when turned on, then you can decide whether or not 7D is a good idea. 

Bigchelis wrote:

Does anybody know for certain if I can even do 7D NiMH on DD ? Thats about 9.8V input when cells are fresh off the charger, but they very quickly get to the stable 1.2V input each. So, would you guys even try 7D cells or stop at the safe 6D cell configuration? Thank you, bigC

I couldnt find the 6D light on autozone.com. Is the heat sink as thick and heavy as the 3D defiant? Im looking forward to your mod pics. I bet this would accommodate 4 × 32650’s.

it should, may be even 5.

i’m thinking that light, mtg2 and b3 flex, or hb flex if mtg2 is 36v. should be very bright.

i recently build mtg2 4c mag, with deep rebel reflector, but i still had to use difuser film, cuz beam was full of artifacts. regular inc. mag reflector did not focus mtg2 at all. b3flex offers temp control, if glued to same heatsink as led.

I found the 6D: http://www.autozone.com/autozone/accessories/Police-Security-Hi-intensit...

Im sure George could set us up with an excellent driver, but then we would quickly run into problems with heat sinking unless a much larger deeply finned one could be made.

Its hard to beat the bang for the buck when considering the super easy Trustfire X7 MTG2 mod. The large stock reflector takes advantage of the MTG2 and casts a fantastic beam. It would have been nice if it came equipped with a 26650 or 32650 battery tube, but it already does well on its own with 3 × 18650’s.

Bigchelis wrote:

Just a quick update.

I went to AutoZone and purchased a $33 dollar 6D Flashlight. Almost identical to the homedopot Defiant 3D in terms of heatsink screwing out and incredibly easy to mod…..

The 6D from Autozone is rated at 200 lumens via an XP-E emitter and its a 20mm star. So, the 20mm star MTG2 would fit like a glove.

The reflector is plastic and the Lens is too. Fortunately my UCL Mag Diffused lens are exactly the same size and it fits perfect.

The stock driver I am not sure what it is. But the XPE pulls .525mA at the tailcap with 8.4V input. So, thats pretty good 4watts~<.

Hopefully, I can finish the project this week and post results.

bigC

I’ve been eyeing that light for MONTHS with that same thought. It would almost be like doing the same mod to a 6D Maglite. But without all the fuss and expense of trying to find an appropriate heatsink. I’m sure that light would be AWESOME with an MT-G2 and six Tenergy Centuras or Premiums. I’m just surprised nobody has done it yet. But I guess most people would prefer to do smaller lights powered by Li-Ion batteries. By the way, do you know what the driver size is in that light?

Speaking of Li-Ion, I wonder how an MT-G2 would do with a couple of A123 Systems LiFePO4? Voltage would be lower than with two IMR or ICR batteries. But with those 70A 26650s, voltage sag would be practically nonexistant – a constant 6.4V throughout the entire discharge. OR, add another for 9.6V.

I think the switch has a lot of resistance. I’ll have to come up with something to replace the stock switch as well as to increase the heatsink mass.

It’s just that it’s so dang big. It’s like carrying a baseball bat around. Maybe that’s why you like it, but, it’s just massive for that 200 lumens.

The holdup on your MT-G2 version is the switch. The stock switch is pretty cheesy and will melt when we turn it on with this emitter.

Rufusbduck wrote:

Just make sure you put it on a copper star and you’re good to go.

Tons of light because you are now holding a small sun! 2000+ lumens from ONE emitter! Whoah!