I don’t know about efficiency but in the same reflector light the MTG is an absolute flood of light compared to a skinny little beam from the XML-2 not that we would of said that six months ago. In throw the XML-2 is in its own league.
I too did wonder this.
My guess on the thermal protection is an integrated temperature sensor in the MCU. Most small MCUs made in the last 8-10 years include one. In most cases not overly accurate, but good enough to protect from overheating.
I guess in some cases, the driver designer went a little cautions on the cutoff temperature.
The LusteFire driver doesn’t appear to have any intentional thermal cutoff, although I figure catastrophic ‘cutoff’ would occur if left on for too long with no cooling. I’m not sure if that driver is available from anywhere on it’s own. Would be interesting if it was, or was requested through a certain popular online store 
Living with the step-down may be your only option until a driver can be sourced. There’s are not many drivers available that can deliver a sustained 50-70W of power.
It’s a shame but I don’t see any good options, so I think I’m just going to pull it back apart. Too bad the 7x driver burnt out it was a thing a beauty while it lasted. What gets me is that although it was bright it still wasn’t as bright as my 6xU3 and it runs fine on the same driver. I wonder if the driver itself had a defect and that’s why it didn’t drop down or possibly something else wrong with it altogether.
Well does anyone need a 9amp driver? I have one to sell you cheap.
Need? No, but... seeing as how I'm the one who talked you into trying it :X , PM me your price and where to send teh munniez. :)
sorry to hear the bad news. at least you attempted it. out of curiousity tho, was the flood and spill on this thing greater than the 15xml you have?
No but it had a nicer tint and better beam profile, zero rings which was nice.
Three h6flex Taskled drivers, Master/Slave, set at 6600mA per led. I'm considering it. I talked to George about it. It's feasible, but it might be too much for the Master at 6600mA each, It should be good at 5000mA each.
Someday when I got $125 to buy drivers, but I bet it would be a kickass light!
There’s got to be a driver to do it, if it didnt get hot then it wasn’t to do with heat, either too much current or a pre-broken driver, and it kinda sounded like a faulty driver to me if it didnt even get as bright as that other light even for a little bit. They should easily do 2k lumens each…
It would take a heck of host but it could be done with that, 5k each would be amazing.
You would think that there must be one someplace, but the problem is that choices are limited due to size as well. I really thought the 7x driver was going to do it. Oh well someone will find a driver one of these days and I’ll revisit this build when they do.
I already pulled it apart and mounted 3 new XM-L2 U2’s on noctigons I didn’t dedome these so it will be floodier kinda like a shocker on roids. It’s getting driven very hard with a low PM driver. It will outflood and outthrow a stock shocker easy.
Got my attention. 15 amps total. Can I borrow it in the winter, like now. 9 amps heated half my house. 5 amps heats the lounge. 
how many lumens you say? and lux? 4200 and 200?
That’s a good guess.
My driver that does the advertised 9 amps on the left, and 18sixfifty's driver on the right which only does 5.6 amps no matter how many cells you throw at it.
Anyone spot the problem? :facepalm:
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One thing I did figure out while running them out in the open, the heat is coming from the FET and/or other stuff on the topside of the upper board, under the choke/inductor/whatever. The part that has zero connection to anything that could keep it cool(ish)...
I honestly don’t have a clue how these things work so you would have to point it out to me. Although from the picture it looks like you stacked resistors or did they do that?
I haven't touched the resistors on either one. There are 3 more pads for more resistors directly opposite those, and both drivers have 3 R200s there. So one has 9 resistors and the other only 6.
Nice to see that these are easily adjustable between 5,6A-9A then depending on the resistors.. :)
Comfychair, would be valuable information if you were able to figure out if less output equals a noticeable change in overheating issues. And if adding some heat sinking will improve it. :)
btw, does this driver have audible PWM, slow mode changing or any other annoying downside beside the overheating issue?
Well WTH? I guess that explains that doesn’t it?
I wonder if MRsDNF's underperforming driver also has only 6 R220s? (edit: R200s, durrr...)
I do hear some squealing but it's from the questionable connections between cells, I've just got them stuck end to end with little magnets that are really too weak for this. I never heard it making noises when it was installed in a proper light (the TR-1200). Mode changes are normal, not like that 3(yeah, right)-18v thing.
The top surfaces of the FET and the two diodes are at the same level so it should be fairly easy to JB Weld a piece of copper plate on there and connect it to somewhere it can dump some of that heat. But I really don't understand what it's doing or trying to do that results in that much waste heat, it gets hot enough after about 45 seconds that it'll sting your fingers pretty damn good. The 6.5A piece doesn't seem to run noticeably less hot than the one doing 9A, you could cook a tiny little egg on either one of them.