From Richard (RMM) -I would really prefer to keep the MT-G2 down around 9A-10A because after that it’s not making a lot more lumens considering the extra heat.
With an MT-G2, your most probable best bet is in the 7A-9A range. It’s really making a LOT of heat up there, for the lumens it’s outputting. So be prepared to have a light that is set up to handle it if you want to run it up towards 9A or higher. As in… I had Bucket make me an 8 ounce copper pill in an Solarforce M8 for a FET driver on the 2 cell set-up. It’s still not enough to run very long, get’s really hot really fast. That’s at around 12A.
For an mtg you need the 6V option. How much current you need is between you, your cells, the light, and a pair of oven mitts. At 1A it will be brighter than most flashlights my parents ever knew of, at 2A it will be a work horse in any decent sized light(C8 or better), above that you will run into compromises between number of cells, size of host you wish to carry, overall run time, time in turbo, etc.
I have to admit though, a triple 9V MT-G2 BTU Shocker is pretty dang sweet! One little 17mm FET driver, 10,000 lumens. A quick favorite of mine to be sure.
Edit: I used the 9V variant on the MT-G2, the Shocker has a 3 cell carrier that I set up for series so it’s putting 12V to the parallel triple 9V MT-G2, works like a charm. 
Edit II: This info was less a brag and more of a nudge for folks to think outside the box with these new drivers.
LOL 
Look what just arrived!
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I don't believe you 
Nice! They looks so clinical and professional 
@led4power and @James3: can you please let me know if the Low and Medium modes are fixed at 120mA and 1.2A, or whether they are 2% and 20% of the maximum current?
They are 2% and 20%.
which resistor value do I need for 12A setting?
Thanks!
It's 76.8K.
I thought 76.8k would be for 9A. I want to go for 12A
Equation for max. current set resistor is:
Rset[kOhm]=~900/Imax[A]
So,for example for 6A->150kOhm(default),9A->100kOhm,12A->75kOhm,5A->180kOhm etc...
A dumb question, but will the LD-2 work with both forward and backward clicky switches?
Which ones are the standard on/off switched on lights with separate on/off and mode switches?
Good answer from DBCstm to your question:
Yes but it seems I did not ask the right question.
so
I see I did not clarify my question.
My question is “I have a friend” who has lights that once upon a time had a forward clicky (on/off) + a magnetic ring (mode selection)(that for whatever reason the mode ring along with the driver is/are now dead) so no hope of “factory” modes, Would the LD-2 work?
Or maybe I should ask, other then turning it on and off will the forward clicky (typical on/off only switch) will the LD-2 give me control over modes using the existing tail cap switch?
Thanks again for your help.
And thank you for the follow up.
As HKJ tested, LD-2 produces over 7W of heat with MT-G2 at 9A. Does it survive long term usage with MTG2/XHP at 6A in open air without cooling (floating inside flashlight head) ?
It strongly depends on batteries used. With low drain,or 18350 batteries,6A shouldn't be a problem,because of larger voltage sag,but putting driver "so it floats inside of flashlight" is not a good idea,max. allowed dissipation in that case is ~1W.
Thanks. I know it could be a problem but needed confirmation.
Offtopic: Plan was to use it floating inside Olight SR51.
What are the dangers of not using the ntc sensor if any?