Doooooooooohhhhhhh I just got mine last week ! This driver rules BTW
So I ordered the MTN-MAXlp driver, choosing the 5.1AMP version along with an XP-L V6 3D LED on Noctigon 16mm MCPCB and a XM-L2 T6 4C LED on Noctigon 16mm MCPCB for experimentation. In stock form the copy of the UF-1405 that I got from GearBest can light up a freeway at a distance of about 700 feet from above, and that’s at a tail cap rated .74ma. At 5100ma this should be a friggin white laser! Maybe on a clear night I can blast a beam across the Columbia Gorge outside Portland, Oregon. My favorite place to test lights is at the Vista House.
ANy other driver option( exept MTN-MAXlp ) for 1405? The default driver died pretty fast though
It depends on what kind of emitter you’re gonna use.
For 3V emitters, I’m afraid there is no other good choice other than Richard’s MTN-MAXlp, unless you somehow modify the pill and make it to accept 21mm driver.
For 6V emitters, the simplest yet effective route would be zener-modded linear driver.
Hmm… anybody tried Mtg2 inside the 1405? Dedomed or not
I used Richard’s 17mm MTN-MAXlp HP driver in my 1405 driving a dedomed XP-G2 S2 1D at 4.5A, producing 403kcd using the measuring distance of 4.5m.
Here are some pictures including poor quality beamshots (I used my smartphone to take the beamshots). Click on the pictures to view the full size. Descriptions are at the bottom of each picture.
Building the driver by myself and it is definitely not an easy task for me as this is also my first driver building. Gotta give credits to Richard for his helps along the way. 
Lightsaber shot. It is very hazy around here recently. 
But it also makes the beam much more visible in the air.
Control shot. The building is about 300m away from where I stood.
The haze was heavy but the light still hit the building anyway, easily.
Just another one. You can’t really see the hotspot on the building due to the messed up exposure, sorry about this.
Gotta say that the 17mm MTN-MAX is an excellent driver and also seemingly the only solution for the 1405 at the moment. I might be able to get better lux readings with 5A current, using the latest XP-G2 S4 2B and measure at longer distance.
10x for sharing your experience m8
Well I received my package from MtnElectronics yesterday and got it all soldered and installed tonight. In stock form at full brightness it had a tail-cap rating of 0.74amps. It now has a tail-cap rating of 3.69amps, which is weird as I chose the 5.1 amp driver, but I guess I’ll chalk that up to resistance loss. The driver I received had a short length of 22ga. silicon wire running from the base of the spring to the top, so I copied that design to the tail-cap spring. The light is now MUCH brighter and after 30 seconds the head of the flashlight gets very warm, which is a sign of good thermal coupling. Now to take it up to the Vista House just outside of Portland Oregon in the Columbia Gorge to check out its new throw. _
When I receive my XP-L HI noctigon from International Outdoor Store next week, I’ll playing with it too and track its output.
Buck drivers are not 100% efficient, and most of the good buck drivers are having 70% to 80% of efficiency only. I have not verified what is the efficiency of Richard’s driver, maybe he can chime in on this.
Beside that were your batteries fully charged (i.e. 4.20V)? With buck driver as your batteries discharge and their voltage go down over the time, the drawn current will increase. This is exactly the role of a buck driver - To regulate and ensure that the total wattage is always constant. I have a 17mm MTN-MAX from Richard too with the 4.5A option, and with my fully charged Sanyo the tail reading was around 2.52A, but as my batteries discharged further the tail reading would increase to 2.80A something, and this will go on until the batteries are (almost) fully depleted.
I use Efest 4200mah 26650 batteries and both were freshly charged to 4.2 volts. After some beam tossing and estimating throw distance via Google maps, this flashlight went from throwing about 700ft to about 2500ft! Can’t wait to see what the XP-L HI is gonna do for this light!
I do have a question. When soldering the driver to the aluminum pill, do you solder around the entire perimeter? I only soldered about 50% of the way around like the stock driver was soldered.
With a buck driver on two li-ions in series, the tail current is not equal to the led current, with 3.69A at the tail, the led may very well receive the promised 5.1A.
What LED are you currently using? With dome on?
I just press fit the driver in the pill and it works fine, didn’t do any soldering on the perimeter at all. As long as the driver makes good ground contact with the pill it doesn’t matter if you want to do the extra soldering or not.
The current led is the Cree XP-L, but I have the XP-L HI coming next week. I only soldered the driver in because the stock one was and I didn’t know if it was going to make good contact. Plus I figured that it couldn’t hurt.
High performance buck drivers get much hotter than other drivers. It needs to be soldered for heat transfer
In that case, when I get my XP-L HI, I’ll solder all the way around. It’s not easy soldering to this pill though. It wicks the heat away from where your trying to solder too fast!
I made a mtg2 dedomed pill with mountain max driver and a dedomed xml2 with Richard’s 5.1A driver. The mtg2 gets 150kcd and the xml2 gets 350kcd. Even though the mtg2 throws a lot of light I still have the xml2 in the light 99 percent of the time.
I also read 3.8a at the tail on the xml2. And about 10a with the mtg2.
Yes high performance buck driver runs pretty hot that’s true, but one thing that I am not sure about is whether the pill is hotter or the driver is hotter in this case? If the pill is much hotter than the driver (due to the overdriven emitter) and the driver is soldered on the pill, then I’m afraid more heat will be transferred to the buck driver instead.
I’m not aware of any test like this yet, so what I said above is just my feeling and I could be wrong.
I have heard this one before and it is a misconception: if the driver has no other significant drain path for the heat (air and the battery spring will not do it for a 5A buck driver), the pill has to do it anyway, hot or not, or else the driver will just keep getting hotter and eventually also hotter than the pill, because heat will be generated and it can not get away.
I think it makes sense now, thank you djozz.
What if I don’t solder the driver to the pill but using one of these silicon rubber cubes ? Do they cut it?