Uniquefire UF-T20 mod: 3.05A xpg2-3C dedomed on Sinkpad

This thread by tecmo kept me busy: 100klux in a pocketable light, is it possible? I thought for a while about good hosts, suitable leds, Sinkpads, right amperage, but what still would be a sensible and usefull flashlight (I'm not scaru I'm afraid, I'd love to be scaru but Im just not him ) and decided on the following build:

This is as small as I could made it and still have a usefull flashlight:

It is the Uniquefire UF-T20 aspheric. It is a relatively small 18650 aspheric, but is it really pocketable? For me it is not, but for some others it is.

The stock light is well build, but comes with a XM-L led. Some claim that it is a good thrower, but I think the throw of the stock light is pathetic, I did not have one by hand, but I'm sure it is out-throwed by the Sipik sk68, even though the light I received ($20,97 Manafont) runs the XM-L properly at 3A (it did give off the weird smoke that some others have described fot this light by the way, don't think it is the lube, rather the heatsink glue).

You just don't want an XM-L in your aspheric thrower!

But apart from the wrong led and the initial smoke this light is nice: everything is solid, it can dissipate the heat from a led at 3A (unlike most (all?) other XM-L zoomies), the glass (some have said it is plastic, but it actually glass) aspheric lens has a decent curvature (=short focal length=>still close to the led when fully zoomed in=>so still cathes a good portion of the light when zoomed in) the actual used diameter of the aspheric lens is a solid 32mm (bye bye Aleto ), and it looks to me much better than any inflated version of the Sipik sk68.

I still had the XP-G2-3C at hand that I accidently had dedomed (living for a while quite nicely in a Romisen RC-G2, sorry Romisen..), and I really like the tint of it (~4000K), even for an extreme thrower I want my tint right . I reflowed it on a 20mm copper Sinkpad, had to sand the sides a bit (the UF-T20 pill has only room for 19mm) and decided not to use thermal paste but just reflow the whole thing onto the brass pill; good for heatsinking and it saves me the trouble of screwing down the board:

As you can see at 1.05 minute the solder paste melts and the board sinks in a bit. Unfortunately not really level, so after this video I heated the pil up once more and while still hot I pressed the board down on the pill with a forceps. I added a 3.05A Nanjg 105C driver, a blob of solder between driver and pill for electrical contact (brass pills are nice to work with!) and the flashlight was good to go:

beamshots: resp. flood at 2m, zoomed at 2m, zoomed in at 5m, outside tree=30m, outside grass=100m

You can see the clean pencil beam. I did not have to blacken the area around the led because the led was dedomed, so no light is scattered backwards to the board via the dome. Sorry for the hasty outside shots, I think my neighbours find me weird enough for now.

And now for the numbers:

The estimated output in lumens (calculated from ceiling bounce readings), with a freshly charged Panasonic CGR18650CH inside:

flood 440 lumens, zoom 280 lumens (=a decent 63% of the flood output)


I did a 10 minute testrun, after 10 minutes the light did not become any hotter anymore, so heat production/dissipation had balanced out, it was hot but still not too hot to touch.

Throw is a lux-measurement of the hotspot at exactly 1 meter from the top of the lens. (I also tested at exactly 2 meters and those readings were a precise 4 times less (I measured 27.000 lux at start), so I decided measuring at 1 meter give correct numbers ).

I have the impression (I don't know why) that my luxreadings are on the low side (luxmeter: Tondaj LX-1010B). I have never been able to calibrate it to a known light source. (Fun: this luxmeter claims on the housing to measure up to 50.000 lux, but the actual reading goes over 100.000 no problem)

The tailcap reading at start was 2.97A, battery loaded to rest voltage 4.21V

throw at start: 108 klux

throw at 30 seconds: 107 klux

throw at 2 minutes: 105 klux

throw at 5 minutes: 101 klux

throw at 10 minutes: 101 klux

The tailcap reading after 10 minutes 2.62 A, battery rest voltage 3.87 V


It appears that this build is indeed able to throw over 100.000 lux@1meter, jeehaw! And the light is still kept usefull: runtime on 1 18650 will be about an hour on high (depending on battery type), the light can indeed run on high for longer periods while maintaining output (so the heatsinking is good), and whenever you don't want a pencil beam (this may just happen occasionally ) there's always a nice 440 OTF lumen flood option.

I have almost forgotten the beam of this light when it had the XM-L in it .

Thanks for reading!

very nice build.

the stock pill has a raised 16mm pad. did you machine that down or just leave it so there is an air gap around the outer edge of the 20 mm sinkpad? the lens in the ones i’ve built are 38.02 mm. yours is 32mm?


There was indeed a raised 16mm pad, i left it like that, I reckoned that a 16mm diameter solder joint was more than enough for the heat to get away and the brass under the gap was thick enough to maintain a good heat-path.

The lens when taken out of the flashlight is indeed 38mm, but in the flashlight, with the retaining ring in place, 32mm is effectively used.

Very cool! Good job there. I’d love to have a lil thrower like that.

My plans have been wrecked from the start. I ordered a UF-V3 type light from DX and they sent me an aspheric. I ordered two 16mm xp-g2 from ff and they sent them to me on 10mm stars.

Thanks djozz for the video and the mod.

Thank you Tecmo, you were the start of this. Hope your plans come together soon, the UF-V3 seems like a very good light. High time you learn how to reflow leds then .

do you have any stock lights or maybe a c8 to compare readings to? nice light by the way. over 100k is good numbers. i was just hoping for something to compare my thrower lux to when i get my meter, as im sure my meter will be less than accurate lol

Reflow?? I almost blew up the light I did mod with a simple soldering job :slight_smile: At least I’m 2 for 2 on dedomes.

agreed, 16mm solder joint way better than white goop. soldering that sink pad to the pill is an awesome idea. i bet you start start a trend with this :wink:

I'm sorry, nothing is stock anymore when in my posession for a while . And I'm the only flashaholic who does not own a C8 (don't like the design).

My ceiling bounce lux-readings are always compared to a Thrunite Ti with a fresh Duracell alkaline (that is said to output 60 lumens), to convert them to lumens. So the lumen numbers are not very accurate, but I would be surprised if they are more than 10% off.

Has anyone here on BLF actually calibrated their luxmeter? Is it doable at all?

lol… i think im the only one without a working p60 host or an sk68… same reasons

you are not alone. i don’t have a working p60 host(as long as enough parts to put one together doesn’t count) or an sk68 either…but i do have two c8’s!

Thank you for such a great detailed how-to post. I have 3 T20’s and have been rather pleased with their stock performance. But now after reading your post, Im completely amazed with your results in such a small and easily modded package. Your reflow of the sinkpad directly to the brass pill was brilliant! In an age with more and more AL pills, its nice to still find some made of brass. I have 20mm sinkpads and some 16mm on order. Thanks to you and tecmo, we all now have a relatively easy conversion for the cheap pocket mega-thrower. Also, I didnt realize the lenses were glass. They are all very good quality in the 3 examples I have, as are the hosts. I also agree with your observations about the heat sinking. Even when not on sale, these lights are still a great bargain. IMO, buy them before they change the pills to aluminum. Those are usually the first changes they make when trashing a once great light. Next will be the lens.

I just realized that my T20’s were purchased at wallbuys… I hope the pills are brass. Anyone know?
Edit - its brass. :slight_smile:

Probably a silly question, but after your mods, are you happy with the lights performance at the fringes of its range? In other words, does it throw photons way out there?

That looks cool. Now I'm thinking if I should do the same with my Smallsun ZY-C10.. but its made for XRE. :/

Great mod, I love it. The UF-T20 is a great light to mod. I have a direct drive single mode XRE R2 in mine mounted to my scoped rifle. It easily out throws anything else I have, plus I like the fact that the zoom is threaded so it won’t zoom out from the recoil of my .308.

I got a stock T20 from WallBuys, and yes, it does have a brass pill, actually it's a C8 sized brass pill, so got some flexability there. I got an XP-G2 on a 20mm SinkPAD waiting on what to use it on - this sounds perfect, though it's got the dome.

Hey its E1320! How you doing?

Im with you on that nightcrawl do the same thing to a C10. I personally like the C10 better, in the looks and it performs better then in the xre (green) department.

Put it in Tom! Interested in whats the difference in dome and no dome!

thanks for posting this. I’ve been considering almost the exact same mod. I already did the sinkpad soldered to brass pill with a green xpe, but for the next one I’m going with white, but haven’t decided which emitter.

I think I’d prefer xpg2, but I might do xml2 with everything else the same (though I prefer 5000k) so we can compare numbers.

Haven't been camping with it yet, just annoyed some neighbours by searchlighting the little square I live in. I have a reflector based budget thrower build (49mm reflector, dedomed xpg2, 2A) that throws 70 klux, and I don't like the spill much because everything in close proximity is lighted up as well and so distracts from what you want to light up in the distance. This one effectively has no spill at all. And I can also hearthily recommend a neutral tinted led for a thrower like this, very nice in the outdoors.

But to directly answer the question: o yes, those photons get there alright! Huge fun!

Simply amazing results! I can't help but think that it would be even better if the LED was not dedomed. Dedoming works great on a reflectored light because it's the spread of unfocused light from the LED hitting the reflector that helps focus and throw the light down range. In an aspheric light you want the light from the LED focused into the center of the lens, not the walls of the head. Leaving the dome on the LED should focus more of the light into the center of the lens than the same LED without a dome.

I had an XR-E ftt light that I accidentally dedomed and it ruined the output in comparison to when it still had the dome.