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

My plan is 3.85A Nanjg, custom programmed, domed, so we'll see if I can make 100 kcd w/domed but at higher amps with the XP-G2. My usual C8 builds are 3.85A with copper discs added, so think it will be ok for the T20 (my builds are typically pushing it ). At those high amps, I've found the Pana PD 2900 is excellent to get full amps for 3.85A with XM-L2/SinkPAD combos, and the Samsung INR 1500 I got from FT is actually a little better.

I used to think the same thing (de-dome for reflectors but not aspheric), but DrJones’ post about this topic claims that throw is increased for aspherics, too.

I dedomed an xml2 for my 7g5v2 and that made a huge increase w/ the aspheric lens.

I get 180k lux @ 1m (measured at 13ft). It has slightly higher current than stock because I upgraded driver wires, and I am using a copper sinkpad. When it was in stock config my measurements were slightly lower than selfbuilt’s numbers for the 7g5v2.

Really?? Do you have a link to that post? I’d love to hear what he wrote about that. I think it’s awesome that it increased output on your 7G5v2. Sure doesn’t make sense on the surface but I’d love to be wrong about it. I may have to arrange for the same mod on my UF-T20. :bigsmile:

20mm pads have been ordered. My already xp-g2 modded T20 will be getting copper and 2.8a in the near future!

Thanks for the detailed post and awesome mod!


Wow. The XP-G2 continues to impress me with its flexibility. djozz, I think you’ve even usurped the DEFT-edc for size/throw.

last paragraph of first post for a direct comment Flashlight Optics - Dome, Dedoming and Throw

it didn’t make sense to me either, until I re-read his entire post a few times lol

edit: also, i might add, dedoming made the 7g5v2 reflector head somewhat useless for me. the spill is so dim that I might as well use the aspheric…

Well, that would have been nice, the DEFT-edc has about the same length, but the head diameter is 33.6mm versus 44mm for the UF-T20, the weight is 114 gram versus 174gram for the UF-T20, so it really is a bit smaller. The throw of this build is better though, the DEFT gets to 86klux, I measured 108 (I guess that if this light gets a bit better battery and used a cool white led instead of a 3C it may get to 130klux ). So I'd say it's the same league, which is already very nice for a light that has costed me 32 dollars alltogether.

Sorry, still having fun with the light . Want to share this pittoresk rainy beamshot I just made (just before going to sleep). (According to google those two tiny trees in the hotspot are 83 meters away). Good night to you all !

Crap - I gotta get this T20 mod done!

I just finished a C8 mod: XM-L2 T6 0D/SinkPAD, Nanjg 3.85A. Best #'s after doing the solder flux wick (ooops!) mod to the tailcap spring (picked up 60 lumens btw...), got 1230 @start, 1200 @30 secs on a fresh Panasonic PD. This is only 30 lumens less than a C8 XM-L2 U2 1C/SinkPAD on the same battery, same fresh state, same driver, etc. The T6 0D is clearly a bluer beam pattern though, but I've seen worse XML T6's.

Update 03/20: T20 mod Done! Upgrades: Nanjg 3.85A, 2 copper discs soldered in the pill, XP-G2/SinkPAD, sanded down to fit tight, added solder wick to both springs, replaced switch and rubber boot (blue GIT).

Before mods, stock: fresh Pana B unpro, 3.7A measured, lumens: 731 @start, 615 @30 secs, throw: 34 kcd

After mods, fresh Samsung INR 1500, 3.89A measured, lumens: 670 @start, 646 @30 secs, throw: 75 kcd

Just not sure of XP-G2's bin/tint, but not bad results. In theory, maybe would get 150 kcd dedomed, but I'm still working on a successful dedoming...

Here's some photos of the build:

Did two 3.85A Nanjg drivers together, one a C8, other the T20:

On the left is the T20 pill orginal pill, on the right is a C8 pill all polished up:

The T20 pill prep'ed and the SinkPAD all prep'ed and sanded down. For the contact surfaces, I sand starting at 220 or 400, then go all the way to 2500 grit to get them perfectly polished for a smooth contact with thermal grease:

There are 2 copper discs in there, soldered in using solder paste and a torch:

Assembled, tested. LED wires are 22 gauge, silver tinned, teflon coated.

djozz - really liked your picture of this view so stole your idea and did the same shot! It is impressive showing people this direct look at the emitter and SinkPAD.


That is some nice soldering on those nanj piggy backs. Care to put forth any tips on how you get the solder to span the gaps between the pins so neatly?

I can do it once in a while, but most often I end up using a piece of wire.

Those additional 7135’s do look great. Any soldering tips would be greatly appreciated.

Also, can you post a link as to where I can buy some copper disks?

that is some neat soldering there, impressive! Nice also to see the difference between +dome and -dome in the same flashlight, I suppose the measured lumens are done when zoomed out? And you have done the things I have neglected, like improving the conductance of the springs and improving the switch.

Thanks for the pictures too , I appreciate it when the pictures are well done .

Getting lots of practice with that soldering. Thanks all for the appreciation! Gotta get to work - will provide details and answer Q's.


- lumens measurements, yes -- lumens measured at full flood position, sorry didn't mention that

- soldering: I have a Hakko iron, ~$90-$100 I believe, using the stock tip which is a small flat tip - don't use a pointy one -- too difficult to get heat on the legs, and keep the iron tip clean, always before use (use the wet sponge thing). I use a bent needlenose to bend over all 3 7135 legs at the same time, quick, simple, easy, works every time. For the soldering, I cheat somewhat. First apply flux to the base 7135 3 legs (use the pen type applicator) and get some on the 3 legs of the top 7135, position the top 7135 in place (no adhesive of any kind), use a tweezer in one hand to hold down the top 7135 in place, other hand is the iron with solder applied to one side of the tip - be sure to use enough, not too much - hard to describe.... Then I try to first touch the base leg then sweep up to the top leg - try to get solder on first, then use upward strokes -- too little solder on the iron result in not getting enough solder on the legs, too much solder, you may get big problems with a blob. Oh - I'm putting the driver in a table top vise and using drug store type magnifier glasses (think 2.0 or 2.5) - that's all. Once it looks good, I inspect with a 10x lighted pocket magnifier, when all done, do full continuity checks. I always solder all 3 legs, then do the back connector - for the back connector/leg, big blob of solder on the iron, tilt the vise back so gravity helps and also easier to see and work on (also tilted back slightly when doing the front 3 legs). Also in doing the back connector/leg, be sure to still use the tweezer to hold down the top 7135, and also important, do not hold the iron on the connectors - can cause the entire bottom 7135 to slide off it's pads (happened to me once or twice)! So, short contacts with the iron , stroking up/down to fill the gap. I know pics would help with this, hope everyone can follow this....

I always clean up the board with alcohol on a stiff brush afterwards (using a brush from an old electric razor) - gets rid of the flux stains, think that's why it looks so purty in the pics .

Forgot to mention: I use the iron at 750F temperature, little hot but found this to be the best for me...

Nice pics Tom! You almost hate to install that kind of work. I just like looking at it!

Nice numbers also!

Thanks for the explanation Tom E. Nice work.

Man, FastTech has been a total game-changer, this driver, programmable: 8-amc7135-2-group-25-modes, this deal on 7135's: amc7135-350ma, and this for programming: https://www.fasttech.com/products/1002900. Incredible prices....

djozz - great job on the light, especially soldering the star to the pill. I probably would have done the star first and then reflowed the LED on top, but I doubt it makes that much difference.

TomE - I agree about fasttech, I just got one of those USBasp programmers. Just waiting on my clip to arrive from Digikey and I can start programming :slight_smile:

Thanks for all the super useful information you provide all the time.

What clip do you use to connect to the actual chip?

Yes - this is the tricky item to get it working. Looks like mattthemuppet got it from DigiKey, I got mine off of eBay as recommended in the big "perfect modes" thread here: http://www.ebay.com/itm/ws/eBayISAPI.dll?ViewItem&item=281052883176&ssPageName=ADME:L:OC:US:3160. I noticed this link has sold out, but maybe the seller has another updated posting? This clip cable had to be modded - I changed the 10 pin header because the wiring of the 8 to 10 was dropping pins 1 and 2, then also, pins had to be swapped around on the clip side - that part is easy, but you need to know how to map the pins. There should be other sources for this clip on eBay as well.

I got this one
as it worked out about the same price (I was getting other stuff from Digikey) and I’d be able to start futzing around in a few days rather than a few weeks :slight_smile: AFAIK it’s the same thing as the one Tom linked to, just without the cable (which you have to change around anyway).