3W Surefire U2 Mod - Is it Possible?

I absolutely LOVE my U2 and EDC it.

I was wondering though,
would be be possible to mod one to use a 3W led?
The longer runtime and greater throw would make it an Excellent counter part to the stock 5W U2.

Anyone tried this?
Problems I can see are,
Stock board not modable to drive the 3W led.
Stock reflector not making a nice beam with the 3W.

Thoughts?
~John

I believe one member did just that,cannot remember who though.
But it looked like it worked great.


If you are one of the lucky to have a working U2,why dont you keep it stock.And when it stops working(It will eventually)you have the warranty and can send it to SF for repair.

I think you are better off just buying a Kroma




My 00,2 lumens.


Benny

I think it was grnamin who did this, but not sure. The problem is that with the circuit in the U2, if the Vin is much greater than the Vf of the LED, you are in direct drive and the lower levels can't be selected. So you could use an 18650 to power the Lux3 mod, but with a freshly charged cell you might not be able to turn down the current until cell voltage drops a bit.

I am not wanting to mod mine to 3W,
if I did this, I would get a second U2 for it

I use 18650s or Pilas in mine all the time,
I dont use primary cells anymore.

I fugured the board was gonna be the problem.

The Kroma? ehhhh
I am not all that impressed from what I have heard, and its price.
I VERY seriously doubt the optic is gonna make a beam I like.
I dont really have a use for colored leds.

~John

Well i cant wait to get my Kroma,


Think of the Colors as a bonus.
The price aint to bad either,i payed 240 USD for mine shipped.
And if Al is correct about the beam pattern on the Kroma,it will be awsome.
Nice hotspot with plenty Flood.

I believe it was very similar to the output/beam of a E2E/E2D if i remember correctly.




Benny

I am wanting to see the beam, very interested if the finally got an optic looking good.
But I am sceptical.

Interesting thought on a 3W U2. But there are many truly fine 3W lights out there....

The Kroma.. I dunno. Somehow the K2 doesn't light a fire underneath me. There are probably many who think I'm a Surefire nut who has to have everything they put out, and that's ALMOST true but the K2 seems to be the exception. L1/L2 style switching completely does not appeal to me.

Benny: Do tell us about the K2 though, I'm still interested in hearing about it though I'm not willing to cough up $$ for it at the moment.

many other fine 3W lights out there?
true, IF you dont want multiple level output.

Sure, theres the HDS and Arc4
I have an Arc4, like it alot, but I would like and use a U2 style 3W light alot more.
I dont care for single 123 cell lights, the rechargable 123s just arent cutting it.
I have been stuck on 18650s.

I also REALLY like the physical user input of the U2's rotating colar.
Much better than the click click press press tap setups.

~John

jtice,

I'm willing to bet that milkyspit could make it work. It's just a function of having the light and wanting to do the mod. I've always wondered about a nicely binned U-bin in a deep reflector like the U2.

Some of the higher Vf U binned LuxIII's would work, I think.

PM milkyspit and see what he thinks. He has my U2 right now looking at some possible options, but swapping to a LuxIII isn't one of them.

Bill

I think the levels were whacked out with the luxIII. Like small jumps in some levels, and larger ones in others. And the last 3 low levels weren't there or were all the same.. But hey put one of the L vf K2's in there with the redicously high ... er low efficiecny and the wattage should be as high as luxV! The levels might work then. I wonder what the vf would be at 1.5amps? close to 6v? haha.

IIRC in the mod the driver was the problem and some levels didn't work, and I do not know if it was really that bright either. And the driver won't yield easily to moderation I think

In the same size class you can now have a McLuxIII-27LT that drives a UX1K at 917 and 100mA drive levels, both fully regulated. Consider it a hybrid of the McLuxIII-PD and the HD45:






It has a concentrated and powerful beam with the new McR-27L reflector:



Comparison of the coronas:




bernie


P.S.: touching the U2 is sacrilege! :nana: :whoopin:

Yea, figured the board would be trouble
Think I recall now, the levels not working correctly.

OUTSTANDING Beamshots there Bernie !!!!! :rock:

Does have a nice beam,
I have been looking at the A3s alot, seems to be more throw, less wide spill?
But with a smaller dia.

~John

Can't really comment on the lux readings of the spots because there is the Lottery at play in the beamshots, but I think the A3 should have more lux than the 27LT ... but the corona of the 27LT makes more than up for that when the usefulness of the beam is concerned. At least IMHO.
Note though that the A3 itself has a nice and bright corona, too. In my very personal opinion the A1 is the looser here as it wastes so much light in that huge and pale corona ... its only point is the very small size and good throw.

But ... there are a lot of choices , and to each his own! Flashaholic life is good these days

The 27LT's beam is even tighter than the U2's.

Honestly though ... to stay more on topic ... I'd wait for the Kroma reviews and pics before committing sacrilege and using a LuxIII in the U2.

bernie

The PR reflectors in the PR and PR-T heads, make one of my all time favorite beams.
They have VERY wide spill, with a very tight spot, especially for its diameter.

I like the A3 beam, but the not so wide spill if a bit of a turnoff.
But, if I got an A3, it would be for the purpose of throw, so, I guess the loss of wide spill is a worthy tradeoff.

~John

Interesting thread! Now you all got me wondering if this could be done to an L5, since it is just one level to begin with. That big reflector in relation to the smaller die should make an awesome tight hotspot. I also have the McE2S 2-stage tailcap switch on my L5 right now so that would give me a low....

Hmmm.... Lux III in a L5? Whaddya think?

Guys, Guys, Guys!!

ANYTHING can be done!! It just takes time and money!! As I said, this one is right up Milkyspits alley, and he has the time to figure it out right now.

Remember, he was laid off recently!!

Talk to him, see what he says, but I bet it can be done with either a high binned LuxIII or maybe a K2.

The main problem is that the U2 is such an expensive host to mod that no one has really wanted to mess with it.

Now a comment on Kiesslings beam shots. They are, as always, impeccable.

For me, the AlephI was by far the most usable, BUT my favorite was the AlephIII. Don did some magic with that reflector, because I never found a reflector, even 3" in diameter, that made a tighter, better thrower than that.

Someone out there has my Ubinned, 1500 mA AlephIII that throws like a monster, and it is a sight to behold!

The 27LT looks like a great light, too.

Bill

Wow Bernie, those beamshots are nice! I'm loving the 27L, looks way tighter than the 27, and with brighter spill. Gives the A3 a run for it's money! Rockin.

Bill: 1.5amp Ubin, wow, I bet that's a scorcher! The 27L for it's size though is a throw king!

The 27LT has the tightest beam and brightest corona for sure, but as long as the Lottery is at least roughly fair, it does not have the hottest spot. The A3 should have more lux values. I think.
Thanx guys!
bernie

IsaacHayes said:

Wow Bernie, those beamshots are nice! I'm loving the 27L, looks way tighter than the 27, and with brighter spill. Gives the A3 a run for it's money! Rockin.

Bill: 1.5amp Ubin, wow, I bet that's a scorcher! The 27L for it's size though is a throw king!

Click to expand...

That 1.5amp U bin was the only LED I'd had that would put appreciable light on my reference tree, which is 250+ yards away. That is until I got the MR-X which will do it and put a lot more on it.

Bill

I think this is a very viable mod if you intend to stick to 18650 or 17670 cells. The circuit is a boost so the input voltage must be lower than Vf + a diode drop. What you'd want is a medium to high Vf Lux III (Photonfanatic has some UX1N). If anyone is willing to be a guinea pig and supply the U2 and the LED and pay for shipping to and from me, I will supply the labor. I will try to see whether the nominal bias can be boosted such that the LED gets close to 1A on high. No guarantees though. I'm not about to risk scratching a U2 to try to open it up. If I can't do it, it will be returned un-modified.























Damn, did I really sign up for this?