# Surefire U2 Ultra XP-G2 mod



## Nitroz

I recently modded this U2 with an XP-G2 emitter, 3D tint(5000k). The results versus the original P4 Seoul are so much better. To me the stock LED is weak and has a very cool blue tint.

Enough rambling and on with the pictures.

Removed the control ring in preparation for heating.






Head separated.





Stock LED removed, and cleaned for new emitter.





XP-G2 installed.





Light re-assembled


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## think2x

It makes me wanna open mine up, How's the Beam compared to the SSC P4?


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## Nitroz

think2x said:


> It makes me wanna open mine up, How's the Beam compared to the SSC P4?



It's night and day! Here's some crappy cell phone pic of the XP-G2. The tint is so much better.
This is level 3





This is full power


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## Tana

Very nice mod on a beautiful host... makes me want an U2 now...


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## Nitroz

Tana said:


> Very nice mod on a beautiful host... makes me want an U2 now...


Thanks! All I can say is, do it!

The only thing that would be nice is for the high to be 1.5 amps instead of about 620 mA at the tailcap. It is still a huge improvement over the P4 Seoul.


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## Tana

Nitroz said:


> Thanks! All I can say is, do it!
> 
> The only thing that would be nice is for the high to be 1.5 amps instead of about 620 mA at the tailcap. It is still a huge improvement over the P4 Seoul.



620mA at the tailcap with Surefire's buck driver would give 1A to the LED... so OTF should be about 300 lumens with XPG2 R5... and it will run for 2 hours that way... 1.5A at the tailcap would seriously overdrive the XPG2...


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## Nitroz

Tana said:


> 620mA at the tailcap with Surefire's buck driver would give 1A to the LED... so OTF should be about 300 lumens with XPG2 R5... and it will run for 2 hours that way... 1.5A at the tailcap would seriously overdrive the XPG2...



I guess I should have made clear that I would like to see the 1.5A at the emitter and not the tailcap. With 6 modes though I think a high should be just that. Just dreaming.


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## Tana

Nitroz said:


> I guess I should have made clear that I would like to see the 1.5A at the emitter and not the tailcap. With 6 modes though I think a high should be just that. Just dreaming.



Oh, that's easy... just swap the driver as well... :devil:


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## cubebike

Nice! I have U2 sitting on the shelf collecting dust at this moment! I never modded any flashlight before! Might give it a try! Looks like the XPG2 die a bit too small for the reflector ? Should I go for XML2? I have no idea about the current, driver and Vf stuff like that! Looking forward for some instructions !!


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## Tana

cubebike said:


> Nice! I have U2 sitting on the shelf collecting dust at this moment! I never modded any flashlight before! Might give it a try! Looks like the XPG2 die a bit too small for the reflector ? Should I go for XML2? I have no idea about the current, driver and Vf stuff like that! Looking forward for some instructions !!



You could go with XML2... especially shaved or dedomed for smaller hotspot and better throw... but XPG2 is ideal with stock driver, imho, just like what Nitroz did... and you get better throw, compared to Malkoff M61 for example, because of bigger reflector...

That beamshot looks really nice... definitely a great EDC now...


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## Justin Case

Tana said:


> 620mA at the tailcap with Surefire's buck driver would give 1A to the LED... so OTF should be about 300 lumens with XPG2 R5... and it will run for 2 hours that way... 1.5A at the tailcap would seriously overdrive the XPG2...


 I measured 915mA drive in my U2A that I mod'ed.


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## Tana

Justin Case said:


> I measured 915mA drive in my U2A that I mod'ed.



So two different drivers used... (I doubt that different emitters would create such a difference with the same driver)... Did U2A have P4 Seoul emitter as well ???

So basically, you have what Nitroz wished for...


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## Justin Case

Tana said:


> So two different drivers used... (I doubt that different emitters would create such a difference with the same driver)... Did U2A have P4 Seoul emitter as well ???
> 
> So basically, you have what Nitroz wished for...



No, Nitroz wanted 1.5A drive. I measured 915mA drive. Yes, CPF nomenclature for the U2A means the Seoul P4 version, not the Lux V boost driver model.

You apparently are confusing tail current draw with drive current.

FYI, swapping out the driver looks like a non-trivial task. The driver is a two board design, with the bottom board implementing Hall Effect sensors, which provide for the multimode switching through the selector ring. I don't think you'll find an off the shelf replacement for that driver if you want to retain multimode control through the ring.


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## tobrien

awesome work! so you didn't need to put any copper shims under the XP-G2 or anything?


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## Nitroz

Justin Case said:


> You apparently are confusing tail current draw with drive current.
> 
> FYI, swapping out the driver looks like a non-trivial task. The driver is a two board design, with the bottom board implementing Hall Effect sensors, which provide for the multimode switching through the selector ring. I don't think you'll find an off the shelf replacement for that driver if you want to retain multimode control through the ring.



920 is what I measured on that U2. As far as changing the driver, no way! It's a great design.



tobrien said:


> awesome work! so you didn't need to put any copper shims under the XP-G2 or anything?



No shim. The beam looks much better than the P4 so I left it at that.


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## Justin Case

Nitroz said:


> 920 is what I measured on that U2. As far as changing the driver, no way! It's a great design. No shim. The beam looks much better than the P4 so I left it at that.


 Thanks for the confirmation that the drive current is in the low 900mA range. I found that if you use a 2mm thick MCPCB (such as the 10mm diam Cutter boards) under an XP-G or XM-L, then you don't need a shim to get the LED die to the right focus height. But if you use an 8mm diam round MCPCB, those are typically 0.8mm-1mm thick and you do need a shim to raise up the LED die.


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## Nitroz

Justin Case said:


> Thanks for the confirmation that the drive current is in the low 900mA range. I found that if you use a 2mm thick MCPCB (such as the 10mm diam Cutter boards) under an XP-G or XM-L, then you don't need a shim to get the LED die to the right focus height. But if you use an 8mm diam round MCPCB, those are typically 0.8mm-1mm thick and you do need a shim to raise up the LED die.



It was a 10mm round, 2mm thick board I used and dremeled it down to 8mm round. That looks to me like the sweet spot.


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## Redhat703

This is a beautiful mod! It makes me want to mod mine as I have 3 U2A's. I have a question: does the Nichia 219 LED fit in?


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## Tana

Justin Case said:


> No, Nitroz wanted 1.5A drive. I measured 915mA drive. Yes, CPF nomenclature for the U2A means the Seoul P4 version, not the Lux V boost driver model.
> 
> You apparently are confusing tail current draw with drive current.
> 
> FYI, swapping out the driver looks like a non-trivial task. The driver is a two board design, with the bottom board implementing Hall Effect sensors, which provide for the multimode switching through the selector ring. I don't think you'll find an off the shelf replacement for that driver if you want to retain multimode control through the ring.






I presumed you measured at the tailcap like Nitroz mentioned in post #5...

This makes more sense...

With selector ring available, a full output current for XPG2 or Nichia219 at 1.5A would seem much much better, I agree... And I did joke about swapping a driver, I've seen a pic of internals of U2 and it's not just an ordinary driver inside...


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## Nitroz

Redhat703 said:


> This is a beautiful mod! It makes me want to mod mine as I have 3 U2A's. I have a question: does the Nichia 219 LED fit in?



The Nichia will fit since it can use the same board as the XPG2. Now the only thing is what the beam looks like at the 2mm like the XPG2.

Sent from my SAMSUNG-SGH-I747 using Tapatalk 2


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## Redhat703

Thanks Nitroz for your info!


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## Mikeg23

So where do you buy the emitter/board from? This looks like a pretty simple mod with lots of room to work... I've never cared for my U2 simply because of the tint and lack of flood if it had a 3,000-4,000k XPG or XPG2 is probably love it!


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## Mikeg23

I know it's an old thread but.... No one knows?


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## yoginen

I have an old Surefire KL 1 head. Can this same mod be done to the KL 1 head?


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## Nitroz

Mikeg23 said:


> I know it's an old thread but.... No one knows?



Pm sent!


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## LumensMaximus

Who wants to mod my new U2? :shrug:


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## Nitroz

LumensMaximus said:


> Who wants to mod my new U2? :shrug:



PM sent!


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## m4a1usr

This is a pretty good starter thread for those modr's who want to tackle this job. But do your homework first. There are more links you should read here on CPF and the U-tube video is a must! I got started tonight but could not get the head apart and I had everything just as in the video. Am going to build a custom fixture for the head and a notched plate for the lower section containing the hall effect sensor. Getting the control ring off just like as in the video was pretty simple. I just cant bring myself to clamp any harder on the head than I am now with vise grips.


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## Nitroz

m4a1usr said:


> This is a pretty good starter thread for those modr's who want to tackle this job. But do your homework first. There are more links you should read here on CPF and the U-tube video is a must! I got started tonight but could not get the head apart and I had everything just as in the video. Am going to build a custom fixture for the head and a notched plate for the lower section containing the hall effect sensor. Getting the control ring off just like as in the video was pretty simple. I just cant bring myself to clamp any harder on the head than I am now with vise grips.



As you see the SF lights are not easy to crack open. I don't use vice grips on the body of the light anymore after my first mod on my U2 ended up with a crushed wall. You have got to love loctite.


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## m4a1usr

Nitroz said:


> As you see the SF lights are not easy to crack open. I don't use vice grips on the body of the light anymore after my first mod on my U2 ended up with a crushed wall. You have got to love loctite.



Well I finally got mine opened today. What a PIA! Not only were you correct about the locktite I ended up having to build a custom holder for the lower section. Surefire used REAL locktite in my light. Not the typical black crud more commonly used where you can use a heat gun to soften it up. Mine has honest to gawd RED 271 PERMANENT thread locker. The kind you need to use a torch to break down. You cant soften the red stuff. Lots and lots of heat will weaken its bond but does not soften it. Luckily I did not bubble the reflector. Now I gotta decide on which LED to use? I have a bunch of XPG/XPE in all sorts of ranges. And I have some copper sinkpads on hand to boot.


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## Nitroz

I had to deal with this nasty stuff. I have never had much of a problem with any Surefire lights but as you will see by the pictures SF was way over zealous with the red loctite on this one. But, in the end, I WON!
















And here we have the cleaned up threads. Next up, XP-G2 install.


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## Nitroz

This one is done and headed back to its owner.


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## KITROBASKIN

Thanks so much for the pictures and for breathing new life into a classic, history making flashlight.


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## LumensMaximus

Hey, those photos, I've seen them before, of course.. that's my U2 . Let me say up front that I love Surefire lights, and their quality IMO, is second to none. For the record, I'm mostly a lurker if you haven't noticed, not a big poster when it comes to reviews, technical stuff, beam shots and a lot of chimming in. When I finally bought a U2 though, I have to say I was excited, another top quality torch from one of my favorite companies, 6 levels of light, clicky tail, not too much bigger in size than my 6P, man it couldn't get much better. When I fired it up and seen that horrible purplish tint, all the wind went out of my sail. I placed it in my light drawer thinking this one will be visiting Ebay soon. Then I'd seen "U2" under the modding section for an XP-G2 by Nitroz. After an email to see if he'd mod mine, Russell took my light, was super fast, did an awesome job and before I knew it, my new U2 was on the way back. This puppy is much improved, my only question is for Surefire, as to why they don't do the same? They would most likely have a large supply and demand problem. I will never sell this one now and you're contemplating the same or have any regrets for your U2 purchase, send Nitroz an email. Thanks again Russell, I'll be sending you another soon:twothumbs :twothumbs


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## m4a1usr

If it wasn't for this thread my U2 would have sat, amongst the herd of other SF lights purchased to mod, and waited its turn. Since my current U2 now has the XPG2 mod its time to look for another to do an XML2 mod. But I might have to wait for the XPL to become more available though. :devil:


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## Eric242

m4a1usr said:


> ......for another to do an XML2 mod.


That´s what I thought too when I saw the size of the reflector opening compared to the XP-G2 LED.


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## Nitroz

LumensMaximus said:


> Hey, those photos, I've seen them before, of course.. that's my U2 . Let me say up front that I love Surefire lights, and their quality IMO, is second to none. For the record, I'm mostly a lurker if you haven't noticed, not a big poster when it comes to reviews, technical stuff, beam shots and a lot of chimming in. When I finally bought a U2 though, I have to say I was excited, another top quality torch from one of my favorite companies, 6 levels of light, clicky tail, not too much bigger in size than my 6P, man it couldn't get much better. When I fired it up and seen that horrible purplish tint, all the wind went out of my sail. I placed it in my light drawer thinking this one will be visiting Ebay soon. Then I'd seen "U2" under the modding section for an XP-G2 by Nitroz. After an email to see if he'd mod mine, Russell took my light, was super fast, did an awesome job and before I knew it, my new U2 was on the way back. This puppy is much improved, my only question is for Surefire, as to why they don't do the same? They would most likely have a large supply and demand problem. I will never sell this one now and you're contemplating the same or have any regrets for your U2 purchase, send Nitroz an email. Thanks again Russell, I'll be sending you another soon:twothumbs :twothumbs



Thanks Robert!

The Surefire U2 is an excellent design that was not executed well when it came to the LED selection. Every one of the U2s that I have modded with a Seoul LED has the horrible, weak blue tint to them. I am shocked that SF would let something like this go out the door, even the old 5 watt U2 had better color to it.

And that is why we do what we do.


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## Tiresius

Curious as to whether I can mill the risers off and use an XM-L2 or MT-G2 in there. Is there a thin layer of fiberglass that is under the black coat that directs the polarities?


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## m4a1usr

Tiresius said:


> Curious as to whether I can mill the risers off and use an XM-L2 or MT-G2 in there. Is there a thin layer of fiberglass that is under the black coat that directs the polarities?



You could pull out the heat sink and mill off the raised area but its easier to use as is and turn down a copper MCPCB soldered to a short piece of .375 brass rod. The inner measurement of the recessed area where the original LED sits is .310 . There is no insulator for the LED surface mount. The 2 leads that come thru the LED heat sink do have electrical insulator pads but they are small adhesive pads and held in place with cheap what ever media. When I made my XPG2 LED MCPCB for this conversion I made my LED pad .130 OAL thickness.

I knew this was a bit too thick and the reflector would be out of focus but I also knew as well I could create a small spacer to dial in the perfect hot spot later. Turns out a larger bezel O-ring (.025 dia) allowed for perfect spacing. An XML will not have as tight throw as with the XPG but it would certainly be interesting to find out what could be. And this is a perfect tool to be experimenting with


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## cland72

Any idea what lumen output is with the XPG2 LED upgrade and stock driver? I'm regretting selling my U2...


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## Nitroz

cland72 said:


> Any idea what lumen output is with the XPG2 LED upgrade and stock driver? I'm regretting selling my U2...



I would say around 250 lumens maybe. It's a noticeable difference, not just in tint quality but the beam is much better with good hotspot to spill transition.


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## tobrien

Nitroz said:


> I would say around 250 lumens maybe. It's a noticeable difference, not just in tint quality but the beam is much better with good hotspot to spill transition.



nice! I'm regretting having sold my U2 too :/


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## Justin Case

m4a1usr said:


> You could pull out the heat sink and mill off the raised area but its easier to use as is and turn down a copper MCPCB soldered to a short piece of .375 brass rod. The inner measurement of the recessed area where the original LED sits is .310 . There is no insulator for the LED surface mount. The 2 leads that come thru the LED heat sink do have electrical insulator pads but they are small adhesive pads and held in place with cheap what ever media. When I made my XPG2 LED MCPCB for this conversion I made my LED pad .130 OAL thickness.



The inside diameter between the risers or ribs is designed to fit LEDs with 8mm cases, which is the case diameter of both the Seoul P4 and Luxeon V used in various generations of the U2.

There is an insulator for direct surface mount of an LED -- it's the black anodizing. However, in the sense of whether you'd actually depend on that anodizing, I agree that perhaps effectively there is no reliable insulating layer. But any decent layer of thermal epoxy such as Arctic Alumina will give you the desired electrical isolation. Also, note that the Seoul P4 uses a slug that is connected to the anode, and SureFire didn't use anything special to insulate the slug, other than thermal epoxy.

IIRC, I used a copper shim that is ~1.2mm thick to raise up an XM-L that is mounted on a datiLED 8mm MCPCB to the correct focus height. For an XP-G (and I assume XP-G2), I found that if the MCPCB and shim added up to 2mm thick, the LED was at the right focus height. It looks like post #32 uses an XP-G2 that is mounted on a 10mm diam MCPCB and trimmed down to 8mm diam. Those 10mm MCPCBs are already 2mm thick.


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## m4a1usr

Justin Case said:


> The inside diameter between the risers or ribs is designed to fit LEDs with 8mm cases, which is the case diameter of both the Seoul P4 and Luxeon V used in various generations of the U2.
> 
> There is an insulator for direct surface mount of an LED -- it's the black anodizing. However, in the sense of whether you'd actually depend on that anodizing, I agree that perhaps effectively there is no reliable insulating layer. But any decent layer of thermal epoxy such as Arctic Alumina will give you the desired electrical isolation. Also, note that the Seoul P4 uses a slug that is connected to the anode, and SureFire didn't use anything special to insulate the slug, other than thermal epoxy.
> 
> IIRC, I used a copper shim that is ~1.2mm thick to raise up an XM-L that is mounted on a datiLED 8mm MCPCB to the correct focus height. For an XP-G (and I assume XP-G2), I found that if the MCPCB and shim added up to 2mm thick, the LED was at the right focus height. It looks like post #32 uses an XP-G2 that is mounted on a 10mm diam MCPCB and trimmed down to 8mm diam. Those 10mm MCPCBs are already 2mm thick.



Gotta agree with you 100%. I'm going to do my next U2 mod with a copper spacer instead of a brass one. Here is my recent mod.


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## Nitroz

m4a1usr said:


> Gotta agree with you 100%. I'm going to do my next U2 mod with a copper spacer instead of a brass one. Here is my recent mod.



It is always nice to add that extra touch to a mod even if it is overkill. 

Now I just have to decide what LED I want to mod the old Lux V U2 with, decisions....decisions.


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## KITROBASKIN

Nitroz said:


> It is always nice to add that extra touch to a mod even if it is overkill.
> 
> Now I just have to decide what LED I want to mod the old Lux V U2 with, decisions....decisions.



Keep us updated... And thanks for the great work you did for me. Plus; Just loving the GITD treatment on the ITW Grimloc carabiner. It is enough glow to have a practical use. Great!


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## Nitroz

I just finished this up, I think this might be the first U2 with an XP-L and I must say I really like this LED.

First picture is the light completed, the second is the stock beamshot, and the last is the modded beamshot. The beamshot exposure for both pictures are locked and the same.


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## TexLite

This was honest to goodness one of the first hosts I thought about when I heard about Cree's new XM-L2 and XP-G2 love child, aka the XP-L. Thought I'd check out CPF after a looooong hiatus and see if anyone was using it yet, and look what my eyes do see, someone actually popped one in a U2A. Not only that, it's an "old hand" lol. 

Great work Nitroz!

Hard to tell from the pics, but are there any artifacts from the weird lines Cree is molding in the dome?


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## KITROBASKIN

So Impressive.

The work you did for me is very much appreciated.


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## Nitroz

TexLite said:


> This was honest to goodness one of the first hosts I thought about when I heard about Cree's new XM-L2 and XP-G2 love child, aka the XP-L. Thought I'd check out CPF after a looooong hiatus and see if anyone was using it yet, and look what my eyes do see, someone actually popped one in a U2A. Not only that, it's an "old hand" lol.
> 
> Great work Nitroz!
> 
> Hard to tell from the pics, but are there any artifacts from the weird lines Cree is molding in the dome?



No artifacts at all. I am not sure why the camera captured the rings in both photos but in reality those do not exist.

Being that the dome is frosted I wish Cree would make a XP-LC, the "C" notation meaning a clear dome. I wonder if that would make it throw more.


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## Kestrel

Nitroz said:


> The Surefire U2 is an excellent design that was not executed well when it came to the LED selection. Every one of the U2s that I have modded with a Seoul LED has the horrible, weak blue tint to them. I am shocked that SF would let something like this go out the door, even the old 5 watt U2 had better color to it.
> 
> And that is why we do what we do.


The thing that a lot of folks seem to miss is that (theoretically) the older LuxV U2's may be a much better mod host.
I agree that the big problem with most of the newer SSC P4's coming from SF had that bluish tint to them.
The first popular upgrade for the P4 U2A's were the neutral-tint XP-G's, however the increase in output for these mods were marginal IIRC. Perhaps 50%, if that? :thinking:

Remember when the U2A came out and it didn't promise much in the way of increased output over the LuxV U2's?
What they did deliver was ~2x the runtime at all output levels (and compatibility with common ~3v emitters being used for upgrades like the XP-G).

Edit: And therefore the wattage for the newer U2A's was decreased by half. What us flashaholics needed instead was a more efficient ~6V emitter, not the more efficient ~3v SSC P4.

Other modders were still using MC-E's in their ~6v U2's (wiring them 2s2p) and getting something like 3-4x the original output - far superior to the best upgrade option for the ~3v U2A's.
However, it appeared to me that the upgrade was rather more involved due to the complicated (albeit flexible) design of the MC-E module.
The best modders even milled out the back end of the U2 reflectors to fully seat the large MC-E to permit the best focus.

Fast-forward to now with the XM-L 6V EZW - now we have a truly modern emitter that can be effectively paired with the *(higher wattage) original U2*.
It's ironic that the older U2's may now be far superior to the U2A's due to this configuration.

This is the first good thread we've had on the U2's for a while IMO. :thumbsup:


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## m4a1usr

Kestrel said:


> The thing that a lot of folks seem to miss is that (theoretically) the older LuxV U2's may be a much better mod host.
> I agree that the big problem with most of the newer SSC P4's coming from SF had that bluish tint to them.
> The first popular upgrade for the P4 U2A's were the neutral-tint XP-G's, however the increase in output for these mods were marginal IIRC. Perhaps 50%, if that? :thinking:
> 
> Remember when the U2A came out and it didn't promise much in the way of increased output over the LuxV U2's?
> What they did deliver was ~2x the runtime at all output levels (and compatibility with common ~3v emitters being used for upgrades like the XP-G).
> 
> Other modders were still using MC-E's in their ~6v U2's (wiring them 2s2p) and getting something like 3-4x the original output - far superior to the best upgrade option for the ~3v U2A's.
> However, it appeared to me that the upgrade was rather more involved due to the complicated (albeit flexible) design of the MC-E module.
> The best modders even milled out the back end of the U2 reflectors to fully seat the large MC-E to permit the best focus.
> 
> Fast-forward to now with the XM-L 6V EZW - now we have a truly modern emitter that can be effectively paired with the *(higher wattage) original U2*.
> It's ironic that the older U2's may now be far superior to the U2A's due to this configuration.
> 
> This is the first good thread we've had on the U2's for a while IMO. :thumbsup:



I gotta agree with you there! Certainly got me moving on my accumulated herd purchased just to modify. I'm still looking for another cheap U2 for an XML conversion. Just got done with a KL4 mod using an MCE and should have done my homework a bit better since everything I now find on CPF clearly shows the MCE is a mega heat generator. Too bad it was an easy conversion. Thankfully DeFabricata (sp?) has the better solution in his build thread.


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## Nitroz

KITROBASKIN said:


> So Impressive.
> 
> The work you did for me is very much appreciated.



Thank You!


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## AndyF

I received the XP-L mod yesterday and must say it's a HUGE improvement both in output and especially in tint quality.

Highly recommended! Thanks.


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## Nitroz

AndyF said:


> I received the XP-L mod yesterday and must say it's a HUGE improvement both in output and especially in tint quality.
> 
> Highly recommended! Thanks.



Thanks! Now you can enjoy a great light the way it should have been made.


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## tobrien

man how I want a U2 again


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## Justin Case

Kestrel said:


> It's ironic that the older U2's may now be far superior to the U2A's due to this configuration.


 I think that's debatable. With the boost driver, you basically have to use 2x123A and at the Vf and If levels for the LED upgrades, you are still looking at shorter run times and lots of heat. If you want to run with rechargeables, you may have a hard time. You can't go with 2xLCO Li-ions, because Vbatt >> Vf. 1xLCO Li-ion is less than desirable because the driver can't reach full regulation. You might be ok with 2xLFP123, but the capacity of those cells is low, making a short run time even shorter and you still may have Vbatt > Vf. A U2A with an XM-L2 U2 bin LED can probably reach a datasheet estimated output of around 400 emitter lumens. Sure, an M bin 2S2P MC-E driven at 1000mA (500mA per die) probably can hit 500 emitter lumens or so. But I think it's doubtful that you'd see any meaningful real world difference in terms of lumens output. However, you might notice that the throw for the XM-L2 could be better than that for the MC-E. I would say it's almost a certainty that if you used an XP-G2 in a U2A that you'd outthrow a U2 with an MC-E.


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## Nitroz

Justin Case said:


> I think that's debatable. With the boost driver, you basically have to use 2x123A and at the Vf and If levels for the LED upgrades, you are still looking at shorter run times and lots of heat. If you want to run with rechargeables, you may have a hard time. You can't go with 2xLCO Li-ions, because Vbatt >> Vf. 1xLCO Li-ion is less than desirable because the driver can't reach full regulation. You might be ok with 2xLFP123, but the capacity of those cells is low, making a short run time even shorter and you still may have Vbatt > Vf. A U2A with an XM-L2 U2 bin LED can probably reach a datasheet estimated output of around 400 emitter lumens. Sure, an M bin 2S2P MC-E driven at 1000mA (500mA per die) probably can hit 500 emitter lumens or so. But I think it's doubtful that you'd see any meaningful real world difference in terms of lumens output. However, you might notice that the throw for the XM-L2 could be better than that for the MC-E. I would say it's almost a certainty that if you used an XP-G2 in a U2A that you'd outthrow a U2 with an MC-E.



While I agree with the battery configuration for the old U2 is not ideal my thoughts have changed since this habit started years ago. I use to love a flashlight with lots of throw and hardly any spill, and while I still have a light or two like that, I have gravitated towards a more subtle throw/spill combination being much more useful, IMO. I must be getting OLD. 

One of my favorite lights is my triple XP-G2 Arc Ls.


----------



## Justin Case

Nitroz said:


> While I agree with the battery configuration for the old U2 is not ideal my thoughts have changed since this habit started years ago. I use to love a flashlight with lots of throw and hardly any spill, and while I still have a light or two like that, I have gravitated towards a more subtle throw/spill combination being much more useful, IMO. I must be getting OLD.


 A U2 with an XM-L2 or XP-G2 has decent spill. I never said that the beam would be mostly throw and little spill. In any case, I think you've missed the point. The point is that something like a U2A with an XM-L2 or XP-G2 will have certain performance specs that undoubtedly will be very desirable for a fair number of people, such as battery flexibility, run time, and throw. So to postulate that the old U2 with boost driver is "far superior" to the buck-driven U2A seems rather overblown, given that the 3 listed areas of U2A superiority above are non-trivial specs.


----------



## Nitroz

Justin Case said:


> A U2 with an XM-L2 or XP-G2 has decent spill. I never said that the beam would be mostly throw and little spill. In any case, I think you've missed the point. The point is that something like a U2A with an XM-L2 or XP-G2 will have certain performance specs that undoubtedly will be very desirable for a fair number of people, such as battery flexibility, run time, and throw. So to postulate that the old U2 with boost driver is "far superior" to the buck-driven U2A seems rather overblown, given that the 3 listed areas of U2A superiority above are non-trivial specs.



Ok, I missed the boat on that one.


----------



## black bolt

PM sent.


----------



## Nitroz

Another XP-L U2 on its way home.


----------



## tobrien

good work Nitroz! is that XP-L low-domed? it almost looks de-domed i guess


----------



## Nitroz

tobrien said:


> good work Nitroz! is that XP-L low-domed? it almost looks de-domed i guess



Thanks! No, that still has a dome on it. The XP-L is a decent LED, IMO.


----------



## tobrien

Nitroz said:


> Thanks! No, that still has a dome on it. The XP-L is a decent LED, IMO.



got it, thank you! it looks like you do some pretty clean work!


----------



## gottawearshades

After I saw this thread, I asked Vinh Nyugen to put one of these in a Lux U2 for me (the head was already opened, btw, or else Vinh wouldn't have taken it). He didn't say exactly what he did, but the performance is incredible. It's a completely different light!

My understanding is this light has a buck circuit for three levels, and then a boost circuit for three more. It loos like the emitter is just pulling all kinds of power from the boost circuit, so I only get one level of brightness, and it is crazy bright. It looks like level one is 1 or 2 lumen, and level two is 10 or 15, and level three is at least 300 lumen. The last three levels collapse into 800 lumens?! It's a beautiful beam, throwy with plenty of spill (sorry, when I've tried to take beam shots before, Shaka when the walls fell). 

I'm concerned about running on primaries, I won't be running it on max for more than a minute or two, but I don't need to at level three is as bright as my Malkoff MDC but with more throw. 

Now my U2 is fun again.


----------



## Justin Case

gottawearshades said:


> After I saw this thread, I asked Vinh Nyugen to put one of these in a Lux U2 for me (the head was already opened, btw, or else Vinh wouldn't have taken it). He didn't say exactly what he did, but the performance is incredible. It's a completely different light!
> 
> My understanding is this light has a buck circuit for three levels, and then a boost circuit for three more. It loos like the emitter is just pulling all kinds of power from the boost circuit, so I only get one level of brightness, and it is crazy bright. It looks like level one is 1 or 2 lumen, and level two is 10 or 15, and level three is at least 300 lumen. The last three levels collapse into 800 lumens?! It's a beautiful beam, throwy with plenty of spill (sorry, when I've tried to take beam shots before, Shaka when the walls fell).
> 
> I'm concerned about running on primaries, I won't be running it on max for more than a minute or two, but I don't need to at level three is as bright as my Malkoff MDC but with more throw.
> 
> Now my U2 is fun again.


Whether it is just boost, or buck-boost, at the upper levels you aren't getting any boost driver action since Vbatt>VLED if you replaced the Lux V with an XP-G2. You are running direct drive, which is why you don't have any upper brightness levels. It's all just one level, and most likely you are seriously overdriving the LED and the driver itself. It's a testimony to the ruggedness of SureFires that the light hasn't croaked yet.


----------



## black bolt

Nitroz said:


> Another XP-L U2 on its way home.



This was my U2 host that Russ swap out the stock SSC P4 for a XPL led. I received it back several days ago and have been using since then daily. I bought this U2 about a year and half months ago on Craigslist for $50 bnib and not even at that price, could have made me use that ugly blueish/purple tint led everyday. It sat on the shelf from there on until I saw this thread on the U2 led mod and said to myself "Why not, I got a hell of a deal on the flashlight, so whats another $65 to see if it could make me love this light?" Russ, you did a fine job on the mod and WOW what a huge difference the new led makes. The XPL led was made for this flashlight because it throws more and has a lot more spills then the stock ever did. I even love the tint that the led is putting out, much warmer then my Malkoff M61W dropin. Thanks for everything Russ and if I ever pickup another U2 flashlight, it definitely will be heading off to your location.


----------



## gottawearshades

<irony>
Yes, but did you catch the part where I said it is very bright?
</irony>



Justin Case said:


> Whether it is just boost, or buck-boost, at the upper levels you aren't getting any boost driver action since Vbatt>VLED if you replaced the Lux V with an XP-G2. You are running direct drive, which is why you don't have any upper brightness levels. It's all just one level, and most likely you are seriously overdriving the LED and the driver itself. It's a testimony to the ruggedness of SureFires that the light hasn't croaked yet.


----------



## Nitroz

black bolt said:


> This was my U2 host that Russ swap out the stock SSC P4 for a XPL led. I received it back several days ago and have been using since then daily. I bought this U2 about a year and half months ago on Craigslist for $50 bnib and not even at that price, could have made me use that ugly blueish/purple tint led everyday. It sat on the shelf from there on until I saw this thread on the U2 led mod and said to myself "Why not, I got a hell of a deal on the flashlight, so whats another $65 to see if it could make me love this light?" Russ, you did a fine job on the mod and WOW what a huge difference the new led makes. The XPL led was made for this flashlight because it throws more and has a lot more spills then the stock ever did. I even love the tint that the led is putting out, much warmer then my Malkoff M61W dropin. Thanks for everything Russ and if I ever pickup another U2 flashlight, it definitely will be heading off to your location.



Thanks! It definitely makes the U2 a user.

If you ever have any problems with your light I will fix it.


----------



## black bolt

Nitroz said:


> Thanks! It definitely makes the U2 a user.
> 
> If you ever have any problems with your light I will fix it.



Will do Russ and thanks again! :twothumbs


----------



## yubes88

Hey guys I'm looking to mod my light as well. I was issued this light in Iraq in 2008. I love it and still use it everyday from searching large open areas to reading in the tent. I know it can be so much better, so here are a few pics, let me know what my options are.


----------



## m4a1usr

Looks like you have done the hardest part of a U2 conversion. That is opening up the bezel. Few bother with messing with the driver since the UI is very practical. Now just make the decision on which LED you may want. The XPG2 is a well known choice or maybe an XML or XPL? Both good choices but do not expect the same throw compared to the XPG2. I know. Decisions, decisions.


----------



## yubes88

m4a1usr said:


> Looks like you have done the hardest part of a U2 conversion. That is opening up the bezel. Few bother with messing with the driver since the UI is very practical. Now just make the decision on which LED you may want. The XPG2 is a well known choice or maybe an XML or XPL? Both good choices but do not expect the same throw compared to the XPG2. I know. Decisions, decisions.



so are you saying the XP-G2 will throw the best? I like what little I've seen of the XP-L so far but don't know enough to make an informed decision.


----------



## tobrien

yubes88 said:


> Hey guys I'm looking to mod my light as well. I was issued this light in Iraq in 2008. I love it and still use it everyday from searching large open areas to reading in the tent. I know it can be so much better, so here are a few pics, let me know what my options are.
> [IM]http://i111.photobucket.com/albums/n138/yubes88/IMG_20140817_083425_042_zps2fe76fd9.jpg[/IMG]
> [IG]http://i111.photobucket.com/albums/n138/yubes88/IMG_20140817_083434_727_zpsb5925c3d.jpg[/IMG]
> [MG]http://i111.photobucket.com/albums/n138/yubes88/IMG_20140817_083506_589_zpse6356d12.jpg[/IMG]
> [IM]http://i111.photobucket.com/albums/n138/yubes88/IMG_20140817_080622_890_zpse1973e58.jpg[/IMG]
> [IG]http://i111.photobucket.com/albums/n138/yubes88/IMG_20140817_081001_751_zps0989ad76.jpg[/IMG]
> [IG]http://i111.photobucket.com/albums/n138/yubes88/IMG_20140817_081310_426_zps89beb5da.jpg[/IMG]


first: thank you for serving our great country!

second: worst case scenario you're unable to do it yourself, there are plenty of guys on this forum who can do it for you for pretty little cash


----------



## yubes88

tobrien said:


> first: thank you for serving our great country!



Thanks for your support, 

So is this upgrade as simple as unmounting and re-soldering the new led? If so, I should be able to handle that. Otherwise I'd love to find someone who is willing to help me out.


----------



## Nitroz

yubes88 said:


> Thanks for your support,
> 
> So is this upgrade as simple as unmounting and re-soldering the new led? If so, I should be able to handle that. Otherwise I'd love to find someone who is willing to help me out.



PM sent!


----------



## yubes88

Nitroz said:


> PM sent!



My lights on its way to Nitroz! I can't wait to see some build pics and especially those before and after beam shots!


----------



## KITROBASKIN

yubes88 said:


> My lights on its way to Nitroz! I can't wait to see some build pics and especially those before and after beam shots!



Good Call!
His work has been very nice. He recently returned a Sportac dropin with upgraded wire, multi mode driver, and triple DEDOMED XPL emitters. One amp to each LED on 100% with a bonafide moonlight. My wife really likes the warm tint and the very broad yet powerful hotspot. It has become our ambient light in the bedroom and her field torch. It is never too hot to hold but will use-the-juice if left on full speed extensively, as would be expected. I plan on doing a short video on it, after more real time use.


----------



## EzGoingKev

Does anyone know if the XM07 tailcap switch works on this?


----------



## m4a1usr

EzGoingKev said:


> Does anyone know if the XM07 tailcap switch works on this?



Don't see why it wouldn't? It will certainly screw on and should work fine. Could try it tonight when I get home and see how well it works.


----------



## JBA

PM sent.


----------



## precisionworks

Will the U2-XPL see the same drive current & voltage running 1x18650 as it does running 2xCR123?


----------



## Nitroz

precisionworks said:


> Will the U2-XPL see the same drive current & voltage running 1x18650 as it does running 2xCR123?


You know I am not sure, but I am curious about that myself.

Next time I have one I am going to check that out.

The XP-L might see a little more current than the Seoul p4 due to the lower VF.


----------



## JBA

So I received my U2 back from *Nitroz* after a twelve day turnaround. All I can say is that I'm very impressed with how the light has been transformed. The low level is lower now and IMO more useful for things like reading in the dark or looking in a backpack without being to overpowering. I find myself using the intermediary levels more now than I did before and the high level is really blinding. I wish I had taken pics of the before beamshot but it is a big difference. I have a long driveway and I typically use the flashlight to shine at my gate to make sure it's closed and to give me an idea of how far the throw is on the light. I can now see a little into the woods across the street from my gate although it's harder to tell now that they've fixed the street light. 

This is my second U2 that I have purchased after losing my first one early last year on a camping trip. Between upgrading the emitter and getting the light bored for an 18650 from *precisionworks*, this is by far the most useful light I have ever owned and it's a keeper. I've probably got $240 invested in this light with those two modes and what I paid for the light but it's worth it. I'm sure other's can point to lights that are cheaper and/or brighter but I have yet to find one with the six levels of brightness along with Surefire's built like a brick toughness and quality. Thanks Russ for the great job and quick turnaround!


----------



## Nitroz

JBA said:


> So I received my U2 back from *Nitroz* after a twelve day turnaround. All I can say is that I'm very impressed with how the light has been transformed. The low level is lower now and IMO more useful for things like reading in the dark or looking in a backpack without being to overpowering. I find myself using the intermediary levels more now than I did before and the high level is really blinding. I wish I had taken pics of the before beamshot but it is a big difference. I have a long driveway and I typically use the flashlight to shine at my gate to make sure it's closed and to give me an idea of how far the throw is on the light. I can now see a little into the woods across the street from my gate although it's harder to tell now that they've fixed the street light.
> 
> This is my second U2 that I have purchased after losing my first one early last year on a camping trip. Between upgrading the emitter and getting the light bored for an 18650 from *precisionworks*, this is by far the most useful light I have ever owned and it's a keeper. I've probably got $240 invested in this light with those two modes and what I paid for the light but it's worth it. I'm sure other's can point to lights that are cheaper and/or brighter but I have yet to find one with the six levels of brightness along with Surefire's built like a brick toughness and quality. Thanks Russ for the great job and quick turnaround!



Thanks JBA!

I wish I could say that all of my mods are a quick turnaround and as flawlessly executed but sometimes that is not always the case. I will do what it takes to keep anyone satisfied with the outcome.

My motto, the customer always comes first!


----------



## Justin Case

m4a1usr said:


> Looks like you have done the hardest part of a U2 conversion. That is opening up the bezel. Few bother with messing with the driver since the UI is very practical. Now just make the decision on which LED you may want. The XPG2 is a well known choice or maybe an XML or XPL? Both good choices but do not expect the same throw compared to the XPG2. I know. Decisions, decisions.



A little late in responding to this. The photos from yubes88 clearly show a Luxeon V emitter, which means his U2 is an older one that uses a boost driver and an LED with a Vf in the 6V range. Replacing a Lux V with an XP-G2, which will have a Vf in the <3V range is a poor choice if you plan to use 2 x 123A or 2 x Li-ion since Vbatt > Vf and thus the driver is no longer in boost mode. Now maybe you could run the light on 1x17670 or 1x18650. But I think you'll still be in direct drive mode (just not severely overdriven) and thus won't have the lower output levels available via the selector ring.


----------



## Justin Case

precisionworks said:


> Will the U2-XPL see the same drive current & voltage running 1x18650 as it does running 2xCR123?



Addressing the Seoul version of the U2, you might see a difference in the drive current at the high setting on the selector ring. It depends on how much parasitic resistance, and thus voltage drop, your light has, plus how much voltage overhead the SureFire driver needs to reach full regulation. If the light is clean and has little drop, the driver's voltage overhead is minimal, and you have a top-performing 18650 that can hold a high voltage under load, then 1xLi-ion probably can reach full regulation and maybe stay there for some of the battery's run time.

If the light can reach full regulation for 1x18650, then you won't see any drive current difference vs 2x123A since the driver is a constant current regulator. If the light doesn't reach full regulation with 1x18650 (or the light eventually falls out of full regulation), then you will see a drive current difference since the 1x18650 case can't deliver the goods and thus you get lower drive current.

I vaguely recall that when I tested some old XP-Gs in a U2A running 1xLi-ion, the light didn't reach full regulation. I forget what I measured for the voltage overhead to reach full regulation, but 0.5V or more is quite common. The shortcoming was that LED Vf was not low enough. As I recall, the LEDs were in the 3.1V range.

The U2A drive current is around 900+ mA, so an XP-L Vf could be around 2.9V. Add 0.5V overhead, and you need a Vbatt of at least 3.4V. If you have say 100 milliohm of parasitic resistance, that adds another 0.29V. So Vbatt now has to be at least ~3.7V.

So I'd say that 1x18650 can reach full regulation, and hold it for a reasonable amount of the total run time.

Certainly, 2x123A has plenty of voltage to reach and stay in full regulation.


----------



## precisionworks

Great explanation Justin Case, thanks.


----------



## novice

I have several U2 lights (the Seoul P4 version). Fortunately, one of the used ones I got has a bezel that easily unscrews by hand (someone has probably already opened it up). One of my U2 bodies is bored for 18650. I am an electronics bantamweight. How difficult would it be to do a build using either an XP-G2 or warm MC-E that would run off of either 2xCR123a _or_ 2x AW protected 18650 cells, using a Fivemega extension tube?


----------



## Funny monkey 7

Hello everyone! Newbie here. I wanted to know where I could get an led to mod my U2 with? I found some online but they seem to big to fit in the U2 head.


----------



## Greenbean

Just want to jump in here and double check this LED in my newly acquired U2,

This is the Soul P4 correct? The tint is good. I like it...

Just want to be sure as down the road I may want to send it to someone to mod and get an XP-L or XM-L2...
Which of the two mentioned LEDs would give me the best use of the 6-modes?


----------



## Icarus

You're right, this is a Seoul P4. Not sure which LED would be best in the U2 reflector. It also depends what you are after. In general the XP-L throws better than the XM-L2.


----------



## Greenbean

Hmm, Not to concerned with throw but if one offered more flood and yet still had the real low low mode, that would be my pick.


----------



## m4a1usr

Man am I glad someone brought this thread back to life. Reminded me to get off my you know what and finish off the last couple of lights I have set aside. Planned on doing XML EZ whites but reading this now has me thinking maybe an XHP50 just might fit? The opening in the U2 reflector does look big enough to fit.


----------



## Greenbean

Your welcome! Lol... :twothumbs

So what needs to be considered in keeping the 6 factory settings of output when choosing a new LED?
The low mode is fantastic for me, I wouldn't want to lose that. I like the 6 different levels as it ramps up or down.


----------



## Icarus

If you are going to replace the Seoul by a newer emitter every level will be brighter than before unless you modify the electronics. I don't think this has been done before. Might be that low is still low enough. If you try it let us know.


----------



## Icarus

m4a1usr said:


> Man am I glad someone brought this thread back to life. Reminded me to get off my you know what and finish off the last couple of lights I have set aside. Planned on doing XML EZ whites but reading this now has me thinking maybe an XHP50 just might fit? The opening in the U2 reflector does look big enough to fit.



In case you want an XHP50 you need a U2 with LuxV emitter.


----------



## Greenbean

Icarus said:


> If you are going to replace the Seoul by a newer emitter every level will be brighter than before unless you modify the electronics. I don't think this has been done before. Might be that low is still low enough. If you try it let us know.



10-4, Honestly I'll probably leave it a while...translated year or so. 

I'm on an M6 kick lately and need to get my Incan fix first...


----------



## m4a1usr

Icarus said:


> In case you want an XHP50 you need a U2 with LuxV emitter.



Yep,..Thats the last 2 I have left for modd'n. I began these projects with a few which had the Seoul and made one with an XPG, another with an XML and the last with a XPL. The XML is probably my favorite. The deep reflector and the XML is a decent balance. The XPL is not bad but without a doubt leans to thrower. And the XPG is just plain narrow all the way. Some spill but tight hot spot.

I think the XHP50 might be most if not all spill with some hot spot. Just to be sure I will de dome one in the same color and tint so I can have a plan "B" should the obvious not be so obvious to me at this point in planning.


----------



## precisionworks

I have a U2 Ultra that I bored for 18650 & that seems like a perfect host for the XHP-50. What do you think? Please pm with price, preferred payment method & shipping address.

I don't need huge output, 1000 lm at the led is fine. I think I'd like to leave the dome on.

Just found our emails from one year ago  Is price the same as it was then for the XPL swap? I certainly understand if it has changed.


----------



## Minimoog

I have had a Luxeon U2 from when they were first released (the head was not bonded on - designed to take the 18650). What is a good LED option for the boost driver? I'd love to have mine updated!


----------



## Greenbean

precisionworks said:


> I have a U2 Ultra that I bored for 18650



I have some light bodies coming your way eventually and one is going to be my U2, lol...

XHP-50 would be awesome especially if your able to keep a low low in the first lowest setting.


----------



## precisionworks

I volunteer my U2 as a "crash test dummy". The XHP-50 has to be better than what I have now. I'm not as much concerned about the low but I would like more on the high end.


----------



## Nitroz

precisionworks said:


> I volunteer my U2 as a "crash test dummy". The XHP-50 has to be better than what I have now. I'm not as much concerned about the low but I would like more on the high end.



Email sent!


----------



## Kestrel

I had my older (~6v LuxV) U2 upgraded with a XML-EZW and it went from being one of least favorite lights ('A' for design/build, but 'D' for obsolescence) to a favorite. I normally refrain from citing specific services in the forums, but Nitroz did mine and it worked out perfectly - and keep in mind that these are one of the more difficult SF's to mod. For anyone on the fence, upgrading these fine lights are very much worth the time & effort.


----------



## Nitroz

Kestrel said:


> I had my older (~6v LuxV) U2 upgraded with a XML-EZW and it went from being one of least favorite lights ('A' for design/build, but 'D' for obsolescence) to a favorite. I normally refrain from citing specific services in the forums, but Nitroz did mine and it worked out perfectly - and keep in mind that these are one of the more difficult SF's to mod. For anyone on the fence, upgrading these fine lights are very much worth the time & effort.



Thanks Kestrel!

Yes, the U2 is a test of nerves! No one U2 is sealed the same, and some are downright Fort Knox.

I have has a few of these mods not work out for one reason or another which is stressful when dealing with such an expensive light.


----------



## AndyF

Can this mod be done with an Osram hyper red emitter?.


----------



## Nitroz

AndyF said:


> Can this mod be done with an Osram hyper red emitter?.



As long as you use a newer U2 with the Seoul LED I don't see why not.


----------



## AndyF

PM sent.


----------



## wensynch

Nitroz:

May I get a pm as well if you will offer your services upgrading another U2, the newer one (the B ones).

I love this light but don't find much use for it since it's outdated, but it'd be a dream to have it brought current. A thrower U2 sounds awesome to me. Thanks.


----------



## blue_devil_man

I recently traded for a U2 and was wondering if I could get someone to mod it for me please. These things look awesome after the upgrades.


----------



## Nitroz

blue_devil_man said:


> I recently traded for a U2 and was wondering if I could get someone to mod it for me please. These things look awesome after the upgrades.



I can do it. I would send you a PM but I think you have to have a few post under your belt before I can send you one.

Russ


----------



## blue_devil_man

Oh wow ok I sent you one last night.


----------



## Nitroz

blue_devil_man said:


> Oh wow ok I sent you one last night.



Odd, I don't see a PM from you? 

And your profile does not have a link for me to PM you.


----------



## InternalCombustion

Nitroz, 

Obvious noob here, at least to this forum. I am however a serious lumen-holic, and in my Surefire collection is a prized but humble U2. Research suggests to me that is an early model, I believe the  v1, Philips Luxeon V LED w/ Boost circuit. 

Anyway, I read this thread maybe a year ago and have been lusting for the XP-L mod, or whatever you may recommend is the latest and greatest. 

Please give me a PM. 

Many thanks. 
IC


----------



## Nitroz

InternalCombustion said:


> Nitroz,
> 
> Obvious noob here, at least to this forum. I am however a serious lumen-holic, and in my Surefire collection is a prized but humble U2. Research suggests to me that is an early model, I believe the  v1, Philips Luxeon V LED w/ Boost circuit.
> 
> Anyway, I read this thread maybe a year ago and have been lusting for the XP-L mod, or whatever you may recommend is the latest and greatest.
> 
> Please give me a PM.
> 
> Many thanks.
> IC



Hi,
I am not able to send you a PM until you have a few more post. I would be glad to do this for you.
Thanks!


----------



## InternalCombustion

Nitroz said:


> Hi,
> I am not able to send you a PM until you have a few more post. I would be glad to do this for you.
> Thanks!



No worries. My v1/Luxeon U2 represents too much technology and design excellence, to not give it a proper upgrade. Before I saved my nickels and dimes to buy it new, way back when, I lusted for that light something terrible. It and my E1B Backup are the two most estheticly pleasing lights I own. 

I will get my posts up to speed so you can PM me with the necessary details. 

Thanks again. 
IC


----------



## InternalCombustion

Nitroz, Ok so on your "Surefire mods" thread you talk about putting an XPH50 into a U2. However in this thread it seems the consensus for best U2 upgrade with current solid state technology is to use the XP-L. My main intent is to put emphasis on throw. Like decent illumination to maybe 100 yards. I have other lights for close-in spill (like my PD22UE). 

So what's the consensus for a v1/Luxeon U2, for heavy-throw performance? And I have no problem with high Kelvin temps. My background in industrial SSL luminaries has proven (at least to me) that higher Kelvin (6000-6500) generally yields better color rendering and target recognition. Yeah that depends on the chip's rated CRI, but generally in my experience 6000-6500 is ideal. But I digress. What would be the ideal mod for a v1 U2, for maximum lumen (and still variable) and max throw?

And what would the ideal battery be for that config?

Thanks for everyone's patience with all my questions. 

I'm really sorry I only recently found CPF. This forum is just crazy good. 

IC


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## GusManB

I have just picked up a U2, it's the Porcupine version and would vary much like to have it modified with somthing like am XML2 or MT-G2. Maintaining the same Reflector and the 6 setting selector would be great if possible, I have PMD you Nitroz.


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## Greenbean

GusManB said:


> Porcupine version.



Show Off! You need to post pics to back up a comment like that! Lol...

Kidding of course, but would love to see it! 

Congrats!


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## m4a1usr

GusManB said:


> I have just picked up a U2, it's the Porcupine version and would vary much like to have it modified with somthing like am XML2 or MT-G2. Maintaining the same Reflector and the 6 setting selector would be great if possible, I have PMD you Nitroz.



Is it the PK version? I hope you know you would destroy the value on it if you modified it. I mean it is yours to do whatever with but............?


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## GusManB

I will post a pic, it's in transit ATM


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## Kestrel

InternalCombustion said:


> Nitroz, Ok so on your "Surefire mods" thread you talk about putting an XPH50 into a U2. However in this thread it seems the consensus for best U2 upgrade with current solid state technology is to use the XP-L. [...]


That's because the ~6v XHP would upgrade the first-gen ~6v LuxV while the ~3v XPL would upgrade the second-generation ~3v SSC P4.


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## InternalCombustion

Kestrel said:


> That's because the ~6v XHP would upgrade the first-gen ~6v LuxV while the ~3v XPL would upgrade the second-generation ~3v SSC P4.



Ahhh. Makes sense. Thanks!


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## GusManB

Just Got the Porcupine in the Mail, the seller did say it was in new condition, and to my Surprise it was still sealed in plastic, and came with Batteries. Here are some pics, will need to try take a better one of the LED. Can any one tell what version of the LED it is?


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## Nitroz

GusManB said:


> Just Got the Porcupine in the Mail, the seller did say it was in new condition, and to my Surprise it was still sealed in plastic, and came with Batteries. Here are some pics, will need to try take a better one of the LED. Can any one tell what version of the LED it is?




That is the 5 watt Luxeon V.


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## lucca brassi

> That is the 5 watt Luxeon V.


 real relic


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## Greenbean

Nice man! Real Nice!


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## GusManB

It's a Vary interesting Light, nothing else I have handled is like it, the Tac Bezel make it looks Sleek. This is my only light with this Mag ring selector, a nice addition.


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## MIG79

Soo much information on here! I have a U2 in need of an update. Time to read through this thread.


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## Nitroz

MIG79 said:


> Soo much information on here! I have a U2 in need of an update. Time to read through this thread.



If you have any questions just PM me.
Russ


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## Greenbean

PM sent as it's finally time to get my U2 updated.


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## Lumen83

I know this is an old thread, but I would love to have my U2 modded if it would be possible. Thanks!


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## Nitroz

Two U2s going back home. One Lux V got the XPH50.2 treatment and the other received a XP-G2.

Other add on was bored a body to take 18650 batteries and added glow to the SF buttons.
















Bored body on the right




















Nice smooth beam from the XPH50.2 with no donut hole. Underexposed shot


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## Lumen83

Nitroz said:


> Two U2s going back home. One Lux V got the XPH50.2 treatment and the other received a XP-G2.
> 
> Other add on was bored a body to take 18650 batteries and added glow to the SF buttons.



I just received these and I could not be happier. You do great work and these lights are completely transformed. The tint and beam profiles on both are exactly what I want out of a light. And, each one is different. The XP-G2 has a tighter beam and is more of a thrower. The XP50.2 is more floody and really seems to light up a huge area very nicely. This light is such a good platform and now it has the beam, tint, and brightness it deservers. Thanks again. Great job.


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## Nitroz

Lumen83 said:


> I just received these and I could not be happier. You do great work and these lights are completely transformed. The tint and beam profiles on both are exactly what I want out of a light. And, each one is different. The XP-G2 has a tighter beam and is more of a thrower. The XP50.2 is more floody and really seems to light up a huge area very nicely. This light is such a good platform and now it has the beam, tint, and brightness it deservers. Thanks again. Great job.



I am glad you like them and I am sure you will find them much more useful now.

Thanks!


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## AndyF

Would an Osram Hyper Red be compatible?


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## Nitroz

AndyF said:


> Would an Osram Hyper Red be compatible?



With the U2 that uses a Seoul P4, yes.


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## josiahg52

I have more than a couple U2 lights and I'm surely going to have modify a few of them. In the meantime, I have a U2 with a broken lens that I'd like to repair.

I purchased a used U2 head consisting of a good lens, the reflector, and anodized bezel and lower head. I was hoping to remove the same from my U2 and install the door head and restore my U2. Unfortunately, the donor head is in a little worse condition than I thought. It looks like some moisture got in the donor light at some point and left residue behind.

That leaves me with two choices:


1) Complete disassembly of both heads and install the unbroken lens in my light.


2) Attempt to clean the donor head in situ and go with my original plan.


I thought of using an ultrasonic cleaner to shake loose the residue but decided against. I'm considering using warm distilled water bath to dissolve the residue back into solution and then rinse it with generous amounts of distilled water. I do have 100% technical isopropyl alcohol. I'm afraid that any liquid I use may come in contact with lubricant or sealer used during assembly, however, and make it worse. Does anyone have any other opinions or ideas for cleaning the inside of the lens and reflector? I know the general consensus is "don't". 



I'm ready to accept that neither cleaning plan above will work so I need to gather more information on disassembly. Is the bezel ring of the U2 threaded on like the rest of the body? Will a heat gun or hot water loosen the bonding material and allows it to be unthreaded?


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## Nitroz

josiahg52 said:


> I have more than a couple U2 lights and I'm surely going to have modify a few of them. In the meantime, I have a U2 with a broken lens that I'd like to repair.
> 
> I purchased a used U2 head consisting of a good lens, the reflector, and anodized bezel and lower head. I was hoping to remove the same from my U2 and install the door head and restore my U2. Unfortunately, the donor head is in a little worse condition than I thought. It looks like some moisture got in the donor light at some point and left residue behind.
> 
> That leaves me with two choices:
> 
> 
> 1) Complete disassembly of both heads and install the unbroken lens in my light.
> 
> 
> 2) Attempt to clean the donor head in situ and go with my original plan.
> 
> 
> I thought of using an ultrasonic cleaner to shake loose the residue but decided against. I'm considering using warm distilled water bath to dissolve the residue back into solution and then rinse it with generous amounts of distilled water. I do have 100% technical isopropyl alcohol. I'm afraid that any liquid I use may come in contact with lubricant or sealer used during assembly, however, and make it worse. Does anyone have any other opinions or ideas for cleaning the inside of the lens and reflector? I know the general consensus is "don't".
> 
> 
> 
> I'm ready to accept that neither cleaning plan above will work so I need to gather more information on disassembly. Is the bezel ring of the U2 threaded on like the rest of the body? Will a heat gun or hot water loosen the bonding material and allows it to be unthreaded?



The easiest thing to do is open the top part of the U2 head a swap the lens over to your old head. This will most likely require some amount of heat and a strap wrench. Disassembly of the two heads could be much more of a challenge and require a lot of heat and two strap wrenches.

Red loctite is tough stuff and requires 500 degrees F to start it to break down.


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## A1ex

Nitroz said:


> With the U2 that uses a Seoul P4, yes.


Would you be interested in modding a U2 for me?


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## turbodog

A1ex said:


> Would you be interested in modding a U2 for me?


PM would be a quicker way to reach that user probably.

welcome to cpf


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## A1ex

turbodog said:


> PM would be a quicker way to reach that user probably.
> 
> welcome to cpf


Ok thanks!


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## turbodog

That said... I'm sure there are modders here for the U2. Ask around... some are good/prompt and others not so much.

If you find a good one, let me know. I've got 2 U2's... would like to get the older one souped up a bit.


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## loydski29

I don’t think Nitroz is currently doing any modding. I wish he was though I have two U2’s I’d love him to work his magic on.


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## nbp

Correct. Nitroz isn’t taking requests right now unfortunately. I just had Vinh do an emitter swap in my U2 though and he did a wonderful job!


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## Lumen83

Nitroz did an amazing job on two U2's for me. Wish he was still modding. Unfortunately I dropped one of them just right and shattered the lens. I really wish I could find one for it but they're nowhere to be found. flashlightlens.com can't make it for me either. If anyone has U2 parts or has any idea where I can get a lens for it, please let me know. I'd hate to see this Nitroz gem never get used again.


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## turbodog

Lumen83 said:


> Nitroz did an amazing job on two U2's for me. Wish he was still modding. Unfortunately I dropped one of them just right and shattered the lens. I really wish I could find one for it but they're nowhere to be found. flashlightlens.com can't make it for me either. If anyone has U2 parts or has any idea where I can get a lens for it, please let me know. I'd hate to see this Nitroz gem never get used again.


Set an ebay alert. Might be able to grab a broken one (light, not lens).


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## turbodog

matter of fact: checkout this auction

i think i see a u2 head in the pile, bottom right area









Large Lot of Surefire Flashlight Parts AS IS- FOR PARTS 1-3 | eBay


<body><p>Large Lot of SurefirE Flashlight Parts AS IS- FOR PARTS 1-3. </p><br /><p>No idea what model these parts are for. Dirty and broken. </p><br /><p>SOLD AS IS FOR PARTS OR REPAIR ONLY. NO RETURNS FOR ANY REASON </p></body>



www.ebay.com





Looks like a u2 head in bottom right and selector ring in upper left.


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