Surefire U2 Ultra XP-G2 mod

[Nitroz]

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.

 

[tobrien]

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 :/

 

[Justin Case]

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.

 

[m4a1usr]

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.

 

[Nitroz]

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.

 

[KITROBASKIN]

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!

 

[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.

 

[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?

 

[KITROBASKIN]

So Impressive.

The work you did for me is very much appreciated.

 

[Nitroz]

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.

 

[Kestrel]

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:

 

[m4a1usr]

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.

 

[Nitroz]

So Impressive.

The work you did for me is very much appreciated.

Thank You!

 

[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.

 

[Nitroz]

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.

 

[tobrien]

man how I want a U2 again

 

[Justin Case]

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.

 

[Nitroz]

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]

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]

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.