XP-G maximum drive current?

[mfrey]

I'm getting ready to buy an S.O.B. converter from the Shoppe for a Surefire E2DL mod.

I know the data sheet cites 1A as the max drive current for the XP-G, but I was thinking of overdriving it somewhere in the neighborhood of 1200 mA. I want to make sure that the emitter can handle the excess current at least in limited bursts.

Now that some have experience modding with these new emitters, can anyone offer any insight?

Sorry if this has been definitively covered elsewhere...

 

[olrac]

I'm getting ready to buy an S.O.B. converter from the Shoppe for a Surefire E2DL mod.

I know the data sheet cites 1A as the max drive current for the XP-G, but I was thinking of overdriving it somewhere in the neighborhood of 1200 mA. I want to make sure that the emitter can handle the excess current at least in limited bursts.

Now that some have experience modding with these new emitters, can anyone offer any incite?

Sorry if this has been definitively covered elsewhere...

I have one in Sgt Burkett I'm pushing at 1.4A with out ill effects.

http://www.candlepowerforums.com/vb/showthread.php?t=246402

 

[Justin Case]

I've driven an XP-G R4 with a single-mode 3xAMC7135 driver (measured drive current of 1090mA) for an hour continuous to test output stability in an LED Turbo Tower (SF KT1 head and SF 6P host). No issues with tint shift and the tower ran cool the whole time.

I've also built a similar tower except using an SOB1227 (actual drive current measured at 1196mA). That also seems to run well.

I didn't put a thermocouple to either setup, but based on perceived hotness and from thermocouple measurements I've made before on other towers, I'd say that my XP-G towers are running at a junction temp under 80C, comparable to the heat generation from an SSC P4-based Turbo Tower. At that temp, I doubt there will be any issues with long-term lumens maintenance or tint shift.

Note, however, that driving any high powered LED at any appreciable forward current requires adequate heat sinking. It's not just when you are overdriving the LED. If I didn't heat sink the XP-G, I could easily cook it by driving it under the datasheet max spec of 1000mA.

 

[AlexGT]

The XP-G R4 I put on my Jetbeam Jet-II IBS gets hot when driven at full power (1.2A to the led) but it is absolutely blinding! No noticeable tint shift.

AlexGT

 

[JamisonM]

How about this? An R4 paired with one of H22A's P7 heatsinks and a hipCC? How long do you think the poor emitter would last?

 

[Justin Case]

With the right heat sinking, it looks like the XP-G might handle the hipCC. See this.

 

[JamisonM]

With the right heat sinking, it looks like the XP-G might handle the hipCC. See this.

That's where I got the idea. Looking at the chart again, I may drive it at a more conservative level. 1200mA and 1300mA look good and will still produce a lot of light. I think that might be the sweet spot for driving an XP-G. Looks like I'm in the market for an SOB1200.

 

[jasonck08]

Where did you guys buy your XP-G's. The only place I can find them is in the MP, from the reseller from Austrlia. And shipping is a killer at $12 for airmail.

 

[Justin Case]

Try nailbender in CPF's Custom & Mod Buy Sell Trade forum.

 

[JamisonM]

Try nailbender in CPF's Custom & Mod Buy Sell Trade forum.

Yep, that's who I've gotten all mine from.

 

[wechnivag]

Going from chip area, the XR-E had a 1mm square chip, which can handle 1A easily. The XP-G with its larger chip, i'm guessing at least 2.25mm square (1.5mmx1.5mm) can then theoratically handle 2.25 amps without being much higher loaded than the XR-E? This is with good heatsinking of course.

 

[kz1000s1]

Has anyone run one direct drive from an 18650 or RCR123?
What amperage did you get?

 

[Nake]

Has anyone run one direct drive from an 18650 or RCR123?
What amperage did you get?

I put an R5 on a 20mm board in a Nuwai big QIII using direct drive.

17670...4.05V.....2.51A
RCR123....4.09V....1.64A
IMR123....4.09V.....2.24A

 

[Nereus]

Has anyone run one direct drive from an 18650 or RCR123?
What amperage did you get?

I have direct driven a well-heatsinked XP-G (R5-bin) from a Powerizer RCR123 for a minute or two without any problems. My dmm says that input current is some 2,5-2,7 amps, meaning massive overdrive. The led is incredibly bright like this...

-N

 

[kz1000s1]

Did you run it on the bench or in a light? I have one more XP-G that I was thinking of putting in a 2C Mag running DD on an 18650 to see if you can get it to throw.

 

[jasonck08]

There is a chart that someone made showing XP-G efficiency at different currents. I believe they tested the XPG up to about 2A. Once you get that high though there is no difference in output between like 1.6A and 2A. Around 1.4A seems like the sweet spot for high output and efficiency.

I plan to make an aspherical 3D mag with an XP-G driven at 1.4A. Should be putting out ~400 lumens!

 

[Linger]

direct drive off an 18650 is fine for an r5. the efficiency at keeping down the heat is remarkable. I don't have longevity estimates for this, but why would R5 be any different from xr-e R2's, xp-e's, etc...they make do with direct drive alright.

I've put this PWM controller in a D26 drop-in:
http://www.kaidomain.com/ProductDetails.aspx?ProductId=1845
Despite old4750's claim that it puts 800ma out, Nailbender and I were talking that this board will modulate the power down for the lower modes, but 'high' is full open. You can see beamshots I put up with this driver +r5 in head to head shots with a direct drive P7, an head to head with an MG PLI (mc-e @2500ma) and the xp-g gives the multi-die emitters a solid run.

 

[Linger]

There is a chart that someone made showing XP-G efficiency at different currents.

jtr's White Led Testing is what you mean.

Yup, you're correct, the highest efficiency comes early but up to ~1500ma its still decent output.
I'm putting a few multi R4's and R5's together. My first will set of R4's will be at 1250ma (brightness vs. run-time compromise)

 

[Nereus]

Did you run it on the bench or in a light? I have one more XP-G that I was thinking of putting in a 2C Mag running DD on an 18650 to see if you can get it to throw.

I did the 2,5 - 2,7 amp direct drive test on the bench.

- N

 

[JamisonM]

Well, I did a rough build this week. It consisted of one of litemania's P7 heatsinks with an R4 XP-G on a 10mm board and mounted with arctic alumina. A hipCC was mounted on a copper plate, secured with two small screws and the plate mounted on the bottom of the heatsink with arctic alumina. I plan on doing a SST-50 build like this with the same 4D host. Anyway, sufice to say, it didn't work even though it did. The LED started to smoke, literally. It was quite bright, but started to tint shift after turning it on. The only causes that I can think of are my poor soldering, the heatsink just wasn't enough or it just couldn't stand the current it was getting. That makes me wonder though, because I ran a P7 on the same heatsink and had not a single problem when driven by a hipCC and 5AA eneloops. Oh well, here are a few pictures of the unit I built. The driver's gonna be cut off the heatsink and a 500mA buck puck be put in it's place. It should be a nice general purpose light in a 2D maglite.