Cree XP-G R5 320-Lumen White Light LED Drop-in Module 18V Max in Surefire G2

I know I'm a behind, and this will be remedial, but maybe someone will gain something from this. Given the 18V max I thought that maybe I could push it with various battery configs to get it to put out close to the 320 lumens. I mean it is way brighter than the P3 that I had, but it didn't matter the config. 2X AW 18560 3100maF; 1X AW 18650 3100maF, 4 RCR, 2RCR, the output was the same. So I just decided to use these to replace the G2 drop ins and run them on 2 RCR. I'd heard heat was an issue, but that seemed doubtful to me as the output isn't that robust, but I ran it continously for 20 minutes and the head got only slightly warm as was the case with the batteries. Certainly a huge improvement for the G2 and the heat doesn't seem to be a problem, so it seems appropriate for the G2. The drop in fits nicely without the spring and it's beam is nice as it's a good bit more floody. But by contrast to the XML U2 it's comparitavely anemic.

For what it's worth.

Buckfever said:

I'd heard heat was an issue, but that seemed doubtful to me as the output isn't that robust, but I ran it continously for 20 minutes and the head got only slightly warm as was the case with the batteries.

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Max current for a G2 is about 500ma (half an amp). You're not going to get more than 200L at that level. More than that, the heat will build up inside the light and slowly cook the LED, etc. If after 20 minutes, you are removing the bezel and the drop in itself feels slightly warm, you're not getting 300L and it will be fine.

ElectronGuru said:

Max current for a G2 is about 500ma (half an amp). You're not going to get more than 200L at that level. More than that, the heat will build up inside the light and slowly cook the LED, etc. If after 20 minutes, you are removing the bezel and the drop in itself feels slightly warm, you're not getting 300L and it will be fine.

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Thanks. I really wish I could learn to understand how many amps are going to be pushed by a particular lamp/battery combo. Is that entirely a function of the driver?

In theory, its a function of the LED, driver, and battery (voltage). In practice, it usually comes down to the goals of the person/people putting it together. For example, most modules are going to sell you on their output. Since more power equals more output, most modules are going to made as powerful as possible.

But its up to you as a buyer to decide if the power level is to much for your setup. Most modules are 'expecting' a metal socket, so will be to much power (heat) for reliable operation in a G2.

One good way to obtain just a little 'safety margin' for the LED modules in the nitrolon G2's is to use a single 17670 cell rather than two LiIons or 2xCR123's. The driver will often deliver close to the rated current for the LED, but it will not be driven at maximum; heat generation will be somewhat less and might make the difference between an overheated module and one that will work over the long term.

Buckfever said:

[...] I ran it continously for 20 minutes and the head got only slightly warm [...]

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Please be aware that a relatively cool head/bezel assembly may mean that insufficient heat is being conducted to the outside surface. If you really want maximum outputs I would highly recommend an all-aluminum light.

Hope this helps,

Kestrel said:

One good way to obtain just a little 'safety margin' for the LED modules in the nitrolon G2's is to use a single 17670 cell rather than two LiIons or 2xCR123's. The driver will often deliver close to the rated current for the LED, but it will not be driven at maximum; heat generation will be somewhat less and might make the difference between an overheated module and one that will work over the long term.



Please be aware that a relatively cool head/bezel assembly may mean that insufficient heat is being conducted to the outside surface. If you really want maximum outputs I would highly recommend an all-aluminum light.

Hope this helps,

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I should of been more clear. I have all kinds of confiigurations that I can build with. In this particular case after trying all iterations and seeing as apparently the driver would not let me increase the output I settled on just throwing it in the Nitrolon. I was hoping to push this lamp with 2X18650 but also be able to go with 4 cr 123a primaries in a pinch, but the output was so weak that throwing them in the Nitrolon was really the only use I could come up with for them.

It's interesting to me that just because the emitter might have a particular potential, if you don't know how the driver is going to regulate it, it's pointless to talk about the Output. I wonder if the vendors even know what the drivers will allow on the build they're selling.

Buckfever said:

just because the emitter might have a particular potential, if you don't know how the driver is going to regulate it, it's pointless to talk about the Output.

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Adding to the confusion, economy modules are listed according to potential/theoretical output of the LED. Then its combined with whatever driver is handy. As a general rule, for example, huge voltage range (2-18) on the same device is a bad sign. Another is when the LED itself is the primary name:

CREE 300 Lumen Drop in

When the most valuable 'feature' is a $3 part (the LED), you have to wonder what the rest is made of.