Surefire L4

Just received my new L4, wonderful light for my purpose. I bought this light on an impulse after a demo at the local Cabela's. Before doing any real homework I also purchased a rechargeable battery kit. The batteries in the kit are labeled TR16340 1000mAh. After reading here I have a good idea what this battery is and what it's capabilities are.

After reading in this forum for the last three days I have found a massive amount of great information. From what I see it looks like I am rolling the dice using 2 of the 16340's. There are a few stories of success but I have yet to read that anybody damaged their flashlight using the 16340's. I am willing to try because the reward in the long run is worth the risk.

I do have a few questions that I have not seen answered:

The S/N on the the KL4 head starts with C. I have not seen this referenced anywhere on this site. Does anyone know what this means? The LED looks identical to the pictures I have seen posted here of the "B"

I have read "beware the wrath of Surefire" in reference to using rechargeable batteries. What is the wrath and how would they know I have used rechargeable batteries?

Lastly, I would like to thank everybody here for a wealth of great information, if I would have come here first...

I would imagine the "wrath" in question is them not replacing your light/head if you burn out the LED by putting too much voltage through it using Li-ions rather than SF123 (Surefire CR123s) batteries.

I believe they can be reasonably sure if you used rechargeables by the nature of the failure. If you can find a KX2 head (Have not been on the SureFire site for a while so do not know if they are still available) you may be able to turn that into a E2L as well. I did that and by doing so I keep the KX2 head on for about 80 lumens for 7 hours or 3 lumens for about 70 hours. With the TIR optics it is a surprisingly useful 3 lumens. Makes for a great little survival light and I LOVE the beam profile of the KX2 head. Plus if I need flood I can just switch back to the KL4. My L4 was an older version and my KX2 head was also unique in that it had a lightly frosted lens and I am not sure if they still use that or are clear lenses.

Hi everybody,
I've been running an older 100 lumens L4 with a 17670 battery for a while . Thanks to the "Legoable" Surefire versatility I put the KL4 head on an (older) E2l tube that was wide enough for the 17670 (just had to scrap the plastic label). The result: an awesome and guiltfree use torch.

Anybody have any information on the KL4 with a "C" as the first letter of the serial number?

Marka683 said:

Anybody have any information on the KL4 with a "C" as the first letter of the serial number?

Click to expand...

Maybe they've upgraded the KL4 to a different type of LED again and wanted to further differentiate between the models (I know you said your emitter looked like the "B" photos, but maybe it's a little different". Specs haven't changed on the Surefire website though. This question would probably be best answered by forum member Size15's.

Two things come to mind (although it is 2am)

Either SureFire made so many KL4 bezels that they exhausted the "A" and "B" serials,
or
The C indicates it's a newer KL4(A) version. I don't recall right now whether they actually labelled the KL4A with an A...
A photo of the LED would help, as would a photo of the bezel showing the serial number.

I believe all the "A" models were indeed labeled as "A"; both of mine were.

Howecollc,
Thanks for the photo - it shows "KL4" rather than "KL4A" so if it's a newer so-called "A" version.

From what I can tell, when SureFire switched from the Lux V LED (rated at 100 lumens) to the SSC P4 LED (rated at 120 lumens), they didn't change the bezel's model number (KL4 didn't become KL4A) like they did with the KL5.
Instead, they started the serial number with Bxxxxx (instead of Axxxxx).

It is therefore more likely that KL4 bezels with Cxxxxx serial numbers are continuations of the 120 lumen version. Either because they ran out of Bxxxxx numbers, or because they've made another change. I think the former is more likely.