KX2 on R123 - how is it?

Hey folks,

I've spotted my dream light. A Surefire HABK E1e, and a HABK KX2 LED conversion. Since the KX2 is no longer a buck/boost module, I'm going to have to run this on R123's. Has anybody run theirs on R123 yet, and what is your opinion? Even better if you could do runtime plots.

I am extrapolating from another CPF'ers work running the KX2 on a 17670 (1400mAH). Halving his runtime gives me a good guesstimate of what I can expect from a 700mAH battery, but really, it's still a guesstimate.

Let me know if you have used this configuration. Finally, my HABK E1e/KX2!!

IIRC, with a single R123, the KX2 is going to have very limited runtime - I'm guessing 2 hours or less. I'll try this combination tonight and post my results. I don't have the capability or know how to do a runtime plot though.

I have a similar build in the works, but with an E2D body so I can use a 17670. It'll be a Cree "E2L-BK".

Just found this thread regarding runtime with a single R123:
https://www.candlepowerforums.com/threads/182299

While they are half the size and rated at half the amp hours, the runtime on the RCR123A with the KX2 will be considerably less than half of the 17670's runtime.

Sounds interesting though! Keep us updated if you go with this setup.

Hi,
Here is a thread for E2L Cree with 14650 (about same capacity than RCR123), 140 mn full regulated :
https://www.candlepowerforums.com/posts/2084548&postcount=50

Another setup : E2L Cree with 17670 (great !)
https://www.candlepowerforums.com/posts/2128901&postcount=1

Regards,

Very nice, thanks!!

My existing setup is an E1e+KL1. Old 3rd-gen KL1 with fins, NX05 optic and Luxeon 1. I like it just fine. 90 minutes in regulation before it starts to fade. 90 min has always been enough for me, I've never actually run out of juice on this light, so I'm thinking 2 hours is very good. Plus KX2 is brighter than this old 25 lumen light.

If I needed extreme runtime I'd pack my U2.. now that is RUNTIME

I'll think about whether I want to pony up the cash. I have a Fenix LOD CE in red, the Christmas special edition, on the way. I might play with that first.

I forgot all about doing the test until late last night. I put an AW RCR123 into an E1L body and screwed on a KX2 head. Initial output does not seem to be as bright as when using two primaries. I stood the light on its Nekomane tailguard and walked away to take care of some things. I checked on it every 15 minutes or so and noticed no flickering. After one hour, brightness seemed to be same. By two hours I was ready for bed and couldn't continue the test. Output seemed to have diminished slightly by this time, but the KX2 was still putting out plenty of light with no signs of flickering.

I was fully expecting the KX2 to drop out of regulation by 1:30 or 1:45 (hours into the test). Either that didn't happen, or if it did, I didn't recognize it.

Sweet! That makes it a viable option for my purposes, thanks a lot for the update!

That really is good runtime with 14670 and 17670's. The big help here is the low current to the led, under 200mA's, and the resultant very low vf, allowing the LiIon's to run the KX2's buck circuit in regulation for quite awhile. A lot of lights would not be doing so well, using a buck circuit and a starting voltage of 4+ volts. My modded KL6 with a P4 Cree, running at 1 amp to the led might stay in regulation for about 3 minutes using an 18650. Of course the culprit here is the very high current to the led putting an extreme demand on the single 18650.

Bill