Will KL4 Head Work on a 1 Cell 123 Body?

Will my E1L or FB1 body power my KL4? Is it even safe? If so, what output and runtime can I expect?

Thanks,
Jeff.

That configuration was dubbed the TW4,

We have found that some KL4s work on a single cell, and some dont.
Bare in mind, even the ones that do, are a good bit dimmer than on 2 cells.
But its still a decent amount of light for the size.

~John

Thanks. Any concerns about affecting longevity of the head with this setup? Any measurements on light or runtime? This accountant doesn't know electronics at all, so any help is truly appreciated.

Thanks,
Jeff.

Sorry, dont have any runtimes or output ratings for this setup.
Its under half the brightness though.

No harm will come to the KL4 head running it off one cell.

~John

PseudoFed,

No. Since you are subjecting the head to a "lower" voltage than it was designed for, rather than "higher", the longevity will be better, not worse. I have heard (but I'm am not the one to speak knowledgeably about it), that you can solve the problem of the "TW4" setup being dimmer by using a 3.7v rechargable in this setup, and that now you would have both small size and far brighter illumination. I have heard that runtimes are fairly short (15minutes?) with this setup because of the single battery, but the light now seems to perform as desired. There are several "TW4" ("TW-4"?) threads on the forum from a while back but I don't know how to access them. I went another way and had Milkyspit build a couple of 60-lumen "old" L1 heads to screw on the front of my E1e/Z57s. Beats the hell out of a TW4, but costs $165 each.

Hope this helps,
Flashdark sends.

Yes the KL4+E1e aka TW4 works fantastic with one R123 (3.7 volt) rechargeable Li-Ion cell. It runs in full regulation for 20-25 minutes on a 750 mAh cell. No risk of destroying the LED, but the light does get quite hot after 10 min or so, depending on whether you hold it in the hand, walking with it or leave it turned on on the desk.

A cheap setup is a Nano charger with one or two protected R123 cells bought from either AW or Lighthound. Unprotected *can* be used, but you'll have to switch off the light as soon as you see it dimming down. Otherwise you'll ruin the cell.

Jan

Pretty much the same as everyone already said. Run a 3.7v RCR123 rechargeable in it and it'll be plenty bright. Mine lasts over 30 minutes at full brightness.

TW4 with R123 and two stage switch makes one of the best pocket rocket around!

for max lumen output this is one of the smallest LED lights available. it's not unusual for find KL4's with 100+ lumen output. two stage switch is required as TW4 is too bright for most closeup work. extends runtime too.

best to use Don's two stage mod, but you can mod clicky by adding a simple resister too.

(I did a separate thread asking about the two stage switch, but) How does one acquire a two stage switch?

Thanks,
Jeff.

Yes, what of the we, the unenlighted many, who are much too timid to do our own modding to create a 2 stage switch? I've looked at some of the threads on setting up a 2 stage switch for the L4 and am concerned that my sausage fingers and caveman approach to delicate things will only cause the demise of my clickie. Is there a "2 Stage Switch for Idiots" guide?

PseudoFed said:

Thanks. Any concerns about affecting longevity of the head with this setup? Any measurements on light or runtime? This accountant doesn't know electronics at all, so any help is truly appreciated.

Thanks,
Jeff.

Click to expand...

Measurements of my homemade integrated sphere (shoebox*):

L4 with 2x CR123 (6.0V) 243 Lux*
KL4 on E1L-Body with 1x RCR123 3.7V (3.94V) 235 Lux*
KL4 on VG-FB1-Body with 1x RCR123 3.7V (3.94V) 238 Lux*

Just did a runtime plot on my E1L with K4 head and a Battery Station CR123. I like this setup - a useful/floody 25 lumens, with 140 lux or about 12 meters throw at beam center. Runs about 1.5 hours basically flat and 2 hours to 50%.

I did not do the runtime on a Duracell yet, but so far with limited use am getting readings almost 50% higher as compared ot the Battery Station (about 220 lux at beam center, providing about 40 lumens). Pretty impressive!

Thanks lightrod!
Now one with RCR123 3.7V... :naughty:

Xygen said:

Thanks lightrod!
Now one with RCR123 3.7V...

Click to expand...

here ya go...(call it 30 minutes to 50%)

:goodjob:
Thank you very much!
But shouldn't it say E1L/KL4?
I thought the KL4 would run regulated at 3.7V.

Xygen said:

:goodjob:
Thank you very much!
But shouldn't it say E1L/KL4?

Click to expand...

You're absolutely right - it should definitely say KL4 (says so right on the freakin' head! ). My bad....

lightrod said:

here ya go...(call it 30 minutes to 50%)

Click to expand...

lightrod,
That graph seems strange compared to my observations. Although I have never measured mine, I'm perfectly sure that the majority of the runtime is flat and in regulation using 1x R123. The output on mine seems pretty constant for 25 minutes, and it is real easy to detect when it falls out of regulation. YMMV I guess.

Jan

A common setup which a search of the forums would have yielded. This topic has been covered many many times even recently.


Above is a pair that I have set up. The parts for these are available at Lighthound.com
From a brightness to size ratio as well as from a lumen per dollar point of view these lights are a fine value. The KL4 head is one of my favorites and I almost always have one of these around as a backup EDC.
Surefire knows how to make a good LED head. The KL4 is certainly very robust mine do show signs of wear which adds character, but the quality of light is the same as the day I bought them.

Runtime? I don't know. I have never used one and completely run out of power in a single use. The 750mAh lithium rechargeables do a good job. I feel like it is about 30 to 40 minutes. Keep in mind the KL4 puts out a wall of light. It is no tight little beam. You may have to go through several KL4 heads to get one or 2 that you like the tint of. This may have changed with recent production. Generally the most recent KL4's that I have bought have been VERY bright and VERY bright.

Next time you have a question of this nature do yourself and the servers a favor. Search for the topic before posting a question. I say this because this topic has been covered many times with almost exactly the same answers to the same questions. As harsh as it may sound your question is not original. Sorry.
Enjoy your KL4.
Yaesumofo

PseudoFed said:

Will my E1L or FB1 body power my KL4? Is it even safe? If so, what output and runtime can I expect?

Thanks,
Jeff.

Click to expand...

Wow. I appreciate the feedback. Now, the following is with all due respect since I'm a relative newbie here. I did a search on "KL4" in the LED forum and reviewed posts back to May 2006. Only one thread asked my same question, and it was from mid-July or so. AND, it did not receive as complete an answer regarding output/runtimes as the nice folks above were kind enough to provide. Nor, did it ask whether it was "safe". Finally, a dozen or so flashaholics above were OK with seeing the question again.

I generally do searches in an effort to follow online etiquette. What I read about was "some" KL4s work with 1xCR123, and some do not.

In any case yaesumofo, I appreciate your response and your pics, which I also did not see in prior posts, unless I just did not review back far enough.

ETA: I guess in the future I need to state the obligatory "I did a search on ___, but it did not give me the answer I'm looking for".

Jeff.

Just remember this setup as TW4. Thanks to the new google-search, you can find such short words now.
I read that too, that some KL4's won't work on 3.0V primary CR123's. Mine does, but disappointing dim. I'd recommend rechargeable CR123's with 3.7V. As you see in my post above, the KL4 reaches the same brightness as with 2x CR123s.

Have fun!