KL1 vs. KL4

pjandyho

Flashlight Enthusiast
Joined
Oct 29, 2003
Messages
5,500
Location
Singapore
I had a high dome KL1 which I have been EDCing on my E2e for a month or so. Today I bought an E1e from a fellow CPFer so that I could use up all the used batteries from my M3. I was happy with it but I wanted to see how the KL4 would perform on an E1e body. Then came my friend.

My friend had a KL4 which he EDC everyday on a Vitalgear body, similar to the TW4 package. We compared the 2 lights. Both seem to output the same amount of light but my KL1 throws just a little further because of the optic. The KL4 has better flood. Now remember this, we are both using a near depleted battery with mine being slightly weaker. We swop batteries. It turns out my KL1 is still running strong and bright on his battery but my friend's KL4 is a whole lot dimmer on my battery. After that swop back our batteries again and my KL1 still output the same amount of light like as if it is using a new battery.

Why is this so? Does this mean that on a single cell light the KL1 has better efficiency than the KL4? I am confused since there are so much hype about the KL4's efficiency improvement using an E1e or Vitalgear body and no one is talking about the KL1's efficiency.
 

luxlover

Banned
Joined
Feb 17, 2004
Messages
3,223
Location
Brooklyn, New York
Andy,

I also have a KL4 bezel with an E1e light. I am with you in that I would like some well informed CPF member to answer this question. The KL4/E1e combo sure puts out a nice, balanced beam of light. There are great differences between the KL1 and the KL4 which I am not aware of, beside the number of batteries needed. I hope that you will get some good contributions.
 

Chop

Flashlight Enthusiast
Joined
Jul 22, 2003
Messages
3,635
Location
Louisiana
First of all, comparing the KL1 to a KL4 is like comparing apples and oranges.

The KL1 has a 1W luxeon running at about 350mA with an NX05 optic. The KL1 is also designed to run on anything from 1 to 3 123 cells, so it has a buck/boost circuit in it. Buck/boost circuits are inefficient, but flexible.

The KL4 has a 5W luxeon in it that runs at around 660mA when run on two cells. The KL4 employs a straight boost circuit and it is more efficient than the KL1 circuit. Since 5W luxeons have such a high Vf and are power hungry, you really can't drive a KL4 at 660mA with just one cell, so you get reduced output from a KL4 running it on a single cell body. I've found that the KL4 circuit runs at about half of its bias when run on a single 123.

The only way to do any kind of comparison would be to start off with a fresh battery in each light. Both the KL1 and KL4 are nice for what they are. The KL1 will put out less light than that the KL4 running on one or two cells, but the KL1 may give the impression of being just as bright because of its throw, but the 5W will put out more overall light in a flood pattern, characteristic of 5W luxeons with small reflectors. You also have to note that the KL4's performance will on one cell will be largely dependant upon the Vf of the luxeon.

If you really want to compare the KL1 to the KL4, put them on 2 cell bodies. You'll really be able to see the difference when you do a ceiling bounce test. The KL4 does put out more light.

If you are looking for a pocket light, you have to decide what you want. Flood or throw.

As for the KL1, I'd invest $5 in an IMS reflector for it. You'll never go back to the optic.

You have to keep in mind that the KL1 was designed as an LED conversion with runtime and dependability in mind, not performance. The KL4 is actually the head of the L4 light that is advertised as a performance light.

Like I said, you're comparing apples and oranges. First, you should retry your comparison with fresh batts. Both lights have their pluses.

I do have to say that I still find the KL1's to be real gems. Their buck/boost converters make them really flexible and if you overdrive the circuit to about 700mA and add the reflector, the KL4 won't be able to touch it in terms of throw.
 

pjandyho

Flashlight Enthusiast
Joined
Oct 29, 2003
Messages
5,500
Location
Singapore
Thanks chop, I love your detailed answer of which some I already know. I had gotten a KL1 over the KL4 because of the longer run-time on a 2 cell light, 4 hours vs 1 hour on the KL4. I know the KL4 is a lot brighter than the KL1 when 2 cells are used but we are all talking about EDC using an E1e body and that leads me to test which functions better. Logically the KL4 can never output the same amount of light on single cell as compared to the 2 cells it was originally designed for which is why I did this test to see which works better on a single cell body.

You told me to get an IMS reflector for the KL1 but does it throw better than the NX05 optic? What I like about the optic is that it gives a decent throw and has a very nice side spill. How and who do I get the reflector from? How to I mod it?

Thank you so much.
 
Top