gadget_lover's L4 dimmable mod review

[Frangible]

gadget_lover\'s L4 dimmable mod review

gadget_lover modified my L4's Z57 clicky tailcap to be dimmable by means of a resistor reducing the power drain to 60 ma... which is about 1/4 of a watt. This seems to be about twice as bright as an Arc AAA, or about 6 lumens. Obviously, depending on resistor, it can be pretty much any brightness level.

Adjusting the brightness is dependant on how far the cap is screwed in. Tight = bright, slightly loose = dim, very loose = lockout.

I couldn't get a very good picture of it, and it's not immediately obvious looking at it anyway... but you can see a resistor leading peeking out. I tested it for durability and it held up well.

Battery life was quite good, but I lack the equipment to time it. Suffice to say it's far in excess of the original.

I took the light on a night walk and the lower power setting was great. The default was a bit too bright, and the lower power setting let me see where I was going without killing my night vision or flashing people in their houses.

This mod adds a ton of versatility to the L4. As great of a light as the L4 is, sometimes the runtime is too short, and sometimes it's just too bright.

I certainly don't want to go back to only having one brightness level. It's pretty much like two flashlights in one, now.

Unfortunately though, there is one drawback worth mentioning: you have to unscrew the tailcap a lot more before the light will lock out. However, this is a minor inconvience for the added versatility.

This is definately a great mod, and makes one of the best flashlights on the market even better.

 

[jtice]

Re: gadget_lover\'s L4 dimmable mod review

That sounds great ! /ubbthreads/images/graemlins/smile.gif
I am looking forward to this, I have one of gadgets dimmers for my Arc LS, and its fantastic.

The L4 would be great dimmed like this.

Thanks for the review.

-John

 

[DBrier]

Re: gadget_lover\'s L4 dimmable mod review

Try unscrewing the head for a lockout instead of the tail.

 

[Frangible]

Re: gadget_lover\'s L4 dimmable mod review

Yup, if you barely unscrew the head it works as a lockout. Good call.

 

[LEDagent]

Re: gadget_lover\'s L4 dimmable mod review

Is the constant on (clicky) feature still retained?

 

[Frangible]

Re: gadget_lover\'s L4 dimmable mod review

Yes, constant on, and momentary on both still work as normal, with either bright or dim modes.

 

[PaulW]

Re: gadget_lover\'s L4 dimmable mod review

[ QUOTE ]
Frangible said:
gadget_lover modified my L4's Z57 clicky tailcap to be dimmable by means of a resistor reducing the power drain to 60 ma... which is about 1/4 of a watt. This seems to be about twice as bright as an Arc AAA, or about 6 lumens. Obviously, depending on resistor, it can be pretty much any brightness level. . . .


[/ QUOTE ]

Do you know what the value of the resistor is? My rough calculations indicate that to get 60 ma would require about 50 ohms when the supply is 6 volts (a 3 volt drop across the resistor. But if the supply is a Pila 168s (resulting in approximately 0.7 volts across the resistor), 50 ohms would give only about 14 ma.

I would think that Pila users would want a smaller resistor. I ran a little test on my L4 using both 56 and 33 ohm resistors and almost fresh batteries and found that I prefer 33 ohms. The downsides of using smaller resistors, of course, is decreased run time and increased power heating the resistor.

My data for measured current and calculated power are:

. . . . . . . . . . . . . . . . . . . . Power
Res . . . Bat . Current . Res . . . Light
Ohms_Type___ma____mW____mW
56 . . . Pila . . . 30 . . . . 50 . . . . 60
56 . . 2x123 . . 63 . . . .220 . . . 160
33 . . . Pila . . . 50 . . . . 82 . .. . 100
33 . . 2x123 . .104 . . . 360 . . . 270

Paul

 

[gadget_lover]

Re: gadget_lover\'s L4 dimmable mod review

The resistor is 1/8 watt, 68 ohms. The measured voltage drop and current gave right at 1/8 watt dissipated by the resistor. A lower resistance would require a higher wattage resistor.

As Paul indicated, a different power source would call for a different resistance.

I generally calculate the values, then test to ensure everything is within spec. There are enough variations betweeb different lights that one value will not work for everyone.

EDIT: I should have said one value will not PLEASE everyone. Some expect brighter, some expect dimmer.

 

[PaulW]

Re: gadget_lover\'s L4 dimmable mod review

Daniel,

Thanks for the clarification. I, for one, would prefer about twice the light that a 68 ohm resistor gives. But I think I understand from what you say that we are limited by how much heat the resistor can dissipate. Does the geometry of the setup require nothing larger than a 1/8 watt resistor?

I ask because it would be nice to have a lower resistance for use with Pilas (perhaps 33 or 39 ohms). Yet, I would also want to be able to use 2x123 when necessary without having to be concerned with the resistor burning out. I think that would require 1/4 watt.

However, assuming that the beta tests end well, and it looks like they're going to, I will want to have the mod regardless of the limitation. And if 68 ohms is the smallest you recommend using, I'll gladly take it.

Paul

 

[gadget_lover]

Re: gadget_lover\'s L4 dimmable mod review

Paul,

The space limitations are pretty tight, but a larger resistor is possible if I
1) use two 1/8 watt side by side or
2) embed the larger resistor in the plastic of the tailcap.

I prefer not to cut up plastic whenever I can avoid it due to the possibility that it might weaken the part.

Daniel

 

[PaulW]

Re: gadget_lover\'s L4 dimmable mod review

Thanks. That makes sense.

 

[Reno]

Re: gadget_lover\'s L4 dimmable mod review

Will this mod work on the old-style non-clickie E2e tailcap? Just got a KL4 on an old body /ubbthreads/images/graemlins/frown.gif

 

[gadget_lover]

Re: gadget_lover\'s L4 dimmable mod review

Reno; No, this particular mod does not work with the old style, though I think that I could probably come up with something eventually. Mc Gizmo's already working on those.

Paulr; I just sent a 33 ohm 1/4 watt to my second beta tester. We'll hear about that in a week or two.

Daniel

 

[PaulW]

Re: gadget_lover\'s L4 dimmable mod review

[ QUOTE ]
gadget_lover said:
. . . I just sent a 33 ohm 1/4 watt to my second beta tester. We'll hear about that in a week or two.

Daniel

[/ QUOTE ]

Thanks. That's good news for us Pila enthusiasts.

Paul

 

[Phaserburn]

Re: gadget_lover\'s L4 dimmable mod review

GL, how goes the L4 mod? I'm curious for news (re: I want one).

 

[gadget_lover]

Re: gadget_lover\'s L4 dimmable mod review

It sounds like the mod is a solid one. I've not heard back from my second tester, but he's is Europe so he may not have gotten his back yet.

See the other thread for discussion about the mod.