L1 circuit coffin removal

[tylerdurden]

I got the circuit out of the L1 without destroying it. It now freely slides in and out, but works fine.

The circuit resides in a "coffin" (as Don calls it) in the top of the battery tube. It's a little bit shorter than a 123 cell.

There are 8 barbs on the plastic cap at the top of the L1 battery tube. The four larger barbs can be gently pried inward with a fine-bladed precision screwdriver. The other four are pretty rigid, so I just cut them off with an exacto knife. /ubbthreads/images/graemlins/smile.gif By leaving the four larger barbs attached, I've left open the possibility of re-securing the coffin. You can just leave them pried in, though, but the coffin will slide in and out of the tube freely. This isn't really that big of a problem since the head generally stays screwed on.


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Upon extracting the coffin, the first thing I thought was "that's it?"


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Now if we could just figure out how to boost the output of this circuit. The 1.5 ohm (I think) resistor (marked 1R5) looks similar to the 1.0 and 0.1 ohm resistors that control the output of the KL1 circuit, but I have no clue if the function in this circuit is similar. Since this is the only L1 I have right now, I don't intend on experimenting.

 

[tylerdurden]

BTW, it seems to me it would have been much easier to build a two-stage tailcap that would have fit the E-series battery tubes and just package that tailcap with a KL1 and either E1e or E2e battery tube.

Of course, the L1 that we have now does give us the ability to build cheaper dumb heads, but SF never capitalized on this capability themselves by selling the different colored heads seperately.

 

[McGizmo]

Tyler,
I picked up the term coffin from PK, he gets the credit. I would also guess that the Lumimax series is still in its infancy and some of these components and design considerations might evolve in manners which will make more sense as time goes on.

 

[tylerdurden]

Something tells me that the engineering department had one thing in mind (i.e. availability of cheap dumb heads) and the marketing department squashed that before it got to market. At least, that's the way it works at most of the places I've worked.

 

[Xrunner]

Tyler, any chance of a picture comparing the coffin with a 123 cell? Thanks

-Mike

 

[BC0311]

/ubbthreads/images/graemlins/popcorn.gif

Thanks for doing this, TD. Very interesting! /ubbthreads/images/graemlins/thumbsup.gif

Britt

 

[php_44]

The circuit is not what I expected. It looks like a generic 'HC14 which is a logic gate chip containing 6 inverting buffers with schmidt trigger inputs. There appears to be an assortment of small FETs or transistors and a large FET with inductor on the back side, along with a sprinkling of resistors and caps.

All this fancy speak to say it looks like a clever analog designer wanted to roll his or her own switch mode regulator "from scratch". Does this light act regulated or semi regulated in use? I would guess semi-regulated (Slightly declining brightness till the battery is nearly empty then a fairly rapid decline for the remaining battery capacity).

Thanks for posting the pictures!

A good sleuth might be able to determine the FETs/transistors and diodes used by the SMT markings, then deduce the circuit. Though I honestly don't have the time right now - I'm very interested to see the circuit if someone else has the time!

 

[tylerdurden]

[ QUOTE ]
Xrunner said:
Tyler, any chance of a picture comparing the coffin with a 123 cell?

[/ QUOTE ]

 

[Ralf]

Re: L1 circuit compared with KL1

I think its cheaper than the KL1 circuit, if you
buy if this is really an ordinary MOS logic HC14 ...
But they had to develop both the KL1 and the L1 ciruit,
therefore the question is really why SF does this much of
circuits. But I heard rumors that at least the KL1 and the KL4
ciruits are basically the same.

How does the L1 ciruit compare to the KL1 circuit in
efficiency?

Cheers
Ralf

 

[StoneDog]

Re: L1 circuit compared with KL1

Any chance the board could be replaced with a BadBoy or MadMax? How wide is the "coffin" and is L1 body tube the same bore throughout?

Jon

 

[tylerdurden]

Re: L1 circuit compared with KL1

The tube is mostly the same bore, but there is a bulkhead in the middle that seperates the coffin half from the battery half.

It should be possible to mount a BB or MM in the coffin, but I haven't actually tried it, and I don't have an L1 anymore. /ubbthreads/images/graemlins/frown.gif

 

[funder]

Re: L1 circuit compared with KL1

I just done the same job /ubbthreads/images/graemlins/smile.gif /ubbthreads/images/graemlins/smile.gif, but after that, I remove all barbs for the convinience of circuit test.

Any one knows how to get out the tail switch board and nut? I get out the boot cap and rubber boot but found it is no help. /ubbthreads/images/graemlins/frown.gif /ubbthreads/images/graemlins/frown.gif

 

[McGizmo]

Re: L1 circuit compared with KL1

Funder,
The button has a male plug that is glued/ pressed into the top half of the switch module and keeps the module captive in the shell. You need to pull the button straight out of the module. If you have a fork, place it under the button and pry it straight up. If you pry at too much of an angle, you can break the plug or stem off in the top half of the module. Been there, broke it. /ubbthreads/images/graemlins/icon15.gif

 

[akula88]

Re: L1 circuit compared with KL1

Funder,

How did you remove the boot cap? Just by plain twisting? or you heated it up?

Thanks.

 

[funder]

Re: L1 circuit compared with KL1

Have done it an hour before, pull the board and switch out by a plier. Now the plastic stand is shortened and the spring is adjusted to fit the length of 2 123A or 1 168S(maybe 168A after some further work)

akula88: As McGizmo says,heating is most efficient way to break the glue, I used the boiled water and keep the tail switch in the water about 10 mins(if doesn't work, try to keep it for a longer time) and after that, it can twisted out by a plier.

 

[StoneDog]

Re: L1 circuit compared with KL1

funder: Do I understand you correctly, you were able to get 2x123 into an L1? I know that McGizmo has done this but he used a PR-T head and a shorter e-can. Were you able to use the existing L1 head?

I wonder if maybe the coffin could be shortened (and the circuit replaced) and then use a Pila 150S or possibly 2xCR2...

Jon

 

[funder]

Re: L1 circuit compared with KL1

Yes,I intended to do so, The head I used is Aleph1.The can of the LE should also be shortened, and an ring was used to add the height of the edge to make sure the body can contact the can(ground). The spring of the tail switch need to be shortened and adjusted(or replaced) the the plastic nut was shortened, too.

 

[McGizmo]

Re: L1 circuit compared with KL1

funder,

If you measure across the flats of the battery tube and then consider the bore diameter you will need for 168A, I believe you will find the tube will be paper thin at the flats. Now if the new L1's have the radiused engraved panels, there may be enough wall thickness. /ubbthreads/images/graemlins/icon3.gif

 

[akula88]

Re: L1 circuit compared with KL1

Jon/StoneDog> I used any E-series head with my bored-down L1. What's interesting (challenging) is the length of the tube. The L1 circuit + a CR123 is 63mm. A Pila150s is 53mm; while Pila168s/2xCR123 is 68mm.

Funder> I'm waiting for another tailcap in the mail. It's more difficult to look for a BK tailcap than an HA. I'm also currently using an Aleph3 with Pila150s, but the tube is up to other purposes.

I really like the form of the L1 body. Its perfectly 'curved'; middle thinned downed, while the tail goes up a little in diameter.

Here's another one.
L1 tube with an L4

 

[funder]

Re: L1 circuit compared with KL1

McGizmo, you are right, the diameter of the L1 tube is smaller than other SF's, I have to file it a bit to fit the 168S now. It can hold a 168A after further filing but at the risk to make the tube flimsiness. It seems that I have to resist the temptation for higher battery capacity( now 18650 Li-on have 2500 mah and 17670 have 1700 mah)

akula88, I agree with you, the L1 is one of the most beatiful bodies of all SFs. to make it fit a 17670(168S) or 2 123A, we have to fight for every mm, and the consequence is we can have the most compact 2-123A SF.