L1 with PR-T head

Hi guys,

I finally took a break from builds and did something fun.



MORE INFO; Click here

Making a "dumb" head of the PR-T was pretty easy and quick with access to a lathe for some simple parts. Since so many of you now have lathes, I figured I'd post about this mod. The PR-T provides for a pretty useful beam pattern in both low and high modes and this was my first chance to see what a reflector with two radically different levels of output would be about. I like it so far and will play with it, I mean test it, some more. /ubbthreads/images/graemlins/tongue.gif

So since I also anticipated the knee jerk request for a beam shot, I went to the trouble of comparing this to a (from L to R) stock L1, L1 with HD and Fraen LP and then the PR-T.



And the relative Lux measurements from approx 1 meter; 190, 480 and 1320

Ergonomically, the L1 with PR-T is very nice and comfortable.

I am not certain at all of the viability but I am wondering if the L1 can be gutted and host a PR-T-917 head and 2xCR2 cells. Further, I am wondering if the two stage switch can be used to drop the DB917 out of regulation??!?! It all sounds good but only one way to find out! /ubbthreads/images/graemlins/tongue.gif /ubbthreads/images/graemlins/grin.gif If any of you electronics guys care to throw up a red flag prior to me turning a perfectly good light into a pile of poop, please speak up! I tried a 22 ohm resistor in the tail of a 917 on 2x123 and saw a 2.5 volt drop with 100 mA going through the resistor. Sounds like a 1/4 watt requirement to me? Anyone know the capacity and value of the stock resistor in the L1? Dang, Off topic here in the first post! /ubbthreads/images/graemlins/tongue.gif /ubbthreads/images/graemlins/grin.gif

Great ideas, Don! /ubbthreads/images/graemlins/thumbsup.gif

/ubbthreads/images/graemlins/popcorn.gif

This is very interesting and exciting. I'll want one of these, so I'm placing dibs.

Britt

Don,

I'm looking for a McLux PR-T bare aluminum. The Shoppe isn't offering these beauties but maybe you still have some?
I need only one, so if available please PM or email me.

That's a real beauty! Plus you get dual switch. Very nice indeed!!! /ubbthreads/images/graemlins/cool.gif

Hi Guys,

I gutted a L1 and bored out the partitioning bulkhead within. I added a 1/4" long battery extender in line with two CR2 cells. I put a PR-T-917 head on the front end and swapped out the 10 ohm resistor in the tail switch with a 33 ohm 1/4 watt resistor. In low beam, the circuit draws 79 mA which I believe is for the most part passed through to the LED. In high mode, the LED gets the 917 mA. From roughly a meter, the relative lux readings were 350 and 2600. I'm going to add a tab to this for swivel belt carry and I think I have a new EDC for a while anyway! /ubbthreads/images/graemlins/grin.gif

Congratulations, Don!

This is what I've been waiting for. All the good attributes of the SF L1 radically improved with the kiester-kickin' high performance of you PR-T 917ma Lux III head.

Britt

Very nice Don. I'm kinda sorry I bought a black Original PR head last week - I think I like these PR-T's a lot better!

Jon

yah !!! DON did it again !!
/ubbthreads/images/graemlins/thumbsup.gif
bernhard

OK! Finally found this! Man, it's hard to find posts on cpf these days....

I'm coming over right now to take a look (and steal it)!!!
/ubbthreads/images/graemlins/grin.gif

What would be the benefit of converting it to run on two CR-2 Lithium cells rather than the one CR123A Lithium cell?
/ubbthreads/images/graemlins/thinking.gif
Currently, I don't have a light that uses the CR2. But with them about the same price as the CR123A from The Battery Station, if the benefit is significant, I could easily feed it.

Britt

[ QUOTE ]
BC0311 said:
What would be the benefit of converting it to run on two CR-2 Lithium cells rather than the one CR123A Lithium cell?

[/ QUOTE ]

To build a variable-output 5w light?

what do I win? /ubbthreads/images/graemlins/smile.gif

Heh heh /ubbthreads/images/graemlins/grin.gif.

TylerD, you know, I hadn't even considered a 5 watter. That's an idea, though.

It's just that I find the PR 917 Luxeon IIIs are such a good combination for my uses.

Although, having the stock head modified to emphasize flood rather than throw would be a very practical capability for me. I just wonder if a 5 watt Luxeon would be more heat than the increased output would be of practical use to me.

I am ignorant concerning the arcane knowledge of thermal issues, but the two McLux PR-917 Lux IIIs I have handle heat superbly and don't get very hot.

The SF L4 I had for a time got pretty durned hot. /ubbthreads/images/graemlins/crazy.gif

If I were to have a 5 watt in a Surefire, I'd probably look into having one put in the KL-3. But, I better shut up cuz the L4 was voted like the mostest favorite light on CPF for 2003. I'm learning not to knock the other guy's favorite. /ubbthreads/images/graemlins/grin.gif

Britt
Edit PS: I just got an email and found out I have been confusing two different SF L1 modding approaches.

I just bought an L1 and I'll want to stick with the L1's basic setup and purchase a "dumb" head for it.

So, I won't be going for the "gutting" and conversion to two CR2 cells.

When you're done having fun and start building again, let me know if you have an old L1 917 Lux III on 2 CR2s that was your EDC for a while and could be mine, since you came up with something even more amazing.

Britt,

The advantage, as I see it, is more battery capacity and the ability to have the high beam at 917 mA as opposed to stock which is somewhere around 400mA?? The stock configuration is very useful to be sure!

Of course the L1 with 2xCR2 can also host the KL1,KL4, KL3 & KL5 via E2C and any 6 volt PR heads. Like the combo shown below:

Thanks, Don. Man, that's a beauty, great photo of it, too.

Britt

Thanks Britt. I forgot to mention that the two stage switch works for all of those heads as well. The resistor seems to dictate the current at about the same level, regardless of what's up front. I suspect the electronics guys could explain this.

Has anyone managed to boost the output of the stock L1 circuit? I like the idea of having the brain in the body so I can have a variety of cheaper dumb heads. I suppose a small extension might be needed to run 2xCR2 if the innards aren't gutted.

Tyler,

I think CM has a handle on the circuit. An extension for 2xCR2 certainly would be required.