Sr52 Teardown & Mod
My uncle approached me the other day and asked me for a light that could blind a bear. I decided to try and take him up on that one. He's thinking big but still comfortably holdable with one hand. I told him he doesn't need big to get bright but I think he wants something intimidating. I think he wants it big not to scare off the bears with the beam, but to make him feel macho. You know, then the bears won't eat you.
The most macho light I have is an sr52. Size wise that is. Output wise it's quite a wimp in my estimation. As I glance at this light from time to time it didn't sit right with me that I have a stubby cigar sized 18350 S41s making 3000 lumens and this 3x monster is barely barking over 1000. Anyone feel my pain? So I saw an opportunity.
Looking up modding options for this light didn't reveal any secrets. I only found reference to some vin modded lights and rmm mentioned something as well. Nothing documented though. So I had to use my own brain and laid out my options. I found it wasn't that easy to think up a good match for this light. I really wanted to put in an xhp50.2 emitter but the driver options were quite limited. Since it's a three cell light I would have to either convert it to a series configuration and use a buck driver or keep it parallel and use a boost driver. Both of these options make it difficult to provide the amps needed to overdrive this led. There's the mnt max buck driver and that's the only adequate driver they came to mind.
There's one more request of my uncle that limited my options to none. He's a techy gadget lover kind of guy. That means it's got to be programmable. I fell back on a TA driver running Narsil and going direct drive with an xpl2.2 emitter. This should give me over 2000 lumens if done correctly. I really wanted to make the light brighter with more flood but I couldn't think of a satisfactory way to make it happen. Maybe multiple emitters, but I wouldn't know how to find a good reflector that will still give some throw.
Opening Olights in the past has been a pain. I successfully opened a couple and ruined two s30s early on and have since given up. Until now. The solution for this light was to wrap it one time with packaging tape and then a bunch of times with cheap electrical tape. This gave the grip needed to twist it open. It still wasn't fun though. Just look at all that thread lock. Bad Olight! Bad! Dont they know that there are people out there that want to turn their lights into literal "torches" and burn little kids fingers and start fires and stuf? Some people are just ignorant i guess...
Now that its open, lets "Get this party started".
The stock driver is beautiful but not up to the task so it will be unashamedly stripped of all but the charging circuit. Charging circuits are becoming a must for me. Before I do the stripping I want to make sure everything else goes ok first. I started by making a retaining ring for the new driver. It's a 20mm TA driver, fet +7+1. It will be running the latest Narsil with three channels and I'm still trying to think of a way to use an indicator led. The stock driver was located in the battery side of the body. The new design will not allow for this without twisting the led wires much more than I want to. The charging circuit will remain in the battery tube but the driver will be attached to the bottom of the head. Contact will he made by filing off the anodizing so the battery tube will be able to screw onto a contact plate and make the negative connection. The positive will be connected via a contact plate on a spring, bypassed spring of course.
Edit: May 2, 2017
I needed some copper to make an adaptor for the driver. It will serve as the bat- connection and as a heatsink for the driver. The xpl2.2 is a new generation led and has a very low vf. This will cause a lot of heat over the regulators on mid modes and to the fet on high modes. The only copper i had and the cheapest source either way, was a 5' piece of 1" household water line. I cut off a piece about 6" long. I used a dremel with a fiberglass cutting wheel to cut a slit down the length of the tube.
Now i get to play with fire. Hehe... I lit up the torch til the copper was glowing cherry red and then cooled it with water. I am always amazed at how soft and easy to work with the copper becomes after doing this. All it took was a 3/4" aluminum rod and a block of cedar to roll the tube out flat. It always has some waves in it but i can usually get it flat enough for sanding to finish the job. After rolling out the copper, I layed out some circles using the brass pill. It fit in the grove above the shelf and in the grove below so i know it would get me close to the right diameter for my spacers.
I used scissors to cut out two spacers this size and one that will span all the way to the edge of the head where the battery tube screws up. It will make contact there after sanding the anodization off the end of the bat tube.
A step bit with the copper clamped to a block of wood took care of the central hole. But of course it took some filing to fine tune and clean it up.
I soldered the two smaller spacers together using solder paste and just my iron. Capton tape was used to protect the driver shelf from solder.
Edit: May 8, 2017
I decided to take a break from driver fabrication to get a look at the tailcap assembly.
It was quite a task to gut it out without wrecking the thing. To get it open, I fit a mini screwdriver behind each tab and bent it back just a bit being careful not to deform it. When fitting back into place I don't want it to look like a crumpled soda can.
On the back of the contact plate is a central spring that allows the assembly to spin when screwing on the tailcap.
Here it is completely disassembled. The contact plate is sturdy and poured with a conductive layer that completely covered both sides.
I removed the springs and prepared the board for triple by-pass surgery. 
Edit: June 12, 2017
Ive been jumping around on this mod quite a bit. I did a little bit more to the driver adapter but i keep hoping for a way to use the xhp50.2 in this light instead of the xpl2. However, unless i want to spend $20 on a mtn buck driver, i do not see a solution that would make me happy. I keep holding off just in case but ill have to move on sooner or later :-)
So... i decided to beef up the pill in the mean time. I added some copper to extend the pill up till it meets with the reflector. It fits tight to the wall of the host for good heat transfer. It touches the reflector for a bit more thermal mass. The walls of the host around the pill area are tapered so it was a bit more challenging than creating a cylinder out of copper. It doesn't look the prettiest but i think it will work well.
EDIT: August 18, 2017
I've been moving forward with this mod. Trying to find the time to document has been difficult however, I have been taking pictures and I've decided that rather than wait till I can do a good write up, I would go ahead and start posting some pics.
The tailcap assembly is done and I for sure decided on a three parallel connection. That means, the led of choice will have to be three colts;) XML2? XPL, XPL2 or maybe SST40... Hmm?
I managed to pound out the dents and bend the retainer back into an acceptable shape.
The spring pads are of a small diameter so I resoldered three long and skinny springs to both fit the pads and reach out long enough to be able to use Sanyo GA cells in this light. Non-button top batteries don't fit the light and there is a mechanical reverse polarity protection around the positive contacts in the battery tube. But these longer springs and a mod to the positive contacts will allow the use of the stub-topped GA cells and keep the reverse protection at the same time. This and the fact that the GA is a top notch high capacity cell made for easy cell choice in this light.
After I soldered the tall skinny springs, I was displeased with the "tippiness" and cheap feel in my hand. So, I placed the retainer over the skinny springs to be attatched to the pcb. I then put some heafty wider springs over the top and soldered the two springs and bypass wires at the top of the spring. Double springs bypassed is more like it!
Here you see the 20awg bypass wires soldered to a small piece of 16awg wire going up through the middle of the spring. Overkill?
I was able to pry and push and patiently get the retaining ring back into the tailcap. I coated the contacts with no-ox-id and lubed the assembly with a firearms lube that I really like. There are a few chips in the ano on the tailcap threads left behind from the struggle but all in all a success!
EDIT: August 28, 2017
This was actually kind of painful! Olight makes excellent drivers and this one is no exception. Beautifully layed out, reliable, and over engineered. So i hated to strip it down, But it had to be done. I tried to make myself feel better and focus on the charging circuit that was left on the board. I identified this circuit by looking directly at the sample in the data sheet for the charger. I checked in with Richard at MTNelectronics just to be sure.
I drilled holes through the center of the three positive contact springs to accommodate another triple bypass surgery. I added a copper disk to the top of the stock brass contacts to extend it past the reverse polarity protection to make contact with the raised flattop of the Sanyo 18650GA.
This is the first step of a series of steps that could be argued unnessisary but non-the-less this is what i did. The disk is cut from some isolation board saved from a tube guitar amplifier project. It will isolate the copper disc that will bring the positive of the three cells together into one central contact.
This central contact will mate with the spring from the Texas Avenger driver.
Before i button everything back up, i need to add a wire that will carry the locator led connection. I swapped out the stock led for a deep blue led. I chose a stack of resistors(not shown) that gave a parasitic drain of under 100ua. I usually shoot for under 60, but with three batteries there should be no concern of whether or not the indicator is configured on or off.
I cut a spacer that will both keep reverspolarity and allow the use of the GA cells. I used plastic from old laptop batteries. I find this plastic handy for a lot of things so I always keep some around.
Works perfectly!
I place this module back into the battery carrier.
This ring will be cut down to size and connected to the little red wire i used for the locator/indicator led underneath the pcb.
The ring is soldered and dropped into place. It will make contact with a brass button on the driver side. I cut a filler piece out of some more laptop battery plastic and siliconed everything into place.
