OK, so it was 4AM, and like any other completely normal person, I am of course, working on a flashlight LOL. So I’ve got my EL-cheapo ebay securitying SRK in pieces before me to prepare it for It’s final transformation, which will basically be a handheld lithium fed nuclear reactor, so im looking for as little resistance as possible throughout the entire light. Now I guess I got lucky with part of this, being that on my version of the SRK the tail cap DOES NOT come off. It is one solid piece from the tail to the joint before the head, so that left only one joint to worry about and a pesky clover shaped piece of pcb in the bottom of the can. This thing was thin, flimsy, and only held down by one screw in the center, and had 4 springs soldered to it.Theres no way this is gonna fly. So I pulled the pcb and desoldered the springs, laid the pcb out on a nice 1/8”ish thick piece of solid copper I had laying here and cut it out, then I took 4 new springs and got ready to braid up some copper wire and out of the corner of my eye I spied this….
I’ve always had trouble getting the braid inside the spring and secured well. I always end up with a really stiff braid or no flex at all, so I started thinking outside the box, or in this case spring lol. At first I thought “Nice! pre made braid!” but then I thought of something else… I’ll just let the pics do the talking.
The springs are still really flexible, it was WAY easier than putting them inside, and I think it looks pretty cool! I figured as much info as I’ve gleaned here over the last months, I needed to share the little discovery I made, just in case it could make someone else’s life easier!
Is this stainless braid? Like for a oil cooler for a car? Or is it some type of conduit? Let me get this straight, you took a random spring wrapped it in this braid and just stuck it inside the tailcap/driver spring and let just chill without soldering?
the braid is nickel plated copper. It was a piece of shielded electrical wire with a few strands inside. I did solder both end after tucking the braid into the spring. I’ts just much easier to solder the ends and not get the solder all through the braid this way, so the whole thing stays flexible.
You can solder the spring to the PCB first, then pull the braid on it. It should be a bit less effective, but it circumvents the problem of the braid adsorbing solder and hardening.
Single strand of silicone covered copper wire, slightly coiled, is much easier and will last longer. The braid breaks with constant movement of replacing cells and/or sucks up solder and hardens. I’ve fixed quite a few lights with un-attached braid and strands poking out everywhere that came to me from other people. never used braid myself as it’s considered to be “solder wick” and not intended to carry current. Some of my heavy mods have 18ga wire inside the spring, mega current carrying ability! (especially when done in a through-board style where one end of the wire attaches directly to the switch and the other end is at the top of the spring in direct contact with the cell)
Dumb question, but how much improvement does bypassing the spring get you? Even with thin-gauge spring wire, the sub-inch length should still be measured in milliohms. Unless you’re building a shelf-queen that pushes 10A through an LED and has a runtime of like 10min, would bypassing the spring make that much of a diff?
Hell, lookit the thinness of the bond wires in the LED!
Well for one, the actual length of the wire in the spring is much longer. Also lots of people EDC lights pushing well over 10A; high power does not a shelf queen make. Less resistance is almost always a good thing, though it may not always be necessary for the desired results. In general if a light will be doing 2.8A or more, I bypass the springs. Will it make “that much of a diff” under 4amps? No, but there’s no reason to not do it either
Over 6A the spring can heat up and collapse, breaking cell contact and rendering your light useless. I usually bypass at 5A and above in a single emitter (3V) and all triples/quads get the bypass.
My EDC triple uses an 18350 and pulls over 7.15A. I wear it on my person literally every day and use it sometimes multiple times a day, even before nightfall. Shelf queen? All my high power lights were modified for a purpose, they all stand ready with charged cells and get used on a regular basis.
I have no intention of being out there in the night and having a spring collapse, leaving me in the dark when I’m trying to do something.
Aha, okay, I get it. True, pushing multiamps through a thin spring would turn it into into a toaster.
I guess I’m coming from a different place altogether. My idea of an edc would be having multi-hour (or at least *1*hr!) runtime, so 2.8A from a decent cell, max. I almost hesitate to ask what you do that you need 7A from an edc light!
Criminy, I didn’t know an 18350 could do even close to 7A…
I imagine unprotected?
But see? That’s where I’m coming from. Limit current to the/each LED to a manageable level, use protected cells so it doesn’t go supernova and turn my edc into a pipebomb (yeah, I did once manage to turn on my edc right through its nice Jetbeam holster by bumping it on an armrest when sitting down, only to discover it much later when it was acting like a rather nice hand-warmer), and just in general keeping things all around to a manageable level (ie, trying to minimise the weakest link).
When talking about reliability as far as the spring, understood, as I kinda go for reliable, too, on both a system and component level. Yeah, can’t hurt…
An no disrespect to anyone calling a high-amps light a shelf-queen. To me (again, just where I’m coming from), I need to have some decent runtime for an actual edc. I’ve been through power-outages where I needed decent light for about an hour or more, so that’s always been a personal requirement. I tend to like 1-mode lights, so I (try to) pick a balance between lumens and runtime. And that kinda rules out DD in favor of a bunch of 7135s regulating the current.
At first I thought “Nice! pre made braid!” but then I thought of something else… I’ll just let the pics do the talking.
(especially when done in a through-board style where one end of the wire attaches directly to the switch and the other end is at the top of the spring in direct contact with the cell)
