Spring bypass magnetic tailcap

For sofirn/wurkoss lights that have that big chunk of magnet in a hole in the center of the tailcap surrounded by aluminum.

The spring rests right on top of the magnet, kind of in that hole where the magnet is. The diameter of the base of the spring is the same diameter as the magnet and is sort of snug in the same hole. Right? You know what I’m talking about.

So the electrical connection obviously isn’t through the magnet it’s where the perimeter of the base of the spring contacts the aluminum perimeter of that little hole the thing is squeezed into, on top of the magnet.

So for a spring bypass or if you want to add a double spring what do you do so it fits back in that little hole and it’s secure, when all you can solder to is the spring itself? Cuz the rest is just aluminum and magnet. Just run a wire down the inside of the spring with just a lil solder and squeeze it back into the hole? Do you use some crazy glue somewhere? I feel like I can never get the spring back in just right like it’s just sitting on top of the magnet and it was held in place better before.

Maybe I’m overthinking this.

It’s tricky to get those round-bottom springs back in there sometimes…I had a heck of a time with the small one in the SP10 Pro. If you have a suitable piece of tubing, you can cram the spring in one end and use a pusher to poke it into the recess…the suitable tubing is the hard part. Springs with the triangular bases are easier to deal with.

On spring bypasses, those seem to have fallen out of favor. Most lights are using much better springs these days and most drivers aren’t really letting a ton of current through (although a bit more than in the past), so the bypass won’t gain much. Sofirn used to do it on a few lights and then stopped, although that may have had more to do with poor soldering and/or complaining customers when the bypasses would eventually break (as they will). For this, I think I’d just try to glob it on and perhaps smooth with a file before reassembly, maybe attaching the bypass wire to the opposite side of the bottom coil where the cut end is…that way you can still manipulate it for insertion without stressing the solder point. Bypasses were more valuable with older cells that had more IR and especially with lights that used mechanical tail switches. The move toward solid post + contacts on the driver sort of negated the need for bypasses on that end.

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I only ask because I cooked the spring on my Wurkoss ts25 or something, caused the gold colored coating to flake off it. It’s a decently thick spring too. I kept using it but the loose flakes got stuck in the grease on the threads and were causing little miny zaps when I was screwing in the tailcap. Weirdest thing. Figured probably don’t want those little flakes to end up in the wrong spot.
So the spring has to be replaced anyways. And they don’t sell the tailcaps individually.

I’ve got a little bag of much thinner gauge springs from convoy, half the size, but if I stretch them out and double or triple them up they seem like they look like they should work.

The original spring was actually pretty solid idk how much current this pulls but it’s alot. I would measure it but I cooked my backup multimeter today. Half welded the probes to the terminals on a car battery trying to measure volts with the probe still plugged into the amps port. And the other one has a blown fuse. Safety!

Maybe try to PM @BlueSwordM to see if he has any of his springs to sell. I bought some of those a while back BeCU silver plated (? IIRC). He tested them as having less resistance than “regular” springs bypassed. I have been using them to double up springs in some lights.
They work very well.

I’d ask Wurkkos if they would just send you a spring…that sounds like faulty plating to me. Or make them send you a tailcap.
They can do it if they want to. They may balk a little if it’s not tossed into another order. That’s weird about zaps but yeah, definitely don’t want conductive flakes ending up somewhere they could matter. Kaidomain (or their sister site on ali, LHT Flashlight Store) have loads of springs and they all seem to be pretty good quality. Usually under heat/pressure a stretched spring will find its way back to the original height or close, but doubling would work fine. I don’t have this light but should be receiving one in the next few days…seems like a review said that it was pulling way more amps on turbo than I would have expected, but it’s enough that you probably should use a clamp meter instead of a DMM (for accuracy if nothing else, but the 10A setting on most meters should be respected…some will go over and some won’t quite reach that level, if the leads are even worthy enough). The small Uni-T 210E clamp meter is a nice standout, one of the few that will do low-amp DC measuring…usually in the $55 range but if you’re patient sometimes coupons get it down to $45 or so on amazon (can buy direct from aliexpress, too, but this is an item that I prefer to have easier returns with if something is awry). Pretty handy and decent meter, handles the majority of typical electrical work as well.

The last meter I got (EEVBlog…a Brymen model from Taiwan) has a “beep jack” feature to keep you from doing the oops like that. It can be a little irritating at times if you’re switching between functions a lot but it’ll sure warn you if your leads are in the wrong port for the function on the dial! I don’t know if any of the cheaper units these days have that but I guess it’s not uncommon on higher end meters. Hope you didn’t see fireworks…! :slight_smile:

Ya that’s probably what I’m going to do. It only got damaged when I put a Molicel in it. Stick to the cell it comes with you’d probably be ok.

If I can find a fuse I’ll tell you how many amps it is at the tailcap at least. My one DMM says it goes to 20A. It’s like 10 years old, idk if they make ones that go that high anymore or if it’s safe to use but it says it is. I don’t remember blowing that fuse either, I think it just died of old age. THAT meter wouldve been beeping like crazy if it was in the wrong setting, but I was using my little pocket sized extech as a backup that doesnt beep but really should because it’s not a super cheap meter either. I haven’t opened that one up yet but I’m pretty sure it’s fried just based on the smoke lol.

When I go get a new car battery I’ll get another meter I’ve been meaning to anyways.