Second Generation Silver Plated High Current Beryllium Copper Springs and 95+CRI SST20!

Hank's (IOS) D4S listing page is a great reference to compare how the various LED's do in a real flashlight, though it's using just TIR optics:

https://intl-outdoor.com/emisar-d4s-26650-high-power-led-flashlight-p-932.html

  • The 95+ CRI SST-20's seem to do about the same throw as XP-G2 S4's, little lower in lumens, nice upgrade in throw and CRI bump from 219C's
  • The 5000K SST-20 seems like a great compromise of excellent throw, lumens, and tint, if the lower CRI and tint is ok for you

Of course this depends on bins of the LED's used... Also what's missing is the amps these are pulling. You would assume the XP-G2's and XPL's would pull less amps.

Hi
SST-20 3000k and 4000k available ?

Please read the opening post, down there, it's accessible.


By the way, who else is noticing thread auto-subscriptions upon revisit to take a peek?

^:)

So, finally did the tests with the 3500k SST-20 vs the LH351D 4000k.

Picture of die size comparison

Tint comparison with SST-20 3500k and LH351D 4000k on similar reflectors at 1 amp.

And by god is the 4000k LH351D green compared to the 3500k GA3 SST-20!

I also got a significant throw increase by swapping in the SST-20 in my Thorfire TK15, and a nice increase in red color rendition, probably given by the lower CCT and lower duv. It’s a pure 3500k tint at 1 amp.

Nice! Thanx!!

I don't notice the green much in the LH351D's, but comparatively it could be lot more obvious. Also I got mine from Richard at MtnE - it's a P6 bin but that's all I know bout the tint.

Yeah.

Also reds look so much better.

Please add 10x SST-20 3000k to the interest list for me. Line 47 on the sheet. Thanks!

MikeMacD updated to the list.

Also, will send a PM to Britanny and djozz now :slight_smile:

So, after seeing the reports of the small springs being a bit too big sometimes, I have made some tweaks to the design:

Material: Beryllium Copper C17530 38% IACS
Spring upper diameter: 4,5mm
Spring base diameter: 6,0mm
Spring thickness: 0,8mm
Spring height: 10,5mm
Total number of coils: 5
Plating: Silver electroplating

Same thing for the large spring:

Material: Beryllium Copper C17530 38% IACS
Spring upper diameter: 6,50mm
Spring base diameter: 9mm
Spring thickness: 1,0mm
Spring height: 12,5mm
Total number of coils: 5
Plating: Silver electroplating

Those leds look really good, I look forward to trying them.

Blue, i’m happy about the spring changes. I agree the first batch was sometimes too big and sometimes just right. Even with the new dimensions the “just right” cases would still be good and not too small.

I do wonder though, instead of changing the height have you considered just removing a coil and letting them be wider spaced? Once compressed with the same number of coils the height change will not be very noticeable. However, if you keep the same height, remove a coil, then after the first compression they will be shorter w/ less material so possibly even lower resistance?

Can’t really do this without making the spring quite a bit smaller, or affecting mechanical properties.

Did the math using 4 active coils instead of 5(the ones that affect conductivity in a flashlight spring), and it would make the spring deformation much higher. Instead of being 1mm of plastic deformation, it could easily go at 3mm, or even higher theoretically.

Even the manufacturer warned me about it, and recommended me to stay with 5 active coils.

You can do this easily with a steel spring of thinner wire, but not with a 1mm thick BeCu spring wire.

TLDR: Tried already, but the real world consequences would be too great to consider changing the design too much.

For my use in lots of different lights, I do have to be conscious of clearances, because many of the stock springs will compress flat into the thickness of one coil because of the conical shape where these don't because they are more cylindrical shaped. So the stock springs could probably handle longer cells. Of course if I used inner bypasses, I sabotaged the collapsing down of the spring anyway.

Also these springs are mostly stiffer than typical stock springs I see. But of course, a lot of my lights are true "budget", UltraFire and other no name brands. For ZY-T11 clones I'm working on, I'm cutting the small springs down to reduce the height of the compressed state of the spring. Should reduce resistance as well.

Not suggesting any changes, just have to bare in mind this stuff.

Even with 3mm plastic deformation it puts it from 13mm to 10mm, which is right where most medium/large sized springs are at. I’m no expert though. I think only the large spring could afford to lose this much height though. I’m biased since I (will) have both though.

Similar issues here. I find I can typically use 1 Blue spring on either end but then I have to bypass a stock spring on the other end to make up for the size/compression differences. I can rarely use both a large and small spring together as is.

Yeah, that’s why there is going to be a second revision :slight_smile:

So, I’ve shipped all of the 3500k SST-20 GA3 J4, except for Lithium, since he/she didn’t send his payment yet

Hope you will love the LED as much as I do.

Also, here are the revised measurements again:

Material: Beryllium Copper C17530 38% IACS
Spring upper diameter: 4,25mm
Spring base diameter: 5,5mm
Spring thickness: 0,8mm
Spring height: 10,25mm
Total number of coils: 5
Plating: Silver electroplating

Same thing for the large spring:

Material: Beryllium Copper C17530 38% IACS
Spring upper diameter: 6,25mm
Spring base diameter: 9mm
Spring thickness: 1,0mm
Spring height: 12,25mm
Total number of coils: 5
Plating: Silver electroplating

Payment sent :wink:

Excellent. Will send it tomorrow.

Material: Beryllium Copper C17530 38% IACS
Spring upper diameter: 4,25mm
Spring base diameter: 5,5mm
Spring thickness: 0,8mm
Spring height: 10,50mm
Total number of coils: 5
Plating: Silver electroplating

Same thing for the large spring:

Material: Beryllium Copper C17530 38% IACS
Spring upper diameter: 5,0mm
Spring base diameter: 9mm
Spring thickness: 1,0mm
Spring height: 12,50mm
Total number of coils: 5
Plating: Silver electroplating

I dont see how keeping the coils and thickness the same will change the overall height much? Since the coils stack aren’t you just making it less springy and more stiff? The depth that it bottoms out wont change much will it?

Now that’s where the difference is.

By making the top spring diameter smaller, each coil’s diameter will get smaller as the delta h goes up, which will form a conical shape.

That will allow for higher spring compression, down to about 1,00-1,50mm, which will make battery fitment much easier.

Sorry if I’m changing the values constantly. I’m just inputting values in my calculator to see what could fit best.