BLF Interest List: EX3 High Current Beryllium Copper Silver Plated springs - Still selling my springs :)

Hello again.

Third time’s the charm, right?

I’ve been preparing and designing the 3rd Rev BLF BeCu spring nicknamed “Blue Spring”.

The 1st gen was a plain BeCu C17530 nickel plated spring.
The 2nd gen was a silver plated BeCu spring.

The 3rd gen is where it gets special, and we get into some exotic designs.

We couldn’t really bump up performance by changing the material, because that would make the mechanical properties way worse.
Couldn’t remove a coil, as that would worsen plastic(permanent) deformation.

So, I decided to turn to electroplated copper! By putting a thick layer of copper(20um+), we can increase the conductivity of the spring significantly without messing with the wire thickness/mechanical properties, and get a huge relative boost in conductivity, of about 20–25 compared to the other springs!

Here are the springs’ specs:

Large spring:

Spring upper diameter: 6,25mm
Spring base diameter: 9mm
Spring thickness: 1,0mm
Spring height: 12mm
Total number of coils: 5
Plating: Copper + Silver electroplating

Small spring:

Spring upper diameter: 4,20mm
Spring base diameter: 5,75mm
Spring thickness: 0,8mm
Spring height: 10,5mm
Total number of coils: 5
Plating: Copper+ Silver electroplating

A pic of the springs, courtesy of Kit Latura:

And my work with it on a modded BLF Q8 tail cap:

And in a BLF GT Mini:

Oh boy, these can sustain some very high currents of 20A+!
Some of our top modders(DB Custom) put them in his Sofirn Q8 458 HAM’R, and he didn’t even need bypasses to get 21A out of each Honestly, even I wasn’t expecting them to be this good. :slight_smile:

And other notable advantages:

1. Stupid easy solderability. As quoted by DB Custom and contactr, these springs are so easy to solder to it makes it tempting to use spring bypasses with them, which was surprising.
2. High stiffness. Allows the use of short 18650/26650/21700 cells in series. Very nice.
3. No more need for bypasses with dual BeCu springs for 99% of the time.

I’m also going to be making some budget phosphor bronze springs, so express your interest below

Also, best piece of the bunch!

You know about the nice SST-20 4000k 95CRI? It’s a great LED and all, but tint on low modes is sometimes… not optimal for our flashaholics’ eyes.

So, me and Texas Ace got our hands on a supplier that supplies FD2 below BBL SST-20s 4000k!
So finally we won’t have to use XP-L HIs to get good throw and good tint.
We’ll have the best jack of all trades: super throw, super color rendition, and great tint!

I need 500pcs to make the order, and they may be gone quickly, so sign up quickly to get some rare unicorns that make come now, or much later.
I want to help the community as much as possible to get the best things as possible, so this is a very nice thing to happen to us!

Prices for every GB item:

3rd Gen BeCu springs: 0,46$US/pcs

*_+SST-20 4000k 95CRI FD2 LEDs: TBD after the main GB is done(GB: 1,55$US/each for less than 10pcs, and 1,50$US for more than 10pcs)


Shipping: 5,00$US internationally.
No tracking unless you spring at an extra for tracked shipping in the Canada/US.
Nothing else really for Europe.

Link to current interest sheet:

UPDATE 1POST 147: BLF Interest List: EX3 High Current Beryllium Copper Silver Plated springs - Still selling my springs :) - #147 by BlueSwordM

UPDATE 2 POST 203: BLF Interest List: EX3 High Current Beryllium Copper Silver Plated springs - Still selling my springs :) - #203 by BlueSwordM


Ok guys.

So, I’ve finally shipped to everyone who has paid and responded on Friday, which is nice.

Anyway, I’ve messaged people on Wednesday who still haven’t responded and paid about their LED orders, so will wait until Wednesday.

If the people messaged do not respond before Wednesday morning, I will have some LEDs left.

So, since there still seems to be some demand for the FD2s*, I’ll sell them to the people wanting below(will PM them on Wednesday) with their spring order too

1. likevii: 20x of each size BeCu 3rd Gen spring + 3/8 SST-20s FD2*
2. Lund1660: x SST-20s FD2*
3. KevinZA1988: x SST-20s FD2*
4. contactcr: 10x large and 10x small 3rd Gen BeCu springs

*Orders with SST-20s

Now, onto the more important stuff.

We are at 250pcs for the SST-20 4000k 95CRI FD2 LEDs.

Remember that we need 500pcs to make an order, and that it may come and go quickly.

Are you able to get samples to test? I’m just a little wary because FD2 was only at the BBL after 3A in maukka’s previous tests.

Interested in 10 each of the third gen large and small springs and 5 of the sst-20

Did you measure resistance? How much did it improve over 1.0 or 2.0?
Also, could you clarify:
Is it 0.8 mm wire which is then plated (for the small spring) or a 0.76 mm wire which comes out as 0.8 mm after plating?

I calculated the first case by treating both layers as parallel conductors (which I suspect is not perfect) and came out with:
632 kOhm/m plated, 728 kOhm/m raw spring of the same thickness (0.84 mm). So 13% improvement in resistance for the small spring compared to unplated but thicker (which is not directly comparable to 1.0 or 2.0).
For the big spring that would be 423 and 475 kOhm/m respectively, 11% improvement.

If this is correct - I think this is a good improvement but I wouldn’t call it “huge”.

This came around quicker than expected, you musta been working hard!
Can’t edit the spreadsheet so can you add me in for:

10 large Mk3 springs
10 small Mk3 springs
20 budget springs
10 FD2s

please :slight_smile:

I’m down for 10SST-20 4000k 95CRI FD2

Sent request to be able to edit the spreadsheet.

Or just add 30 x SST20 FD2 to the spreadsheet for me.

Thanks for making this possible!

Put me down for 18 x SST-20 FD2 please.

Are the rosy 3000K’s available btw?

im in for 15 x SST-20

Add to my 10 FD2 (line 13 in new list) 20 large and 20 small 3rd gen springs.

It looks like, according to the chart you posted, the FD2 tint bin actually spans across the BBL, so individual samples may be above or below the BBL.

Clearly that just means people should order extras, both to fill the MOQ faster and so they're more likely to get enough under the BBL ;)

Ok guys, sorry for some of you, but added the shipping.

Also, @Bob_McBob, they are the same LEDs as what maukka’s tested.
So quite a bit better than what we had before, but not FA3 levels of improvement.

@Agro, that’s 0,8mm+0,040mm in this case, since the 20um figure is only in terms of radius, or one side plating.
So, the total plating thickness is 40um.
Also, the nice thing about plating is that it’s like a cold weld if done well. You can treat those as parallel conductors.

Also, here’s how I calculated the improvement:
Let’s take the large BeCu spring with a 25um copper plating(0,050mm total diameter).
Since copper is 2,6 times more conductive than BeCu C17530, it’s a virtual 0,13mm increase in total wire thickness, so a virtual wire thickness of 1,13mm.

By going with the same calculations, the spring would actually become 20–25 more conductive!
That means the resistance would go down from 9mOhms down to 7,5mOhms-7,2mOhms, without losing the good mechanical properties which were sacrificed in the 2nd gen spring by removing a coil.
So, compared to the 1st gen spring with the same mechanical properties, it’s actually a great improvement.
I still wonder why I didn’t think of that the 1st time around…

Anyway, the improvement is quite a bit larger than what you calculated, so that’s nice.
Finally, the last improvement we could do is a gold plating, but I’m going to keep it for the Ultimate spring, since it’s so expensive, especially with a copper undercoating.

All have been added to the list:

We are at 328 SST-20s FD2 LEDs!

Only 162 more to go.

Which direction will the springs be wound?

I got 100 of the 2nd gen springs and my complaint about them is that they’re wound in a way that’s causing them to gouge into the ends of the battery as you tighten down the tail of the light.

Stronger springs will only gouge deeper if they’re wound the same direction. If possible can they be wound the other way or atleast have the small end hooked in sharply in for battery protection?

Yeah, that’s why I’m going with the 1st gen spring design as found in the photo.

I’ve had the same problem, so going back to that 1st gen spring top coil design.

Added back again with some corrections:

I can’t edit the spreadsheet, please add me in for :

5 x large springs 3
5 x small springs 3
10 x budget springs
10 x SST-20

Thank you :)

BlueSwordM, why do you think Gold would be an improvement? I thought Silver was a better conductor than Gold. In what way does Gold improve the spring?

Added to the list:

Again with the mistakes…

@DavidEF, gold would actually be an improvement in contact resistance because of its atomic structure.

That’s a thing I discovered at my new electroplating job: the reason gold is used in contacts is that its contact resistance is extremely low due to its atomic structure allowing a form of cold weld happening, reducing contact resistance by a huge margin.

It’s about as good as a soldered connection, or slightly better at times due to much thinner layer of contact.

This prevents the formation of hotspots, which is very important in small contacts like we have, as this would increase resistance, and therefore heat.

TLDR: In terms of lowest contact resistance:
Absolute best: Gold.
Excellent: Silver
Good: Silver tarnish.
Good: Nickel
Good: Pure copper
Absolute crap: Oxidized copper.