Updated.

@Barkuti again, thank you. I will add the Fasttech Carobronze spring info on the OP.

Edit: I have also added the small springs measurements.

Edit 2: Spreadsheet has been updated.

We are at 812 big springs at 257 small springs.

I will ask the manufacturer if it is possible to make 1000 big springs, and 500 small springs. So we can get all of our springs at the same time

Well, this is what I am probably going to do once I receive my testing samples and test the voltage drop at 6A.

You’re welcome skinny_tie.

I do wonder though.

Why did Hank not make a bigger beryllium copper spring? He must know about the demand, no? Or does he think the spring would not sell well?

Or maybe it is just because that at the time the small beryllium copper spring was introduced, there were almost no lights which could take advanatge of their very low resistance except for the Noctigon Meteor?

Or maybe he did just think there was no market for a bigger spring.

Edit: There are a total of 841 big springs and 277 small springs.

If the small springs reach 500-600 springs, I will ping the manufacturer to make a batch of 1000 springs.

The group buy will continue for 3 weeks.

Is there something you guys think I should change about the big spring?

Would you prefer a gold plating instead, and a 1.1-1.2mm wire for even better conductivity? Or a smaller top?

Let me know.

Yeah I don’t think it is worth it for the additional cost

I will ask if it is possible to use 1.2mm wire for the same cost or not. I don’t think it is going to cost more, if it will cost more at all.

At 1.2mm diameter though, that is going to be one tough spring.

With a 1mm wire diameter, it is better than a 23AWG wire, and a bit less than 22AWG wire.

With a 1.1mm wire diameter though, it is about as good as 22AWG wire.

With a 1.2mm wire diameter, almost as good as 21AWG wire.

So no need for a bypass for once with these springs.

I personally don’t like doing spring bypasses on steel springs. They just suck too much solder, and tend to fail if you don’t have enough experience.

Thicker is always better when resistance is concerned at such high currents we do(10A+).

However, there are design limitations in the case of a compression spring for a battery, mostly memory elasticity.

From the info I have gathered, 1,3mm is probably the limit, but a bit thinner for more room for elasticity is needed. So 1.2mm will probably be what I pick if there is a small cost difference, if any since I’m ordering more than a 1000pcs.

OK then.

I will keep the spring thickness at 1mm.

I knew something would be wrong if we increased the wire thickness. Thanks for confirming my doubts djozz

List updated.

We are at 961 big springs, and 407 small springs.

Since there are so many people wanting small springs too, I will now inform the manufacturer to make a batch of smaller spring with these dimensions along with the big springs:

- Spring top diameter: 4,5mm

- Spring bottom diameter: 5mm

- Spring thickness: 0,8mm

- Spring height: 8mm

- Plating: Zinc plating

Doing this allows for lower shipping costs and lower bulk costs per spring.

If anyone wants to change something about these dimensions above, say it to me.

Thanks again for the community.

The manufacturer has said that while it is possible to make 1.2mm wire without a cost increase, making a 1.1 mm is not directly available without a cost increase, so I will keep the thickness to 1mm as initially said, and corrected by djozz, as 1.2mm is too thick and will hurt memory elasticity and may make the spring collapse under a cell.

No limit. 1000pcs is just the minimum order. The more spring we can get manufactured though, the lower the price per spring will be.

Bulk purchases really help getting the cost down by a huge factor.

List has been updated.

One other thing: would you prefer better spring mechanical properties using Beryllium Copper 38% IACS C17530, or slightly better conductivity using Beryllium Copper 45% IACS C17510?
I would like to know your choices.