I did a quick conductivity test on one of your springs long ago, injecting a high current over it with my precision power supply and measuring the voltage drop over its opposite ends as best as I could; I also tested one of the springs coming in one of the Convoy SST40 drivers, and couldn't find a significant difference. It was a quick test, and can't say if I did it with a gen2 or gen3 spring.
Your efforts are welcome in any case. Concerning the idea behind copper clad steel, or what I have in my mind, is some ≈70% O:) IACS, copper clad piano wire :-D spring with a decent plating. And of course, springs made with thick and short in lenght wire, for maximum conductivity.
I did that the other day and I got ~9mΩ for both small and large springs, Intl-outdoor about 4mΩ but they are significantly shorter, which makes sense because their lights don’t accommodate for protected cells, they also put a thin brass button under the spring to prevent the cell from crushing the components on the spring side of the driver.
@thefreeman, that sounds about right taking into account contact resistance.
I’m still not going to go with gold plating as I got a new quote, and the prices are still as expensive as ever, and I don’t want to increase the prices yet again unless I can massively increase the current performance of my springs.
My measurements don’t account for contact resistance, I used a four wires measurement with the voltage probes at the end of the first turn (bottom and top)
A 1cm piece of 22AWG is only ~0.5mΩ, significantly lower than the measurements of the springs I posted just above (though it’s uncompressed, if the spires touch it could be lower)
Spring bypass is in general terms always better. However, and despite the above figure from the freeman is accurate (“1cm piece of 22AWG is only ~0.5mΩ”, 544.381µΩ or 0.544381mΩ according to Electrodoc software), it must also be noted that a proper spring bypass needs to be coiled, or else its life could be rather short. If the bypass is not coiled, it will elbow at some point due to the spring compression, and after repeated spring compression and release it will sooner or later crack at the elbow joint. For this reason the lenght of a proper spring bypass must also take coiling into account. It is only slightly more lenght versus straight wire, 30 - 40% maybe. Cylindrical toothpics make good molds for coiling the wire, by the way.
Properly coiled spring bypasses can last for ages (the solder points are critical and must be done properly).
Silver or gold plated copper clad steel, please. O:)
And please, believe yourself attaining superb springs; with a really high IACS number and thick short prings, you can go much further than before.
“Thick and short” matters, as the lesser lenght in the spring wire means less voltage drop, while some extra thickness compensates for less spring coil turns while reducing voltage drop even more and increasing overall conductivity.