Large BP Spring:
Material choices: BeCu C17200/Phosphor bronze C54400
Spring upper diameter: 6,00mm
Spring base diameter: 9mm
Spring thickness: 1,0mm
Spring height: 13,00mm
Total number of coils: 5
Plating: Copper(50um)+Nickel
The main advantage of using phosphor bronze would be much lower cost, with 1/2 the conductivity of BeCu C17530 and slightly better mechanical properties.
The main advantage of using BeCu C17200 would better mechanical properties by a nice margin, at a slightly lower price than BeCu C17530.
@djozz, why would you want a lower performing(electrically) spring?
Do you plan on using those as a support for a bypass if it ever fails?
Just because I know that when going budget, the electrical performance would go down anyway, it was a way of saying that it is not a big problem to me. Reason is that many of my current favourite leds are so low voltage that maximum spring conductivity is not important anymore, 3 times better than steel is way sufficient.
BlueSword, I apologize if you’re already aware of the latest in the FW3A emitter choice saga, but just in case your experience looking for good bins of SST-20’s can be helpful to that team, you might check out Toykeeper’s latest update in that thread:
Yeah, the last time they broke a piece of special glass with Be, a team came to decontaminate the room.
Imagine I lend or sell my Q8 with BeCu copper springs, the guy remove the battery, put it back but with one battery reversed = short and then one spring goes “poof”…magic powder. No thanks.
I don’t want to have to keep track of which of my flashlights have BeCu springs. I’m fine with springs bypass or springs with a tad higher resistance. I don’t seek maximum lumens anyway.
The risk is negligible, especially since the springs have much higher conductivity, but a 0,0001% risk still does exist.
Still, in a dual spring array, I’m always worried what would happen to the cell inside of a light that would be shorted. A dual spring setup will not fail easily in a short, especially if compressed.
I’m more worried about a cell catching fire than BeCu finding its way into the air.
The day someone manages to vaporize a BeCu spring, they’ll just tell me.
BTW, copper powder is still very harmful if inhaled or blown up, as copper oxide power is quite reactive.
What will the price be on the lower performance small springs? I need 30, not sure the price savings vs. just going with the regular HP BeCu ones in the original post?