Building a Dual Parallel Unregulated 26650XL in a Billet 1590B

[kaotikgood]

I'm highly experienced in miniature and microminiature electronics building, repair and replacement.

Just wanted some feedback on hardline connections, ie >/=16AWG solid core unshielded copper. This stuff, in my experience is hard enough to build a heat bridge for eutectic solder, let alone lead free.

Are you guys arc soldering? If not what temp are you running you iron at?

Are you using Tin/SIlver and Copper Solder or just Tin/Silver?

Pre-forming wire runs or solder as you go?

Basically any good or bad experiences would be interesting to hear about.

Kind Regards,

johnny(kG)

 

[dc99]

I use 63/37 tin/lead rosin core. Rarely go past 650 on the solder station. I don't really like the solid wire. Its a pain to work with for me. I prefer silicone jacketed wire. Hobbyking is a pretty good place for it. I like to solder as I go as it seems to be less waist of wire.

 

[Mooch]

I'm also using the 63/37. I'm using an OKI PS-900 iron so no temperature setting. It heats up until the solder melts and then backs off the power....incredible difference in how I solder. Everything from 32AWG to 6oz copper PCB ground planes without having to change a setting. Expensive though but I needed it for work.

For larger gauge wires, 16AWG-2AWG, I usually use a flux pen on the strands/strand first then tin the wire. I'll also flux and tin the contact too. It makes it a lot easier to bring the two together without overheating anything. If I need to wrap a wire around a contact I'll flux the two, connect them, and then solder. I don't use 2AWG wire in a box, of course, but on other stuff I have.

I've found that with standard temp-controlled irons that wattage is a lot more important than temperature. Larger gauge wires pull a lot of heat away so you need a higher wattage iron to keep up and hold the temperature steady. Just raising temperature, on an underpowered iron for the job, just leads to burning stuff. With a higher wattage iron you can use a lower temperature but still heat things up a lot quicker. The PS-900 is 60W but I use it for everything from 0402-sized passives and TSSOP chip surface mount stuff up to 2AWG wire. Need to swap tips for that, but that only takes about 3-4 seconds.

I like the silicone insulated wire too. Larger diameter but easy to strip and handles soldering heat well...important when soldering the larger gauges. I'll preform/cut/flux/tin the wires first, making sure everything fits well, before soldering everything in. But, I like neat wiring. Very handy when something breaks later and I need to try to remember what goes where. Having multiple colors helps a lot too...red for POS, green for GND, and black and white for other stuff or data. For silicone wire, just black and white.

 

[kaotikgood]

i thought that lead free would be a must. no issues then using 63/37 i'm assuming?

 

[Mooch]

63/37 is great, easily the best alloy to work with when soldering. Superior wetting, quicker solid-to-liquid transition than 60/40, and lower melting point than SAC305 (my usual lead free alloy) makes it a joy to use. But, the lead is an issue, especially in the EU.

I always use lead free when doing (low volume) production work for my clients as most of them must have everything be RoHS compliant. But for myself and for some prototype work the better wetting I get with leaded 63/37 just makes things a whole lot easier.

I also use 63/37 for anything undergoing severe thermal cycling as it handles this much better than the lead free alloys.

 

[kaotikgood]

Good to know. I always prefer eutectic 63/37 because of the lack of a "plastic" state transition. I was planning the build around 100% lead free and using tin/silver/copper and arc soldering. I like the speed t which it works and lack of prolonged conduction heating. Since it is an unregulated box I figured I'd be able to get away with this method.

 

[batteredwombat]

I have seen pictures of mods with sold copper wire. I used a 40w solder gun 63/37 and just melt stuff lol. Always wondered how lead free is and would like to use for next project but heard it is a major PITA to work with.

 

[kaotikgood]

[In my experience] lead free is drastically more effective with really well done tinning (not that any form of soldering isn't, just more evident with it). To me that means, get a solder pot. You can get a cheap one online for a single job, or drop a little chunk and get one that will last you for years. This makes tinning everything from hook up wire leads to battery sled contacts so easy. Since PBfree, whether it is SnAg, SnAgCu or any other, has a plastic transition state..wetting can sometimes come at the price of heat conduction damage from length of exposure. Solder pot keeps it all nice and fully liquid...just mind your slag