.1mm stainless steel with .2mm copper and no flux work? Thinking I’ll try it with my Amazon welder
https://www.amazon.com/gp/aw/d/B0DCBVB8XF?psc=1&ref=ppx_pop_mob_b_asin_title
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@SternWake thank you for that testing buddy.
I will try with the AWithZ UF20B to see what I can archive.
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I will try 0.2mm copper, 0.1mm stainless no flux, this evening.
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I lowered it to 1 pulse and no preheating.
Gear 550 = ~ 55% of the available power
0.2mm copper under 0.1mm Stainless steel
No flux.
Couldn’t pull it off, had to use needle nose and roll it off.
Vey strong weld.
This P20B welder says 1625 amp output current max, at 9vDC, 14.6kw
Your Amazon welder says 2000 amp output max and one reviewer said it charged to 5vDC, so 10 kw.
14.6 x 0.55 = 8.03 Kw
It seems your welder should be able to weld 0.2mm copper under 0.1mm stainless steel, without flux at around 80% of max power.
I saw 0.08 and 0.05mm stainless steel for sale on Ebay.
Good luck, let us know if it works
The AwithZ UF20b is 10.x kW and one of Nelvick’s clients said he could weld 0.3mm copper under 0.1 mm stainless, and I assume that is with flux, but perhaps not.
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This is my subscriber that has a channel as well. He is very skilled.
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I’ve got plans to make some smaller high amperage packs and once my supplies get here putting some test pieces together for mooch to mess with.
A direct comparison of two packs - one with nickel and one with copper would be cool but i don’t have the resources to pull that off. Id be willing to make something i just don’t have that kinda cash flow in this economy 
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@Pecos Tell me what you need. I can sponsor you.
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How about two small 10s1p packs made from tabless cells. One uses 0.2copper, the other 0.2 nickel. Adjust vesc settings down for 10s and battery amps down to the max CDR of cell chosen.
The batteries would be worked hard in a board used to 12s6p or greater and the differences obvious even without data logs.
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Why not just measure the electrical resistance of the packs?
I guess because Jackson wants to understand if there is any noticeable difference in performance.
I’d personally prefer to have less resistance across the pack and just use copper, but as a builder who somewhat pushed the limits of 0.15 nickel on numerous occasions to zero failures, I’m sceptical that there will be any noticeable difference on ride logs alone
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Resistance = less voltage making it to ESC, and more of the cell’s energy going to heat the conductors, rather than to the ESC, and motors.
For me it’s not just about what temperatures the cells, interconnects, ESC and enclosure can safely tolerate, it is about whether the interconnects are a heat source, or a heat sink, and getting the maximum voltage possible, within reason, to the ESC.
Keep your stinking 0.15mm nickel away from my tabless cells!
I can weld 0.35mm copper.
Try and stop me!
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Welder arrived today! Thanks @DIY500AMP.COM ! Gonna start playing around and see what i can do
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I glad arrive buddy!! Enjoy the beast!!!
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Beast is correct, was trying to set it to weld .2 nickel to kinda establish a baseline for what my kweld does and im used to. it absolutely nailed the strip down at 050 with 10ms preheat.
Without caution this could easily put way too much energy into a weld. I will be proceeding carefully
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For 0.2 probably you need to go with 030 or less, 0.10 pre-heat 2ms dual shot.
Another difference is you need to press firm.
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Keeping the pressure constant after having the kweld is a relearning process. The kweld automatically adjusting the output energy to the weld material resistance is a feature i already miss… but then i just welded .3mm nickel quite nicely and the probes are still cool 
Getting my feel for welding pressure back from when i was using my modified red pcb $20 welder. Definitely want to try silicon bronze tips for durability on this though - the soft copper tips easily lose material into the weld and i don’t think they need to. Ill check the local welding supply and see if they have some rod i can cut to shape eventually - though ive got lots of tips to test with for a bit
My 21$ purple spot welder required I press firmly to compress the sandwich to the cell, and then let off by half or so, to get a good weld. Holding the same pressure led to weak welds. My red one was the same way. The purple one proved stronger on same weld battery so I refined my technique with it.
I am basically using the same downward pressure I used on the purple welder to compress, but keeping that pressure when I press the pedal.
I tried more and less pressure and it did not seem to make much, if any difference, so I continued to just use that same firm pressure and tried to be consistent with the AwithZ p20b 14.6kW
model as I was working my way up the gears in 40-50 steps
I think casual readers if not already aware should know that Pecos has a higher power Model welder p60C? than me, and the gear he uses is likely equivalent to Double the power of my welder on the same gear, And Nelvick has the Mack Daddy P120D which is something crazy like 69 kW of power and Double that of Peco’s. If his is the 29.2kW p60C.
Don’t hold me to these exact numbers.
My 1.5mm x 15mm copper braid came today, and in my grubby paws is much different than expected.
My thought was If copper to copper welding is possible, how about eliminating solder, and the wicking and potential brittleness and the significant amount of heating the cell must endure when soldering braid to the tabs.
So I cut a strip of 0.15mm copper, squeezed some flux into the braid top and bottom and sandwiched it.
5 pairs of welds each side, no preheating, single pulse, gear 550.
When I pulled it apart, I realized the flat copper braid is basically hollow sleeve.
The stranding in direct contact with the welds is certainly welded firmly.
I closed up this test piece, and positioned my electrodes on Either side of the 0.15mm copper, I didn’t add any more flux.
Added 0.15ms preheating, single pulse, gear 550, and hit the pedal three separate times in total after repositioning the electrodes.
I didn’t pull very hard, but it did not want to come apart very easily.
I obviously didn’t nail the technique or settings, but as far as proof of concept, I don’t think it can be ruled out.
The opposition welds did not make much if any flux smoke compared to the 6 pairs on each side of the 0.15mm so it was probably ineffective on the opposition welds
However I don’t have my HEPA filter set up properly to capture the smoke and do not wish to experiment with this more until I do. Also, the 1.5mm x 15mm braid seems quite excessive.
I have no experience with braid.
I assumed it was all flat, but mine is like an expandable sleeve.
I have some more ideas to try, but I think wide flat Braid and no solder flexible series connections should be possible
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In my experience, all braid is a flattened (expandable) tube/sleeve. This allows it be used for shielding/protection around a wire (tube) but also as a grounding strap or main lead (flat).
I’m happy to test a couple configs of that to see the connection’s resistance and how a braid weld handles current.
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I looked at every picture on the first 4 pages of Ebay hits, and came to the same conclusion, they are all hollow, and wonder if it is a necessity of manufacturing, that it would unravel otherwise.
I have a horrible hydraulic crimper that I tried to use to flatten the braid, and cold weld it between two 0.15mm strips. The cold weld seems highly unlikely, but compression flattening , then spot welding a copper sandwich to that Flattened portion could be a possibility.
I’ll need to experimemt more, and get my air filter positioned to eat the flux smoke.
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Could be. 
But you need the tube for shielding or protecting cable so maybe they just decided to use one type for all many applications? They have to be flattened anyway for storage and shipping.
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