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    TaK's Battery Build - 18650 w DIY CD Welder- Lessons Learned

    OK. The welder. There were some questions on the details of my welder. Here is the schematic: You can make it really easily if you have a programmable bench power supply. If you do not, you can make it very cheaply with a charge pump doubler. I'll explain in detail later. There is...
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    TaK's Battery Build - 18650 w DIY CD Welder- Lessons Learned

    It's a bench power supply. I'll make a post shortly on the welder itself since several people have asked. The voltage rating of the cap just has to be high enough for whatever voltage you're charging it to. The voltage depends on the amount of energy you want to store as well as the capacity...
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    TaK's Battery Build - 18650 w DIY CD Welder- Lessons Learned

    Battery update first. Answer questions second. Update: I attached the BMS wires to the tabs on the metal strips that parallel each bank of cells. Then I folded them over and Kapton taped them down. I taped the under the tabs first for some structure and insulation then I taped over the tabs...
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    TaK's Battery Build - 18650 w DIY CD Welder- Lessons Learned

    okashira- Thank you for sharing that document. I read through it and I can see a lot of time spent. It's nice to see a community with genuinely helpful members. That said, I think it would be very challenging to adjust this methodology to a capacitive discharge type of welder. The problem...
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    TaK's Battery Build - 18650 w DIY CD Welder- Lessons Learned

    I agree, and another thing is the consistency of the welds. In my testing, when I was not using a V, differences could be seen from weld to weld which I believe were from how hard I was pressing and how far apart the probe tips were from one another. The V gap helps make your welds invariant...
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    TaK's Battery Build - 18650 w DIY CD Welder- Lessons Learned

    Progress update: I've welded the parallel nickel strips to the pack: Since there will be almost zero current going through this strip, I cut the 3/8" nickel strip in half to make it a little easier to work with. I'll solder wires onto the overhanging tabs to go to the BMS and then fold the...
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    TaK's Battery Build - 18650 w DIY CD Welder- Lessons Learned

    Thanks. Correct, there's no pulse control included here. This is definitely a KISS build. My understanding is that if you want to make a larger weld that needs a lot more energy, then the pulse control becomes critical. Also, I'm sure it would help keep my probe tips in better shape. On the...
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    TaK's Battery Build - 18650 w DIY CD Welder- Lessons Learned

    How about now?
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    TaK's Battery Build - 18650 w DIY CD Welder- Lessons Learned

    Hello, This is my first contribution to this forum. I've been working on my second ebike battery pack. This one is made with 18650 cells in a 14S4P configuration. I decided to make a capacitive discharge welder to properly assemble the pack since I already had most of the necessary...
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