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I guess I need to make 72v 35ah battery pack

Finally the turtle boat from china arrived. I think I'm ready to get started now. My plan is to use this 0.20 copper with 0.15 nickel. I have no idea what to set the KWelder at. I'll have to practice a while before getting started.
20240618_181823.jpg
 
I started practicing my welding. So far I don't feel like it's going so well. This is 0.2 mm copper, and 0.15 nickel. Seems like it can barely work even set on 500j. It's kind of inconsistent too. It might make a good weld, but the next one barely holds. Suggestions are welcome. I just ordered some 0.1 mm nickel to see if thinner nickel will work better. weld test.jpg
 
Obviously I'm going to need to make some changes to my plan. Plan 2 is to try 0.1 nickel instead of 0.15, with my 0.2 copper. I don't have a lot of confidence in it though. Plan 3 will involve gluing the cells together without the plastic holders and hand cutting copper busses from 0.1 mm copper sheet.
 
Theodore Voltaire said:
Obviously I'm going to need to make some changes to my plan. Plan 2 is to try 0.1 nickel instead of 0.15, with my 0.2 copper. I don't have a lot of confidence in it though. Plan 3 will involve gluing the cells together without the plastic holders and hand cutting copper busses from 0.1 mm copper sheet.
Click to expand...
Plan 3 is something I did many times, it works very well with kweld. in alternative recently I have been using the connections in the photo bellow, they are 0.3mm cooper and have a weld area made of 0.15mm nickel.

S54d3332a54c942a99d367bce3ce97533R.jpgS72aa40548c1a4a6e9f20ebe763bde2a4V.jpgS7b99ba4328884faebb7899c43b0640eeB.jpg
 
I figured out a way to salvage the plastic cell holders. It's very easy to snap the little tabs off the holder which allows the cell holder to slide down on the cell. This gives me a flat surface to weld on, but keeps the cells spaced apart.Modified cell holder.jpg
 
Portugaline said:
Plan 3 is something I did many times, it works very well with kweld. in alternative recently I have been using the connections in the photo bellow, they are 0.3mm cooper and have a weld area made of 0.15mm nickel.

View attachment 355350View attachment 355351View attachment 355352
Click to expand...
I was searching those copper/nickel busses yesterday. I wasn't able to tell from the pictures if they were copper on the bottom or not. Sounds like you're saying they're nickel. What would work best is if I could find those kind of busses with spacing to fit my plastic holders. I'm trying my best not to have to glue the cells together, but that's on the table.
 
Theodore Voltaire said:
Obviously I'm going to need to make some changes to my plan. Plan 2 is to try 0.1 nickel instead of 0.15, with my 0.2 copper. I don't have a lot of confidence in it though. Plan 3 will involve gluing the cells together without the plastic holders and hand cutting copper busses from 0.1 mm copper sheet.
Click to expand...
Are you using a good power supply that can deliver adequate current for the kWeld? I ask because on my first spot welding venture I was using a LiPo pack that didn't have quite enough punch; I added another pack in parallel and it produced much more consistent welds (I forget how thick the materials were; but it was also a coper/nickle sandwich.).
 
pwd said:
Are you using a good power supply that can deliver adequate current for the kWeld? I ask because on my first spot welding venture I was using a LiPo pack that didn't have quite enough punch; I added another pack in parallel and it produced much more consistent welds (I forget how thick the materials were; but it was also a coper/nickle sandwich.).
Click to expand...
Having zero experience I can't say if that's a problem or not. I'm using a brand new truck battery that has 900 CCA. I'm thinking if I need a power supply stronger than that I'm doing something wrong?
 
I think I found copper/nickel composite busses for 21700 cells that have the right spacing for my holders. When the turtle boat finally gets here I should have at least couple of options to try.copper strip.JPG
 
Thanks for the updates on your progress Theodore. I’m now looking at building an interim 24s 8AH headway LifePo4 pack; mainly because I have the high amp cells and a massive 8 amp 87.6v charger. Mine is a 2011 and still has the v2CA so I will probably upgrade to a v3 on the bars, leaving the v2 in the frame top for now.
 
DCMotorworks said:
Thanks for the updates on your progress Theodore. I’m now looking at building an interim 24s 8AH headway LifePo4 pack; mainly because I have the high amp cells and a massive 8 amp 87.6v charger. Mine is a 2011 and still has the v2CA so I will probably upgrade to a v3 on the bars, leaving the v2 in the frame top for now.
Click to expand...
Thank you for the encouragement.
 
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