The Very First 20p Pack

I’ve just soldered my very first pack of 20 parallel 18650 cells. It doesn’t look beautiful, but it seems to work fine.

20 cells in parallel

  • cells are connected using 0.2 mm copper wire (~€0.10 per 1 m)
  • busbars are made of 1 mm thick copper sheet, they are 10 mm wide (~€0.20 per bus bar)
  • the pack uses two 4×5 plastic cell spacers bought on AliExpress (~€0.5 per spacer)
  • the module consists of 20 cells between 700 - 1500 mAh each (it’s made of lower quality cells), I expect it to have around 20 Ah in total

A few thoughts so far:

  • cutting busbars from a 1 mm copper sheet is easier than I initially thought - the cheapest cutters do the job well
  • I need a little bit more powerful soldering iron to solder cells and busbars - especially the bottom side of a cell is a challenge
  • I’ll try to make my cell spacers on my own (e.g. wooden ones)


I'm Kuba Kuźma — Ruby on Rails and JavaScript Developer

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