Recycle battery from laptop cells.Simple 3S4P pack.

Soldering around on 18650 Li-Ion batteries? I was always suspicious of that. If you don't know exactly what you're doing here, your house will burn down some weeks/month later, e.g. because of wrong solder or fuse wire too strong or tiny holes in the metal after tearing off the contact plates and air got into the cell. So I found a more elegant solution. See the channel jehugarcia , mexico.
(E*ay item 233849980002 , "7S Power Wall Balancer PCB 18650 Battery Holder Case 20/40/60A Protection Board" )
One holder holds 14 cells, giving about 100 Wh. If I have collected and tested enough other used cells, then I simply screw another holder(s) onto the existing battery bank. (My only "problem" was finding the right connector FC 16P 2x8 Pin Header for the balancer cable IDC 16 2,54mm. Instead of special pressing pliers, I simply use a small vice.)
Greetings from germany

cool but now i d like to know about the bms conections