18650 battery packs are dangerous so you might want to ask someone here that has more experience in building batteries. I don’t want to burn your house down. Sorry. No.
I have a cheap spot welder that you can borrow if you need it
I have a question about hooking up a new battery pack to a sightly used other battery where talking more or less 25 cycles. I know it’s bad to hook them up where the it’s like more than 100.
Is it fine 