Every spot welding machine I have worked with had a electrode pressure detection of kind before power is allowed, it can also be dangerous if used without and no eye protection.
Max.

Im using a foot switch. The foot switch then activates the timer (milliseconds pulse ) which then gives the signal to the mosfets.

I had been using a heavy duty 300a continuous solenoid but after maybe just 50 welds the contacts burned up im assuming since it would pass voltage by no amps... I need to make at least 8 welds per each cell(4 on positive & negative) x 450+ cells... Some people have great luck using the solenoid method but.... Ill include a picture of my new mosfet welder later tonight after I finish attaching welding leads etc... Below is a picture of what most diy lithium battery / powerwall hobbyist's are using for spot welding...

@MisterBill2

great. Thx u again

 

Hey @bigjoncoop,

I'm interested in building a battery spot welder like yours. Did you ever get to complete your project? Any pictures to share? Thanks.

Regards,
brizz