So I've been looking to make a spot welder for an 18650 battery pack. I found a few videos of people using lead acid car batteries with a solenoid relay to put out quick bursts of energy (such as this: https://www.youtube.com/watch?v=o4NaDMoEHxU). I wanted to follow this but I can't find any cheap car batteries with high current capabilities nearby. So I found these high discharge lithium ion polymer batteries (https://www.ebay.com/itm/4-SPIM08HP...h=item2a9dd7b58d:g:mskAAOSwhfdaakSO:rk:3:pf:0) that can put out 200 A continuous that I would like to use as a high current source. Seems good to me. What do the experts think?