Did you ever see a thin metal tab bonded to a battery terminal with little pock marks? That’s the work of a spot welder. Spot welding is one of those processes that doesn’t offer much in the ...

[Aaron Christophel] has a battery spot welder that costs a not unreasonable 30 euros and can also be used as a novelty power bank. He subjects it to a test and teardown in the video below the break.