[jonnybear]

Having need to spot weld some batteries, I could not find anyone that could help, not wanting to purchase one on line for around £150 it would not viable for just a few batteries. I started off constructing one using a car battery and a starter relay, found this a bit Heath Robinson as some times the relay would stick and vaporise the nickel tag not good when using on lithium cells. So I decided to build one using a microwave transformer, after much experimentation I came up with a unit which spot welds perfectly, I started off stripping out an old PC power supply case, and removing the ht secondary winding on the transformer ( worst part) I finished up with this, did not cost much a little time and sweat, cost under £20 in parts.
John