Quote

Ben, was the lack of weld penetration due to a low battery voltage, low current output, or a problem with the programming etc.?

Hi Alan - those comments were based on the 2nd time I built this. That build did 7 or 8 weak welds then the probes became 'live' without pressing the foot switch - did one very strong pulse that pretty much destroyed the nickel strip - some smoke came from the pcb then the Arduino went off and never came back on...I'm afraid I don't have the skills to troubleshoot this when it goes wrong and there doesn't seem to be a lot of help out there, for this build, for someone of my level of expertiseFor this 3rd build I used thicker probe wires (4 gauge) and 5mm diameter solid copper probes but it's just as likely the previous failures were down to dodgy soldering or some other error in the build process.I'm using a 45aH car battery for the juice which was recommended by the author of the instructable.I'm going to test this build for at least 50-100 welds before I shell out for the new cells as I'm not sure I can go through the process of building it again and there doesn't seem to be any Chinese options available that will run off a UK domestic mains supply.What's everyone else using to build packs in the UK?...Is there a welder out there that I haven't come across?