Creator TOP speaks to FPV pilots: field battery boxes, long-range packs and radio batteries are all built from cells, and he has already posted a welding tutorial, an internal-resistance test method, wiring diagrams and an open-source battery-box shell. The key piece of kit is a spot welder; this time he upgrades to the AWithZ UF20B and unboxes it while explaining how to use it. First he shows that a soldering iron struggles to tin a cell terminal, gives cold joints, and long heating is a safety risk, while the spot welder fixes it solid with a few small sparks. Nameplate: max output voltage 6V, max current 1750A, power 10.5kW. Feature-wise he likes the switchable trigger mode: in auto the weld fires as soon as the pen tips press down, in manual you can position first and then press the button to fire, which feels more assured; there are plenty of parameters (trigger time, multi-pulse) but he basically only uses the gear. Too high a gear burns through the strip, too low won’t hold; with 0.15mm nickel-plated steel strip folded double as the example: gear 1 is too shallow and pulls apart with one tug, gear 4 won’t pull apart but is shallow, gear 6 welds through to the back, gear 7 is thoroughly perfect — for 0.15, remember gear 7; gear 99 is for thicker material, up to 0.4mm. The settings menu has a page-by-page ‘experience sharing’ tutorial that is beginner-friendly. Closing: battery-shop bosses drive Ferraris, play with quads and never run short of pocket money, link in the showcase.