An RC-model creator unboxes the more professional P30-series capacitor spot welder he chose for building 21700 power packs. Packaging: an intro card (32 patents worldwide), two accessory boxes and the main unit. Accessories: a 9V15A charger (charges the capacitors), a foot switch, an 18650 plastic welding jig, two spare pairs of welding pins, a very thick, soft pure-copper pen cable (later checked: 25 mm²), nickel strip (0.1 or 0.15), a file for dressing the tips, and the manual (battery icons, system settings, thermal protection — no charging above 60℃ or below -10℃, 2.4-inch color screen, about 180×131×80mm, auto power-off after 8 minutes idle, three ‘welding experience’ notes). The body is a boxy plastic shell but feels heavy; P30C model mark at bottom right; on the front a 2.4-inch color screen, power and control keys, two welding-pen ports and a trigger port; XT60 input at the rear. Nameplate: welding output voltage 9V (MAX), output current 2430A (MAX), max output power 21.8kW, input 9V/15A. Red warning: the two tips of a P-series pen may only touch the same terminal plate of a cell — never touch the two plates separately, or it shorts and catches fire. Main screen on power-up: welding mode (manual / auto), preheat time, interval time, welding gear, trigger time, repeat count; OK means ready to weld, a slash means low battery; internal temperature shows 27℃; system settings: language, repeat interval, welding sound, screen brightness, screen rotation, auto power-off, factory reset; plus three ‘welding experience’ notes (results depend on pen pressure, material thickness and stacking order) — helpful for beginners. Inside are three 1000F supercapacitors; from completely flat, 5 minutes of charging is enough to weld. The pins are imported alumina copper. Test: straight to 0.2×10mm copper strip stacked on 0.15 nickel-plated steel strip (the nickel layer adds resistance so the copper can be welded to the cell), starting at gear 600 (max 999) with an external welding-current meter connected; he recommends keeping the charger plugged in while welding to top up at any time. Gear 600: four welds, peak 2070A, RMS 1574A; pulling tears the strip apart, fully welded. Down to gear 500: 2052A, both welds hold too (one torn through, one shows copper flow), but to be safe 550–600; back to 600 for 3 more shots, 6 welds, all tear apart with no weld letting go, current 2107A — the rated max is 2400-odd amps and gear 600 is already enough. Conclusion: 0.1/0.15/0.2 and even 0.3 nickel-plated steel strip, and 0.2 copper stacked on 0.1/0.15 nickel, are no problem at all — fully up to building 21700 power packs; long-term performance to be seen once he builds packs with it. Comments: ‘only 2000A at this price’, doubts that 2000A can weld 0.2 copper on 0.15, someone’s ¥336 home-built welder does the same but with tearing, and someone says 0.15+0.15 tears at gear 270 after switching to a one-piece pen.