Straight short, ‘blew it up, bro’, cotton swab from the bag to wipe his hand — just got cut by the nickel strip again, the welding pen touched the strip and blew twice; the corner of the strip went in and it ‘burst like tomato juice’, this build really wrecks your hands. The 50A copper lug connected and a dab of solder on it; meant to spot-weld it onto the copper plate but found the lug too thick, so back to the old way, screw it, heat-shrink over it, onto the copper plate, then spot-weld to the main positive and negative; when soldering the leads the positive must go to the red positive, get it wrong and it blows up again. Nearly blew it up again just now: welding the main negative, this pen isn’t fully wrapped, it has a gap, the gap touched a positive, bang, the cable was ripped straight off, terrifying, the cable feels unsafely designed — not fully enclosed, and yes enclosing it hurts cooling, but I keep touching other things, clip another strip and it blows; same recipe as before: high-temperature glue, then cutting paper, then a layer of fireproof board on top, this corner is the blackened spot; the short blew right at the pen; this time the main +/− get sealed with 704 silicone first, then a few turns of fiber tape and the sense harness can be soldered. Comments (116): sleeve the pen in nylon braided mesh (noted); my pen is identical and it blew straight through the 50 mm² welding cable, only a few strands left (that bad?); wrap it in polyimide film; no BMS? not on LiFePO4?; solder the main +/− straight onto the copper plate (I prefer screws); safety first (scared stiff); running deliveries in Changsha.