LV5
Lefeng answers ‘support says the UF20B can weld copper directly (with flux)’: two Jiashikai cells in parallel make a 30000mAh LiFePO4 power bank (new board ¥20-odd), 0.1 copper + 0.1/0.12 nickel-plated straight on — gear 70 spots look pretty but drop off with a tug, gear 90 four spots still not solid; switch to a 0.15 nickel-plated base, gear 30 already solid, 40 tears, 60 can’t be pulled, ‘don’t recommend copper straight on with this model’; B1/B− to the board, sealed with epoxy board + glue, like a single big cell super-fast-charging power bank
A follower asked whether the UF20B can weld copper stacked directly, I said no, he said support says it can with flux, so here’s the video, see for yourself. The four Jiashikai cells torn down last time (the leaky group out of the 15S is discarded), BMS and charge module not removed, bought a new LiFePO4 board with more ports; two Jiashikai in parallel for a power bank, 30,000 mAh; into the holder in parallel, 3.2V output, spot weld + to + and − to −; many previous copper-and-nickel weld marks on top; switch on the UF20B, charges quickly, try to charge it full before welding; copper 0.1, nickel 0.12 (maybe 0.1, no more than 0.12); added a braided sleeve to the lead himself, No. 6 lead; preheat 10, (interval) 20; straight on first: 0.1 copper + 0.1/0.12 nickel-plated, gear 40 → 70 (dangerous, don’t imitate, same unit as in the showcase): spots are OK but a tug shows they’re not solid, ‘so I don’t recommend copper straight on’; up to gear 90 with four spots, pretty spots but still not solid, don’t recommend stacking copper directly on this model. Next, nickel base: 0.15 nickel-plated steel strip as the base, with experience gear 30 is already very solid (a bit dark, current is high); 0.15 strip at gear 40 tears; up to gear 60 blows two holes; then 0.1 copper on the base: can’t be pulled, can’t be pulled off, clearly far more solid than straight onto the cell; with this model a nickel base works, straight on is not recommended, a thinner strip might stack. After welding, main + / − soldered to B+/B−, an epoxy board sealed on top and glue poured everywhere else; the power bank works, 93% charge; case closed, OK; the two Jiashikai cells sit inside like a single big cell, fast charge, charge board ¥20-odd, wrap with tape; 30,000 mAh, more than enough for food delivery. 68 comments: cells can’t be torn down over and over, three times and they’re basically done; music too loud; will a single layer of 0.3 nickel do; 0.15 copper under, 0.2 nickel-plated on top, weld directly?; can this machine do a 0.2 nickel base; pure nickel costs more than copper strip and doesn’t spark; only this episode showed me copper straight on isn’t stable; 32140 1P16S without a BMS?
A follower asked whether the AWithZ UF20B can weld copper stacked directly; I said probably not, he said support says it can with flux. Fine — if you don’t believe me, don’t ask me again, the video is right here, see for yourself. The welder is the AWithZ UF20B from my showcase, upgraded No. 6 welding pen: copper straight on vs copper on a nickel base. Also found some followers haven’t even figured out nickel base layers… mainly I turned the power bank into a 30000mAh one, and it’s a joyProjectsCrazyFun