Sharing money-saving experience from hand-building lithium packs so beginners spend as little as possible. The three-piece kit: the welder is essential, the internal-resistance meter is optional, the load tester is optional — a beginner only needs a welder, skip the other two for now; early on, only build small packs and order straight from the cell brand’s official channels (EVE official site / Tmall / Alibaba; the page shows 18650 3.6V 3200mAh / 2850mAh etc.), which basically needs no testing — with a welder you can build right away; think about instruments later when going to big capacity. Key point — which welder suits a beginner: buy the most expensive one you can accept within your budget, and go for a big brand as far as possible; this is the third welder I’ve bought (AWithZ); one feature is very beginner-friendly: the pen sits on the cell for ages and nothing happens, because the manual weld button hasn’t been pressed — press it and it welds instantly, the semi-auto mode; beginners often mis-place the spot or set the nickel tab crooked, and if the pen welds the moment it touches, the cell is ruined, so a semi-auto button is best to have; there is also a repeat-pulse mode that welds the same spot repeatedly, suited to copper sheet that needs more power — hold the pen steady and it fires up to 3 welds in quick succession. Mine is the AWithZ U3 Pro: pure nickel 0.2mm MAX, and it also does steel and copper sheet (copper 0.1 MAX; nickel-plated / steel / iron 0.35 MAX); nameplate U3 battery spot welder, 4.2V MAX, Type-C 5V/2.1A, USB 5V/2.4A, 11000mAh 40.7Wh, Juequi Technology; plenty for a beginner. Consumables: glass-fiber tape, heat-shrink film, fish paper. A special note on cells: this is the positive, this side is negative — many people don’t know the whole can is negative; open one up and everything except the positive is negative, so positive insulation is critical, always use positive fish paper. Non-essential accessories aren’t covered; get the three-piece kit straight and you save a lot. Comments: asking for the EVE official link (search results are all ads) (2); lend me the welder for two spots nearby; can UV glue join them; what battery for a 24-set net-hauling boat; a mis-weld ruins the cell? can’t you pull it off and re-weld?