A post by Miduoduo314
Creator’s own settings as stated in the video (timestamps link to the moment). Not official values — test on scrap first.
Bill of materials
Welder, accessories, consumables and parts used in this build; quantities and specs are editable Download BOMDescription
Photo post: hand-built DIY 12V lithium pack — 6 × 21700 (orange) in 3S2P, welder at gear 09 in auto mode, clean welds, with a BMS, measured 11.779V
12-image tutorial: a hand-built DIY lithium pack; the finished piece is an orange 21700 pack + BMS + red / black XT leads; a bench meter reads 11.779V DC (a 12V lithium pack); 6 × 21700 lithium cells; welder at gear 09 (screen shows auto, trigger 0.5s, pulse count 1); the spot welds look really clean. Comments: aren’t the four joined together connected to those two? Two sets of leads, one for charge and one for discharge? (creator didn’t answer); is a BMS a must (creator: yes); is the nickel strip 0.1, still blackening at such a low gear (creator: no); ‘burnt black and you still call the welds clean’; I just bought this welder for ¥600, what did you pay (creator: yes); with a spot welder, no more soldering damaging cells, just flip the nickel over.
Outcome
| Goal | DIY 12V 21700 lithium pack |
| Build | 6 × 21700 in 3S2P + BMS |
| Result | Measured 11.779V · verified on camera: Images 3–4, bench meter reads 11.779V |
Steps5 steps · click a frame to jump
1. Finished: pack + BMS + leadsOrange 21700 pack, BMS, red and black leads.
- 2. 12V lithium pack measures 11.779V
Bench multimeter, 11.779V DC.
3. 6 × 21700 lithium cellsSix orange 21700s.
- 4. Welder at gear 09, auto mode
Screen shows weld mode auto, gear 09, trigger 0.5s, pulse count 1; trigger interface.
- 5. The spot welds look really clean
Nickel strip welded onto the 21700s.
Bill of materials
| 21700 cells ×6 | 3S2P |
| BMS ×1 | Protection |
| AWithZ welder (U3pro) ×1 | Gear 09, auto · Spot welding |
| Bench multimeter ×1 | Voltage measurement |
Measured on camera
| Pack voltage | 11.779 V 00:00 |
Creator’s tips
- Comments / creator: a BMS is a must
Pitfalls
- Comments: welds blackened (creator denies the nickel strip is 0.1)
Li-ion safety
- Lithium batteries aren’t inherently safe; a BMS is a must (comment, creator agrees)
Quotes
Comment insightsanswered 3 · open 3 · corrections 1
Answered by the creator
Open questions
Corrections from viewers
Having a spot welder is still handier. Before, cylindrical cells could only be soldered, now no worry about damaging the cells; before, when a pouch cell's positive aluminum tab broke off you couldn't solder it and had to throw it away, now just weld nickel on however you like
Reply @为羞布牢搬:
Having a spot welder is still handier. Before, cylindrical cells could only be soldered, now no worry about damaging the cells; before, when a pouch cell's positive aluminum tab broke off you couldn't solder it and had to throw it away, now just weld nickel on however you like
Reply @为羞布牢搬:
Having a spot welder is still handier. Before, cylindrical cells could only be soldered, now no worry about damaging the cells; before, when a pouch cell's positive aluminum tab broke off you couldn't solder it and had to throw it away, now just weld nickel on however you like
Reply @为羞布牢搬: