Hand-building a thruster Li-ion pack,
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
Uncle Sihai’s paddleboard thruster Li-ion pack (no voice-over, caption ‘for viewing only, do not imitate’): gather the parts, lay out 18650s in 2P14S and spot weld, connect the sense wires and mark their order, cut a wiring port in the case and a charge / discharge port (XT90), before plugging in the harness check each tap with a multimeter for rising voltage to confirm the order, check the output voltage and charge to wake it if there is none, structural adhesive on the case openings for waterproofing, finished ‘14S 24Ah 120A BMS’
A music-only video, everything in captions: gather the parts; lay out the cells in 2P14S (spot weld the nickel strip); connect the sense wires; cut a wiring port in the case lid; mark the wire order (each sense wire); cut the charge / discharge port and fit an XT90; before plugging in the harness, measure again with a multimeter to confirm the soldered wire order, rising step by step; measure the output voltage, charge to wake it if there is none; smear structural adhesive over the case openings for waterproofing; finished label 14S 24Ah 120A BMS. 102 comments: every pack needs a BMS, right; how much to make one; would a BYD 3.2 cell at ¥20 each work; wouldn’t big CATL prismatic cells be better; the nickel strip can’t carry the current; ‘hand-built with an AWithZ UF20B’.
Outcome
| Goal | 14S Li-ion pack for a paddleboard thruster |
| Build | 18650 2P14S + 14S 120A BMS + XT90, waterproof case |
| Result | Finished, output voltage normal · verified on camera: Multimeter checks each tap and the output at 130–155s |
Steps5 steps · click a frame to jump
1. Gather the parts; lay out the cells in 2P14S, spot weldGather the parts; lay out the cells in 2P14S; spot-weld the nickel strip (4s on camera).
00:00 – 00:23
2. Connect the sense wires; cut the wiring port; mark the wire orderConnect the sense wires; cut a wiring port in the case; mark the wire order.
00:23 – 01:07
3. Multimeter; cut the charge / discharge port, XT90Multimeter (ranges 2V / 20V / 200V / 10A); cut the charge / discharge port; fit the XT90.
01:35 – 01:57
4. Check the wire order before plugging in, rising step by step; check output, charge to wake if noneBefore plugging in the harness, measure again to confirm the soldered wire order; rising step by step; measure the output voltage, charge to wake it if there is none.
02:10 – 02:30
5. Structural adhesive on the openings for waterproofing; finished 14S 24Ah 120ASmear structural adhesive over the case openings for waterproofing; finished label 14S 24Ah 120A BMS.
02:35 – 02:51
Bill of materials
| 18650 cells ×28 | 2P14S |
| Spot welder (U3pro) ×1 | Spot welding |
| 14S 120A BMS + sense wires ×1 | Protection |
| Waterproof case / XT90 / structural adhesive | Enclosure |
| Multimeter ×1 | Check wire order / output |
Creator’s tips
- Mark the sense-wire order, and before plugging in the harness measure again — the voltages should rise step by step 02:10
- No output voltage? Charge first to wake the BMS 02:30
- Structural adhesive over the case openings for waterproofing (used on water) 01:33
Pitfalls
- Comment: nickel strip can’t carry the current (a thruster draws a lot)
Li-ion safety
- Caption: for viewing only, do not imitate 00:00
