The ¥9.9 mini fan I bought last year stopped charging — repaired with one bigger cell, no more runtime anxiety! The same home battery welder as in the video is in my shop window
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
A ¥9.9 mini fan that won’t charge: inside is a single 14500 Li-ion cell in a holder, easy to swap; a bigger cell goes in (too fat, so a hole is cut in the shell and part of it sticks out), AWithZ welder in auto mode at gear 50; runtime is now “badass”
The ¥9.9 mini fan bought last year won’t charge. Opened up: a single lithium cell, decent build, with a cell holder so it can be swapped straight out, but no matching cell on hand; cramming in a bigger cell would end the runtime anxiety. The old cell is pried off and the new one welded with an AWithZ welder (screen: auto mode, gear 50, trigger 0.5s, 1 pulse, 30°C); on trial fit the cell is too fat to go in, so the only option is a hole in the shell with part of it sticking out; runtime is now badass — the catch is that part of it sticks out (self-mocking). Comments: it’s just a 14500, buy one (creator: is it worth repairing a kid’s broken toy like this?); suggest heat-shrink over it; why not swap in an outrunner (no thanks).
Outcome
| Goal | Bigger cell for a ¥9.9 mini fan |
| Build | Single 14500 → bigger Li-ion cell (sticking out) |
| Result | Much longer runtime but the cell is exposed · verified on camera: 84–98s test run and explanation |
Steps3 steps · click a frame to jump
1. Opened up: single Li-ion cell in a holderThe ¥9.9 mini fan won’t charge; opened up, a single lithium cell, decent build, with a holder so it swaps straight out, but no such cell on hand; put in a bigger cell and the runtime anxiety is gone.
00:00 – 00:25
2. Pry off the old cell, weld the new one with the AWithZ in auto at gear 50With it apart, pry off the old cell; the welder screen shows auto, gear 50, trigger 0.5s, 1 pulse; weld the new cell.
00:29 – 01:06
3. Cell too fat, hole in the shell, part exposed; badass runtimeTrial fit — the cell is too fat to go in, the only option is a hole with part sticking out; runtime is badass, the catch is that part of it sticks out.
01:24 – 01:38
Bill of materials
| ¥9.9 mini fan ×1 | Single 14500 · Item under repair |
| Bigger Li-ion cell ×1 | Replacement |
| AWithZ welder (U3pro) ×1 | Auto, gear 50 · Spot welding |
Creator’s tips
- Check the holder size before picking a cell; too fat and you have to cut the shell 01:24
- Comment: put heat-shrink over the exposed cell
Pitfalls
- The cell was too fat to fit; hole cut in the shell, part exposed 01:24
Li-ion safety
- An exposed cell has no protection; heat-shrink recommended (comment)
Quotes
Cost & time
| Small fan | ¥9.9 |
