[Full reveal] Hand-building a ‘TNT’ C4-style power bank! Do not take it outside

A ‘TNT’ C4-style power bank from a dead power bank’s charge/discharge board + 18650s + a kraft-paper tube, plus an unboxing of the AWithZ portable welder (setting around 4.3, mid-range)

The creator (a designer-toy channel) wanted a C4 explosive-pack power bank with a timer look. Materials: a dead power bank (for its charge/discharge board), 18650 cells, a few circuit boards as decoration, a glue gun, wire, kraft paper. Along the way he unboxes the AWithZ portable welder: about the size of a 10000mAh power bank, doubles as a power bank itself, comes with a welding pen (very thick copper tip), nickel strip, manual, charging cable and sandpaper; in settings he switches to Chinese, turns on the welding sound, sets auto trigger 0.5s / 1.0s; power at eight-point-something throws too many sparks and punches through the cell, too little won’t hold, so mid-range around 4.3 is right. Kraft paper is misted with a little water to soften it, then rolled into cell tubes; several groups of cells go in parallel (red is positive — remember parallel, not series), get stuffed into the paper tube and fixed with hot glue, the charge/discharge panel and decorative boards are glued on, and the wires are spot-welded instead of soldered (no preheat, welds wherever you touch, with vibration feedback); powered up it shows 34% charge; a coiled cable and black tape finish the weathered look. Warning: don’t take it into crowds or onto public transport.

Outcome

Steps8 steps · click a frame to jump

1. 
   1. Concept and materials

   A power bank styled with a timer; materials: a dead power bank (for its charge/discharge board), 18650s, a few circuit boards for decoration, a glue gun, some wire, a pack of kraft paper.

   00:00 – 00:40
2. 
   2. Unboxing the AWithZ portable welder

   Used to poke around with solder; now a spot welder; portable saves space, easy to carry, also useful for model power packs; same size as a 10000mAh power bank and works as a power bank itself; welding pen, nickel strip, manual, charging cable, sandpaper.

   00:40 – 01:34
3. 
   3. Plug in the pen and test

   Simple to use with lots of functions; the welding pen’s copper tip is very thick, so push hard when plugging it in; hook up the leads and do a quick test.

   01:34 – 01:48
4. 
   4. Mist the kraft paper and roll cell tubes

   Little trick: when rolling thick paper, mist it with a little water to soften and shape it so it fits tighter — don’t overdo it; smooth it out, put the cells in and roll; do the other groups the same way.

   01:48 – 02:10
5. 
   5. Set the parameters: around 4.3, Chinese menu, auto trigger

   Too much power punches through the cell, too little won’t hold; big sparks mean it’s too high; switch to Chinese, turn on the welding sound; auto trigger 0.5s / 1.0s; eight-point-something is too much, so set mid-range around 4.3, then test that it grips.

   02:10 – 02:42
6. 
   6. Weld in parallel, hot-glue into the tube, attach the panel

   Strip the wires; weld all the cells up according to the wiring groups, red is positive, and remember it’s parallel, not series; stuff into the paper tube, fix with hot glue, glue on the charge/discharge panel with plenty of glue and press it down.

   02:42 – 03:09
7. 
   7. Spot-weld the wires instead of soldering; powered up, 34%

   Flatten the paper tube and tidy the wires, then weld the wires with the spot welder: fast, no preheat, welds wherever you touch, with vibration feedback in your hand; power up the circuit and it reads 34%.

   03:09 – 03:40
8. 
   8. Weathering and safety warning

   Plug a coiled cable into each side, black electrical tape; test charge/discharge and then shoot the glamour shots; advice — don’t take it into crowds or on public transport, or you’ll be misunderstood.

   03:40 – 04:14

Bill of materials

Measured on camera

Creator’s tips

• Mist thick paper with a little water before rolling; it softens, holds its shape and fits tighter 01:52
• Big sparks mean the power is too high; too high punches through the cell, too low won’t hold — set mid-range around 4.3 and test the grip 02:10
• Spot-welding wires beats a soldering iron: no preheat, welds wherever you touch, with vibration feedback 03:22

Pitfalls

• Remember parallel, not series; red is positive 02:52
• The welding pen plug is very thick; push hard when inserting 01:38

Li-ion safety

• It looks like an explosive pack: don’t take it into crowds or on public transport 04:02
• Too much power punches through the cell 02:10

Quotes