DIY 21700 Power Bank Case with USB-C Cable

Build a compact power bank around one correctly matched 21700 cell. This solder-free case combines charging electronics, a detachable USB-C cable arrangement and battery-level indicators.

✅ Assemble without soldering - The cell holder uses a drop-in contact arrangement.

✅ Keep a charging cable with the case - The integrated detachable cable reduces another loose accessory.

✅ Check remaining charge - Four indicators show the battery level.

✅ Access the cell for maintenance - The shell can be opened for a correctly performed replacement.

Choose the Cell Before Completing the Build

The case is designed for one suitable flat-top 21700 cell, supplied separately. Confirm cell dimensions, chemistry and current capability, then install with the specified polarity; the spring marks the negative contact.

The electronics support up to the stated PD 20 W mode with compatible equipment. Actual output depends on the cell, cable and connected device. This purchase is the case, not a ready-charged battery pack.

Technical details

• DIY single-21700 power-bank housing
• Flat-top cell required, not included
• Solder-free assembly
• USB output and bidirectional USB-C
• Detachable USB-C cable arrangement
• Battery-level indicators
• Black or grey

Choose a matched cell and complete your compact power-bank project.