USB power bank
18650 charger plus protection plus a 5 V boost output. A TP4056 board charges the cell from USB and protects it; an MT3608 boost module lifts the 3–4.2 V cell to 5.1 V for a phone. Set the MT3608’s trimmer before connecting anything: it ships set to about 12 V.
Build it in the labGuided build, test sheet and fault finding, free in your browser.
Parts list
- Bench power supply
- TP4056 charger module
- 18650 Li-ion cell
- MT3608 boost module
- Resistor
Test procedure
Each test has an expected value and a pass range, like a factory test sheet:
- USB output at 0.5 A (on battery)
- Charge current with USB in, phone unplugged
- Boost efficiency at 0.5 A
How it works
What it does: 18650 charger plus protection plus a 5 V boost output.
Build it (guided or ready-made), then run its test procedure below. Every test has an expected value and a pass range, just like a factory test sheet.
Background
Every power bank in a shop is these three blocks in a plastic case.