Build a portable solar power bank that charges a single 18650 lithium cell in the sun and outputs a stable 5V USB.
Use a TP4056 with built-in protection (BMS). Panel voltage MUST be 5-6V (NOT 12V). Add a Schottky diode in series with the panel to prevent reverse current at night.
| Component | Qty | Spec | Cost | Source |
|---|---|---|---|---|
| 6V 1W solar panel | 1 | 6V 166mA | $4 | — |
| TP4056 charger module with BMS | 1 | Type-C | $1 | — |
| 18650 lithium cell | 1 | 3000mAh protected | $6 | — |
| MT3608 boost to 5V | 1 | $1.50 | — | |
| Schottky diode 1N5817 | 1 | $0.10 | — |
01
Solder the panel leads
Add the 1N5817 in series on the positive lead.
02
Connect to TP4056 IN+/IN-
Observe polarity. Insert the 18650 in its holder.
03
Wire boost module
TP4056 OUT goes to MT3608 IN. Adjust MT3608 trimpot to exactly 5.05V.