Alternate Power Inputs
Edit on GitHubUSB power banks, solar, bench supplies and battery swaps in the field
Alternate Power Inputs
Overview
The beacon normally runs on a single 18650, but the TP4056’s USB-C input accepts any 5 V source. This page covers the practical alternatives and their caveats.
USB Power Bank
| Use | Setup |
|---|---|
| Bench work | Connect a power bank to the TP4056 USB-C |
| Field top-up | Recharge the cell through the same port |
| Continuous operation | Possible, but the bank’s auto-off may cut power |
Solar Panel
| Panel | Notes |
|---|---|
| 5 V USB solar panel | Works, slow; panel output varies with sun |
| 6 V panels | May exceed the TP4056 input rating |
Warning
Keep panel output near 5 V. The TP4056 input is rated around 5-6 V; overvoltage can damage the charger.
Bench Supply
For development, a bench supply set to 5 V with current limiting (start at 500 mA) into the TP4056 USB input is ideal. Never feed the ESP32 5 V rail directly without the TP4056 in the path unless you understand the circuit.
Field Battery Swap
- Power off the beacon.
- Swap the 18650 (mode is preserved in RTC RAM).
- Power on. The beacon resumes the saved mode.
The RTC RAM keeps the mode and counters across the swap; only a full power loss longer than the RTC retention clears them.