Battery calibration (UPS HAT)

Hardware

SeedSigner works out of the box with the Waveshare UPS HAT (C). The stock 1000mAh battery provides about 4 hours of runtime.

The battery meter will also work with any hardware that uses an INA219 battery meter connected over I2C at address 0x43.

Battery curves and calibration

Calibration runs the discharge test from Tools → Battery Calibration, logging a voltage sample every minute while the device discharges. That log is converted into a voltage-to-percent curve in 5% steps and written to the microSD card as custom_battery_discharge_curve.json (in the MicroSD directory).

By default, the battery meter assumes a standard 3.7V LiPo cell.

On boot, SeedSigner loads the custom curve when it exists; otherwise it falls back to the built-in default curve.