Daedawatt Ultra MPPT
Custom solar charge controller for maximum power extraction
A custom Maximum Power Point Tracking (MPPT) solar charge controller designed and built in-house. Daedawatt manages the flow of power from solar panels to the battery, monitors efficiency in real time, logs telemetry data, and communicates with the rest of the vehicle over DroneCAN.
- MCU
- ESP32-C3
- Charger IC
- BQ25756
- Protocol
- DroneCAN
- Interface
- WiFi Dashboard
At the core of Daedawatt is the Texas Instruments BQ25756 battery charger IC, which handles enabling and disabling charging, toggling MPPT tracking, setting input current limits, and triggering panel sweeps. An INA226 power monitor provides independent secondary telemetry — by comparing the charger output to the INA226 readings, the system calculates exact load current and real-time MPPT efficiency.
The firmware runs on an ESP32-C3 microcontroller (Adafruit QT Py ESP32-C3), built using the Arduino framework via PlatformIO. It broadcasts telemetry over DroneCAN and exposes a WiFi access point with a live web dashboard at daedawatt.local, updating at 5 Hz with voltage, current, efficiency, and charge status.
Settings like current limits, MPPT algorithms, and logging frequency are configurable over both the web interface and the CAN bus, and are stored persistently in flash memory. An optional SD card enables high-frequency binary telemetry logging, with on-the-fly CSV conversion available through the web interface. OTA firmware updates can be uploaded directly through the browser.