Schematic: PDF file in repository
The battery port voltage can be 12V or 24V.
The MPPT port is connected to the battery via the DC/DC converter. This port is typically used as the solar panel input.
If building a hybrid system, the MPPT port can be used for wind generator input (after rectification) and the solar panel is connected to the PWM port. For a pure wind energy system, the PWM port can be used for controlling a dump load.
The load output protects the battery from deep-discharge if there is not sufficient power from solar panel or wind turbine. It is switched on the high-side to prevent issues with second GND paths e.g. via USB or audio cables.
- MPPT terminal
- Max. 80V (using 100V MOSFETs)
- DC/DC converter inductor current max. 20A, resulting in approx. 560 W maximum power for 24V systems
- Battery terminal
- 10 V - 32 V (supporting 12 V and 24 V battery systems)
- Max. current: 20A
- High-side load output switch
- Max. current: 20A
- PWM input/output terminal
- Max. current: 20A
- Fast inductor current measurement (sample rate > 300 kHz) to allow implementation of digital DC/DC control algorithms
- New STM32G431 ARM MCU with advanced digital power conversion features
- Expandable via Olimex Universal Extension Connector (UEXT)
- Peripheral power connector for power-hungry extensions like GSM boards
- Only single LED as power indicator. Additional user interface (LED gauges, displays, etc.) will be included in separate PCB in front panel housing and connected via UEXT
- Optional EXT PCB on socket in bottom right corner
- Dual USB charging port
- CAN interface
- Serial interface
- Optional USB Micro B connector for firmware upgrades and settings via virtual COM port.
- Optional ESP32 module for WiFi / Bluetooth
- Optional external temperature sensor (10k NTC)
- MOSFETs need to be attached to an external heat sink (preliminary solution with thick aluminum sheet metal, final solution with aluminum extrusion profile)
- Panel for screw terminals and communications ports might be made from plate material to allow easy adjustment to different features.
First draft sketch of a housing with LED UI module:
