System Overview:
Block Diagram
Component Interaction
The controller board forms the central hub of the openSCUPS system. It manages the interaction between all connected components to ensure continuous power delivery and reliable UPS behavior. The board features seven primary connections:
- 1 Power Supply Input
This input is used to provide power to the inverter when the system is operating in power supply mode. - 2 Battery Charger Input
This input is active during charging mode, when the main battery is being recharged. - 3 Mains Voltage Input
This input is used to detect the presence of mains power. When a loss of mains voltage is detected, the system transitions into UPS mode. - 4 ESP8266 Microcontroller antenna
The system is controlled by an ESP8266 microcontroller mounted on a Wemos D1 Mini Pro board, equipped with an external antenna connector for improved wireless communication. - 5 Main Battery I/O
This port connects to the main battery for both charging and discharging. It is a bidirectional connection. - 6 Pulse Battery I/O
This port connects to a secondary, smaller “pulse battery”. This battery is designed to absorb short, high-current demands during the rapid switching that occurs when entering UPS mode. - 7 Output to Inverter
This output supplies continuous power to the inverter. The controller board dynamically switches between power sources (from ports 1, 2, 5, and 6) to ensure that this output remains active at all times, regardless of whether the system is charging, discharging, or switching power modes.
In summary, the controller board handles the dynamic routing of power between inputs and outputs, ensuring a stable power supply to the inverter under all operational conditions. This coordinated switching is key to maintaining uninterrupted operation during transitions between power supply, battery charge, and UPS modes.
Required Components:
Off-the-shelf Components
- LiFePo4 battery: 12,8V 100Ah 1280Wh
- AGM battery: 12V 1,2Ah Q-Batteries 12LS-1.2
- Battery charger: Victron blue smart BSC IP22 HQ2308Y
- Powersupply: 12V 37,5A MW HRP-450-12
- Inverter AC to DC: 12V 220V 450W NTS-450-212EU
- Main switch batterys: 12 pole (Internal 6x switches 32A)
- Main switch 220V: 4 pole (Internal 2x switches 16A)
- Switch cabinet with mounting plate: 60x60x25cm Schneider S3D NSYS3D6625P
Custom Electronics (ESP8266 based control board)
The Wemos D1 Mini Pro is a compact development board based on the ESP8266 Wi-Fi microcontroller. It offers wireless performance and additional flash storage compared to the standard D1 Mini. In the SCUPS controller board, the D1 Mini Pro is used as the main controller, responsible for system logic and communication.
To integrate it into the controller board, the D1 Mini Pro must be equipped with male header pins, allowing it to be inserted into matching female socket headers on the board. This modular design enables easy installation, replacement, and prototyping.
PCB (Printed Circuit Board):
PCB Design Files and Schematics
The PCB was developed using KiCad 7.0, an open-source PCB design tool. All design files, including schematics and board layouts, are publicly available in the project’s GitHub repository:
🔗 SCUPS2 PCB files (KiCad 7.0)
These files can be used to review, modify, or manufacture the controller board.The PCB is designed using
Understanding the Schematics
The complete schematic. The original schematic is made in the Dutch language. Some instructions still have the original name such as “voeding” which stands for “power supply”. Where necessary, the translation will be indicated
Relay control cutout.
DC 12V to DC 5V conversion cutout.
ESP8266, muliplexer and voltage sensors
UPS mode detection
Microcontroler watch dog
