Summary

The BOS-B modular lithium-ion battery energy storage system is designed for commercial and industrial backup power applications. In this architecture, Ethernet networking—implemented with a WIZnet W5500 controller—enables remote monitoring, fault detection, and system communication between the battery management system (BMS), controllers, and external monitoring infrastructure. The Ethernet interface allows reliable TCP-based diagnostics and monitoring for large-scale energy storage deployments.

This image was created by Gemini.

Solar Panels: Installed on the roof, they absorb sunlight and produce direct current (DC) electricity.

Solar Inverter: Converts the DC electricity produced by the panels into alternating current (AC) electricity for household use.

Lithium-ion Battery System: Stores surplus power generated during the day for use at night or on cloudy days.

Battery Management System (BMS): Monitors and safely manages the charge and discharge status of the batteries.

Grid: Receives power when solar power generation is insufficient or transmits surplus power.

What the Project Does

The BOS-B system is a modular lithium-ion battery energy storage system (ESS) used for applications such as:

commercial backup power

renewable energy integration

load shifting and peak shaving

industrial facility energy stabilization

Each battery module provides 14.3 kWh capacity, and up to 15 modules can be connected in series, allowing systems to scale up to 214.5 kWh total energy capacity.

The system architecture includes:

Battery Modules

Each module contains:

lithium-ion battery cells

integrated cooling fan

BMS monitoring electronics

communication interface

High-Voltage Control Box

The control unit aggregates battery clusters and provides:

system monitoring

high-voltage switching

communication with external devices

display and fault reporting

External System Integration

The ESS communicates with inverters and monitoring systems using multiple interfaces:

CAN for battery management communication

RS485 for industrial device integration

TCP Ethernet networking for remote monitoring and diagnostics

Where WIZnet Fits

The system includes Ethernet networking capability implemented using the WIZnet W5500 Ethernet controller.

Evidence appears in the system fault-handling logic where the firmware explicitly detects Ethernet chip communication errors:

Fault code example

This indicates that the controller communicates with a W5500 Ethernet chip over SPI and monitors its operational state.

Role of the W5500

In this ESS architecture, the W5500 provides:

hardware TCP/IP stack

Ethernet connectivity for monitoring systems

reliable network communication independent of the main MCU load

Because the TCP/IP stack runs inside the W5500 hardware, the system controller can focus on:

BMS data processing

battery safety monitoring

fault detection

inverter communication

This architecture is particularly useful in industrial environments where deterministic and stable communication is required.

Practical Tips / Pitfalls

Ensure stable SPI wiring between the MCU and W5500 to prevent communication faults.

Industrial ESS environments often contain EMI; proper grounding and shielding are critical.

Monitor W5500 link status to detect Ethernet cable disconnection.

Use static IP configuration when integrating with industrial SCADA systems.

Validate socket buffer configuration to support multiple simultaneous monitoring connections.

Implement watchdog supervision for network tasks to maintain reliability.

FAQ

Why is W5500 used in this system?

The W5500 provides a hardware TCP/IP stack that offloads networking tasks from the system MCU. This reduces CPU usage and improves communication reliability in industrial energy storage controllers.

How does the controller connect to the W5500?

The W5500 communicates with the controller through an SPI interface. The MCU exchanges network packets and configuration commands via SPI registers.

What role does the W5500 play in this ESS project?

It enables Ethernet-based monitoring and remote diagnostics for the battery system, allowing operators to view system status, fault codes, and performance metrics over a network.

Can beginners reproduce this architecture?

The basic Ethernet interface using W5500 is accessible to intermediate embedded developers. However, a full ESS system involves high-voltage battery management and industrial safety requirements.

How does W5500 compare to Wi-Fi solutions?

Industrial battery systems typically prefer wired Ethernet because it provides deterministic latency, higher reliability, and immunity to wireless interference in electrically noisy environments.