When I first connected a lithium battery to a hybrid inverter, I didn’t realize communication mattered that much. But after experiencing charging errors and missing data, I learned that CAN and RS485 protocols are essential for battery-inverter integration in PV systems.
CAN and RS485 communication allow the battery and inverter to exchange real-time data, improving safety, performance, and energy efficiency. Without proper communication, your system may misread battery status, shorten battery life, or trigger unnecessary shutdowns.
Let’s explore how these two communication protocols work and why they matter.
Why Is Communication Important in Battery-Inverter Systems?
Communication ensures the inverter knows the battery’s real-time voltage, current, temperature, and SoC (State of Charge). This enables accurate charging, safe discharging, and intelligent control.
Key Functions Enabled by Communication:
- Battery status monitoring
- Charge/discharge current control
- Temperature-based protection
- State of Health (SoH) tracking
- Remote firmware upgrades
Without this communication, the inverter operates blindly—just relying on voltage, which is risky.
What Is RS485 Communication in Lithium Battery Systems?
RS485 is a serial communication protocol used to transmit data over long distances with high reliability. It supports multi-device networks with a master-slave architecture.
In PV systems, RS485 allows the inverter to communicate with multiple batteries or BMS controllers.
Features of RS485:
- Long cable range (up to 1,200 meters)
- Noise-resistant and suitable for harsh environments
- Widely supported by commercial and residential inverters
Common Use Case:
- Connecting multiple lithium battery modules in series or parallel to a central inverter/BMS
What Is CAN Communication in Lithium Battery Systems?
CAN (Controller Area Network) is a fast, high-priority communication protocol widely used in automotive and industrial systems. It supports real-time, high-speed data exchange.
In battery systems, CAN allows more advanced data handling, especially in high-voltage or EV-style battery banks.
Features of CAN:
- Fast transmission speed (up to 1 Mbps)
- Real-time priority-based data
- Robust error detection
- Shorter cable range (usually under 40m)
Typical Applications:
- Communication between BMS and inverter in smart lithium batteries
- EV battery packs
- Industrial energy storage
Comparison Table: CAN vs RS485 in Battery-Inverter Systems
| Feature | RS485 | CAN |
|---|---|---|
| Speed | Moderate (up to 115kbps) | High-speed (up to 1Mbps) |
| Topology | Master-Slave | Multi-Master (peer-to-peer) |
| Range | Up to 1,200m | Typically under 40m |
| Use Case | Basic battery communication | Advanced BMS + inverter control |
| Error Handling | Basic | Advanced error detection |
| Real-Time Prioritization | No | Yes |
Choose RS485 if you need distance and simplicity. Choose CAN for speed, accuracy, and smart control.
Do I Need CAN or RS485 for My System?
Check your inverter and battery specs. Some models support both CAN and RS485, while others are limited to one. For example:
- Hybrid inverters: Often support both
- Grid-tied inverters: May not require BMS communication
- Off-grid systems: Prefer CAN for dynamic control
Ask your supplier for a communication protocol list and firmware compatibility.
Conclusion
Whether you're setting up a residential solar system or designing a large ESS project, proper CAN or RS485 communication between lithium batteries and inverters is critical for safety, efficiency, and long-term system health.
At SANKE, we offer full communication support—our lithium batteries are compatible with major inverter brands via both CAN and RS485, ensuring seamless and smart integration for every solar project.
FAQs
What is RS-485 communication function?
RS-485 enables serial communication between devices over long distances, supporting multi-device networks with reliable data transfer.
What is CAN communication in battery?
CAN allows real-time communication between the battery’s BMS and other devices like inverters, offering fast and accurate control of battery behavior.
What is the difference between RS-485 and CAN communication?
RS-485 is slower but supports longer distances. CAN is faster and better at handling real-time data with built-in error correction.
What is a RS-485 port used for?
An RS-485 port is used to connect devices like inverters, BMS, or controllers to exchange serial data, especially over extended wiring distances.
