When you browse through a LiFePO4 battery datasheet, you may notice codes like RS485, CAN, UN38.3, or IEC62619.
To most people, they look like random technical labels — but these standards and protocols define how safe, smart, and compatible a battery really is.
In short:
- UN38.3 and IEC62619 are safety certifications that ensure the battery won’t fail or catch fire.
- RS485, CAN, and RS232 are communication protocols that let the battery and inverter “talk” to each other.
Even a certified battery can cause system errors without proper communication.
This guide explains what these protocols mean, how they differ, and why they matter for every solar or UPS installation.
Certifications vs Communication Protocols
Before discussing communication, it’s important to understand that certifications and protocols serve completely different purposes.
Certifications ensure physical and electrical safety; protocols ensure intelligent control and coordination.
The table below highlights their differences:
| Category | Examples | Purpose | Verified By |
|---|---|---|---|
| Safety Certifications | UN38.3, IEC62619, UL1973, CE | Confirm safety under transport and operation | Independent testing labs (UL, TÜV, SGS) |
| Communication Protocols | RS485, CAN, RS232 | Enable data exchange between inverter and BMS | Implemented by manufacturer |
Certifications prove your battery is safe;
protocols ensure it is used safely within a working energy system.
Without both, the system may either be unsafe or simply fail to operate correctly.
What Is a Battery Communication Protocol?
A battery communication protocol is the digital language that connects a Battery Management System (BMS) to an inverter or energy management system (EMS).
Through this connection, the battery sends and receives key data such as:
| Data Shared | Function |
|---|---|
| Voltage and Current | Helps inverter adjust charging and discharging |
| Temperature | Prevents overheating or overcooling |
| SOC (State of Charge) | Displays accurate remaining energy |
| Fault and Warning Signals | Triggers inverter protection or shutdown |
Without this communication, the inverter cannot interpret the battery’s condition — resulting in wrong SOC display, unsafe operation, or system shutdown.
💡 Think of the protocol as a translator between the battery and inverter.
Different systems “speak” different languages; RS485, CAN, and RS232 are those languages.
Why These Protocols Exist?
These communication standards were not invented for batteries.
They came from the industrial and automotive sectors, where reliability and signal integrity were essential.
| Protocol | Developed By | Year | Original Purpose | Now Used In |
|---|---|---|---|---|
| RS232 | Electronic Industries Alliance (EIA) | 1960s | Computer serial connections | UPS, diagnostic tools |
| RS485 | EIA | 1983 | Industrial automation | UPS, telecom, solar BMS |
| CAN (Controller Area Network) | Bosch (Germany) | 1986 | Vehicle control and data network | EVs, hybrid inverters, LiFePO4 systems |
The reason the energy industry adopted them is simple — they are stable, proven, and compatible with noisy electrical environments such as solar or UPS systems.
What Is RS485?
RS485 is the most widely used communication interface in rack-mounted LiFePO4 batteries and UPS systems.
It allows one master (e.g., inverter or controller) to communicate with multiple batteries (slaves) over a single cable network.
| Specification | Typical Value |
|---|---|
| Communication Type | Half-duplex multi-drop |
| Distance | Up to 1200 meters |
| Baud Rate | 9,600–115,200 bps |
| Cable Type | Shielded twisted pair |
| Common Protocols | Modbus RTU, proprietary BMS formats |
RS485 excels in multi-battery setups, long cable runs, and industrial environments with electromagnetic noise.
It’s the go-to option for data centers, telecom racks, and commercial solar systems.
However, it requires correct wiring polarity and termination resistors (usually 120 Ω at both ends).
A mismatch often leads to the dreaded “BMS offline” error.
What Is CAN?
The CAN bus, originally designed by Bosch for cars, became the standard for smart inverters and EV batteries because of its speed and error-checking features.
| Specification | Typical Value |
|---|---|
| Communication Type | Real-time multi-master |
| Distance | ≤ 40 m (at 1 Mbps) |
| Speed | Up to 1 Mbps |
| Error Handling | CRC automatic correction |
| Applications | Solar hybrid inverters, EV packs, IoT devices |
CAN allows faster feedback — for example, an inverter can instantly adjust charging current when the battery’s temperature rises.
That’s why brands like Growatt, Deye, and Victron favor CAN communication for residential solar systems.
Unlike RS485, CAN requires that both the inverter and the battery use the same message structure (also called CAN mapping).
This is why inverter–battery compatibility matters so much.
What Is RS232?
RS232 is the simplest of all — a one-to-one serial connection between two devices.
It was used for computers decades ago and still appears in small UPS systems or factory diagnostics.
| Specification | Typical Value |
|---|---|
| Communication Type | Point-to-point |
| Distance | ≤ 15 m |
| Speed | ≤ 115,200 bps |
| Use Cases | Debugging, firmware update, small UPS |
| Pros | Simple, low cost |
| Cons | Short range, no multi-device support |
In modern systems, RS232 is mostly reserved for testing, logging, or maintenance, not for inverter communication.
Which One Should You Use?
Different applications benefit from different protocols.
Here’s a quick decision guide based on your scenario:
| Application | Recommended Protocol | Reason |
|---|---|---|
| Multi-rack or data center UPS | RS485 | Long distance, stable, multiple units |
| Hybrid inverter for solar home | CAN | Fast response and real-time control |
| Single UPS or testing setup | RS232 | Simple diagnostic communication |
If your inverter and battery are mismatched (e.g., inverter expects CAN, battery only supports RS485), communication will fail.
Always check the inverter manual for supported interfaces before purchasing a battery.
What Happens If a Battery Has No Communication Protocol
Even if a LiFePO4 battery is physically functional, lacking RS485 or CAN can cause serious issues:
- ❌ Inverter cannot detect or control charging
- ❌ SOC display is incorrect (e.g., 100% showing but only 60% left)
- ❌ Batteries in parallel operate unsynchronized
- ❌ BMS alarms are not transmitted to the inverter
- ❌ Risk of overcharge or deep discharge during off-grid operation
In short, the system can run, but not reliably.
Communication protocols are not optional — they are essential for safety and lifespan.
How Certifications and Protocols Work Together
While UN38.3 and IEC62619 prove a battery is safe by design,
RS485, CAN, and RS232 ensure it operates safely within a system.
| Layer | Example | Function |
|---|---|---|
| Safety Layer | UN38.3 (transport), IEC62619 (battery safety) | Protects against physical and electrical failure |
| Communication Layer | RS485, CAN, RS232 | Enables coordination and protection between inverter and BMS |
| System Layer | Inverter + EMS | Executes smart charging and monitoring |
So, if certifications make the battery “safe to exist,”
communication protocols make it “safe to work.”
Saftec’s Multi-Protocol and Certified Solution
Saftec LiFePO4 rack batteries combine both safety and intelligence:
- Certified to UN38.3 and IEC62619 for transport and system safety
- Equipped with RS485, RS232, and CAN ports for inverter compatibility
- Pre-tested with Growatt, Deye, Victron, and GoodWe inverters
- Supports up to 8 units parallel communication via RS485
- Optional CAN–Modbus auto-detection firmware
Before shipment, each Saftec battery undergoes a protocol simulation test to verify signal stability and inverter handshake success.
This ensures a plug-and-play experience for installers and OEM buyers.
The Future: From Wired to Cloud Communication
Battery communication is evolving toward smart, connected systems:
- Modbus-TCP (Ethernet) → for industrial remote dashboards
- MQTT / IoT → for real-time data logging and alerts
- CAN-MQTT gateways → linking on-site batteries to cloud monitoring platforms
Saftec is developing a cloud-based communication module that integrates RS485 and CAN data with an online monitoring system — allowing installers to view SOC, cycle count, and temperature remotely.
Conclusion
Battery communication protocols may not be official”certifications,” but they are just as vital.
While UN38.3 and IEC62619 guarantee a LiFePO4 battery is safe to ship and operate,
RS485, CAN, and RS232 guarantee that it runs efficiently, communicates accurately, and stays protected.
Without them, even the safest battery becomes blind.
With them, your storage system becomes a smart, coordinated network.
Saftec’s LiFePO4 rack batteries embody this principle — combining certified safety with multi-protocol intelligence for reliable energy systems worldwide.
