Everything You Need to Know About CAN Bus Data in Lithium Batteries
If you’re in the market for lithium battery systems—whether for electric bikes, AGVs, energy storage setups, or industrial equipment—you’ve probably heard of CAN bus. But do you know what data it transmits, and why that matters for your project’s safety, efficiency, and reliability?
For over 15 years, the Controller Area Network (CAN) bus has been the unsung hero of modern lithium battery management. It’s the “language” that connects a battery’s Brain—its Battery Management System (BMS)—to chargers, motor controllers, vehicle ECUs, and even remote monitoring tools. By transmitting real-time, structured data, CAN bus ensures seamless coordination between your battery and the rest of your system.
Let’s break down the critical data your lithium battery’s CAN bus is sending (and why you should care).
What Is CAN Bus Data in Lithium Batteries?
Simply put: CAN bus data is the structured set of messages your battery’s BMS shares with external devices. These messages include electrical measurements, safety alerts, control signals, and diagnostic logs—all optimized for high noise resistance and real-time communication (two must-haves for automotive and industrial environments).
Without this data, your battery would operate in a vacuum: chargers wouldn’t know when to stop, motor controllers couldn’t avoid overloading, and you’d have no way to spot potential failures before they happen.
Key Data Types Transmitted via CAN Bus
The CAN bus broadcasts dozens of parameters, but we’ve organized the most critical into four core categories:
1. Core Operating Data (The “Vitals” of Your Battery)
These are the real-time metrics that keep your system running smoothly. They’re transmitted most frequently (some as often as every 10–50 milliseconds!) because timing is everything for performance and safety.
- Voltage Data: Total battery pack voltage, minimum/maximum cell voltage, and voltage imbalance status. Prevents overvoltage/undervoltage damage and ensures cells charge/discharge evenly.
- Current Data: Real-time charging/discharging current, peak current readings, and short-term pulse current capacity. Keeps motor controllers within safe limits.
- Temperature Data: Cell temperatures (from multiple sensors), MOSFET/PCB temperatures, ambient temperature, and redundant thermal data. Temperature is lithium batteries’ #1 safety risk—this data stops overheating or freezing.
- State of Charge (SOC): Remaining capacity (%), absolute capacity (Ah), and estimated range (for e-vehicles). Lets chargers use the right charging curve and helps users plan trips.
- State of Health (SOH): Battery degradation level, internal resistance trends, and cycle count. The foundation of predictive maintenance—so you can replace batteries before they fail.
2. Safety & Protection Data (Your Battery’s “Early Warning System”)
Lithium batteries are safe when properly monitored—and CAN bus is the first line of defense against hazards.
- Protection Events: Alerts for critical issues like overvoltage/undervoltage, overcurrent (charging/discharging), short circuits, extreme temperatures, or cell imbalance. Triggers immediate system shutdown if needed.
- Fault & Error Flags: Warning/severity levels, error IDs for troubleshooting, and continuous fault logging. Lets service teams diagnose problems quickly (no guesswork!).
3. Power Control & System-Level Data (Coordination Is Key)
CAN bus doesn’t just “report”—it “commands,” ensuring your battery works in sync with other components.
- Power Limits: Maximum allowed charging/discharging power, plus dynamic derating based on temperature or SOH. Prevents overheating during high-load use (e.g., climbing hills on an e-bike).
- Charging Status: Charging mode (slow/fast, constant current/voltage), completion status, and BMS-charger communication feedback. Guarantees safe, efficient charging every time.
- Discharge & Motor Control: Recommended torque/power limits, current output permissions, and controller interlock signals. Keeps batteries and motors working in harmony.
4. Advanced Diagnostic Data (For Long-Term Reliability)
OEMs and maintenance teams rely on this data to reduce costs and enable remote troubleshooting:
- UDS/ISO 14229 diagnostic services
- Event logs and historical faults
- EEPROM-based BMS log recovery
- OTA update-compatible data fields
Data Frequency & Frame Structure
Not all CAN data is transmitted equally—frequency depends on how critical the metric is:
- High-frequency (10–50ms): Voltage, current, temperature (real-time safety data)
- Medium-frequency (100–500ms): SOC, SOH (performance/health updates)
- Low-frequency (1–2s): System status, diagnostic indicators (non-urgent insights)
BMS systems also use different CAN protocols, depending on the application:
- Custom CAN: Most common for e-bikes and e-scooters (flexible for small-scale systems)
- CANopen: Popular for industrial equipment and robotics
- J1939: Standard for heavy-duty vehicles and large-scale energy storage
Curious which protocol is right for your project? Check out our guide: CANopen, J1939, or Custom CAN: Which Fits Your Lithium Battery Application?
Real-World Applications: How CAN Data Powers Your Device
CAN bus data isn’t just technical—it’s practical. Here’s how it’s used in key industries:
- E-Bikes & E-Scooters: Optimizes motor torque for better acceleration, improves range predictions, and monitors temperature to prevent overheating during long rides.
- AGVs & Robotics: Enables fleet-wide status tracking, smart charging (no overcharging!), and predictive maintenance (replace batteries before they die mid-shift).
- Energy Storage & Industrial Equipment: Triggers remote alarms for faults, balances power loads across systems, and enforces safety interlocks to protect workers.
Why This Matters for You
Whether you’re an OEM building products, a buyer sourcing batteries, or an engineer optimizing systems, understanding CAN bus data helps you:
- Ensure safety (avoid catastrophic failures)
- Boost efficiency (longer battery life, better performance)
- Reduce maintenance costs (predict issues before they escalate)
- Verify compatibility (make sure your battery works with your existing components)
At Tritek Battery, our lithium battery systems are built with transparent, reliable CAN bus communication—so you always have full visibility into your battery’s performance. We support custom CAN protocols, CANopen, and J1939, and our BMS transmits all the critical data you need to build smarter, safer products.
Ready to Learn More?
Want to dive deeper into CAN bus protocols, or need help selecting a lithium battery system with the right CAN data capabilities? Contact our team today—we’re here to help you optimize your project for performance and reliability.