Solis Battery BMS Comm Fault Fix Ireland: CAN & Pinouts

Key Takeaways

• The CAN Comm Fail alarm indicates a communication failure on the CAN bus, preventing the inverter from exchanging data with the battery management system.
• A No Battery alarm occurs when the inverter detects zero battery presence due to disconnected cabling, powered-off packs, or configuration errors.
• BYD high-voltage battery links require dedicated Cat6 or higher communication cabling with battery side pin 1 and 2 mapped to inverter side pin 4 and 5.
• Verifying that the CAN connection is properly earthed prevents ground loops and electrical interference from corrupting digital data.
• Safe Electric regulations in Ireland mandate dual-source isolation and an external 2 pole AC isolator switching live and neutral.

Why is my Solis inverter showing CAN Comm Fail or No Battery?

When an energy storage system triggers a communication fault in Ireland, the hybrid inverter cannot read cell state of charge, temperature, or voltage limits. Without real-time telemetry from the battery management system (BMS), the inverter immediately halts charging and discharging to prevent battery damage.

Ginlong Solis hybrid systems display two interrelated alarms for this condition:

1. CAN Comm Fail (or Batt_Comm_FAIL): This error indicates a communication failure on the CAN controller area network bus, meaning the inverter is unable to establish a proper connection with the battery management system.
2. No Battery: This error means the inverter is not detecting any connected battery. It could be due to disconnected or faulty cables, a powered off battery, or incorrect inverter configuration settings. Often, a No Battery warning appears as a follow-up alarm immediately after an unresolved CAN communication failure.

Diagnosing these alarms requires systematic verification of battery power status, physical cable pinouts, bus voltages, and termination resistors.

Pylontech Diagnostic and Telemetry Cross-Check

For popular low-voltage storage modules such as the Pylontech US2000C, US3000C, and US5000, initial triage begins with checking communication between the inverter and the battery to ensure that the inverter is properly communicating.

If the inverter displays zero voltage or significantly divergent numbers, the BMS has stopped broadcasting valid data packets over the communication link.

BYD High Voltage Battery & Pinout Verification

Connecting high-voltage lithium storage, such as BYD Battery-Box Premium systems, requires adherence to specific wiring pinouts and conductor standards.

```
[BYD Battery Side] [Solis Inverter Side]
Pin 1 ------------------------------> Pin 4 (CAN High)
Pin 2 ------------------------------> Pin 5 (CAN Low)
Shield / Drain ---------------------> Earth Grounding Terminal
```

Installers must make sure that the CAN cable used is Cat6 or above and that the cable provided with the standard S6 device is not suitable for BYD connection. Using incorrect patch leads causes immediate bus timeouts.

Pinout Mapping and Inverter Port Voltage Test

BYD communication relies on specific differential pairs:

• Ensure communication pinout alignment: battery side pin 1 and 2 must connect to inverter side pin 4 and 5.
• To check if the inverter is ready to communicate, measure 2.1V between pin 2 and pin 4 or 5 on the inverter communication port using a multimeter.
• Always verify that the CAN connection is properly earthed to prevent grounding issues and electrical noise interference.

Visual Blink Codes & Reconnection Timeline

During initial commissioning or after clearing a fault, observe the LED blink code on the BYD battery. The blink code on the battery should display 11 times in blue and one time in white if it is ready to communicate.

Following any reconfiguration, cycle the system power. After the restart, it can take up to 15 min if the battery is recognized for the first time. Installers should wait for at least 2 minutes before proceeding to switch the system back on during reboot sequences.

CAN Bus Termination Resistor Requirements

On installations involving Solis S6 hybrid models (such as the S6-EH3P series), signal reflections along the serial bus can distort CAN data packets. Ginlong engineering guidelines specify:

• Even with a single battery installation or multi battery installation, a COM resistor is required to strengthen the CAN bus signal.
• Ensure the supplied COM termination resistor plug is correctly seated in the auxiliary communication terminal to prevent signal dropouts.

Safe Electric Standards & Irish Installation Compliance

Inspecting and testing communication cabling on residential energy storage systems in Ireland must follow national safety regulations.

Safe Electric & I.S. 10101 Safety Notice: Energy storage systems combine high DC battery voltages with mains AC utility supplies. Always isolate AC and DC isolation switches before touching terminals or opening wiring compartments. Work inside the inverter casing or main distribution board must be completed by a Safe Electric Registered Electrical Contractor (REC).

Under the Sustainable Energy Authority of Ireland (SEAI) Domestic Solar PV Code of Practice:

• Safety Compliance: Inverters must meet the requirements of EN 62109 and comply with EN50549.
• National Wiring Rules: All electrical circuitry must comply with NSAI I.S. 10101 wiring rules and demonstrate a minimum inverter rated efficiency of 95 percent.
• Mandatory Warning Signage: A durable warning placard stating "Inverter Isolate AC and DC before carrying out work" must be clearly visible on the inverter exterior.
• AC Isolation: An AC isolator 2 pole switching live and neutral must be installed between the inverter and the consumer unit.

By verifying Cat6 cable integrity, confirming correct RJ45 pinout mappings, checking bus termination resistors, and adhering to Safe Electric standards, homeowners and installers can resolve Solis battery communication faults and maintain reliable microgeneration storage.