How do I clear or fix error E18?

Verify the communication cable (CAN/RS485/Modbus) is correctly seated and the right pinout is used. Check baud rate and protocol settings in both devices match.

E18

Felicity inverter error E18

SPI Comm Fault

Fault — the inverter cuts its output and the red LED stays solid until the fault is cleared.

E-CHO-SI3KS2

InverterFault

Also applies to:E-CHO-SI5KS2E-CHO-SI8KS2

What it means

SPI Comm Fault — SPI internal communication fault.

Cause: Communication has been lost between the inverter and a peripheral device — typically a battery BMS, smart meter, or external monitoring dongle.

How to fix it

Verify the communication cable (CAN/RS485/Modbus) is correctly seated and the right pinout is used.
Check baud rate and protocol settings in both devices match.
Reseat the dongle/comms module.
For BMS comms, confirm the battery is powered on and not in deep-discharge protection.

Source: E-CHO-SI3KS2-Operation-Manual.pdf, p.16 · E-CHO-SI5KS2-Operation-Manual.pdf · E-CHO-SI8KS2-Operation-Manual.pdf

Frequently asked questions

What does error E18 mean on a Felicity inverter?: E18 means: SPI Comm Fault. Communication has been lost between the inverter and a peripheral device — typically a battery BMS, smart meter, or external monitoring dongle.
Is error E18 a fault or a warning?: E18 is a fault code: the inverter cuts its output and the red LED stays solid until it is cleared.
How do I clear or fix error E18?: Verify the communication cable (CAN/RS485/Modbus) is correctly seated and the right pinout is used. Check baud rate and protocol settings in both devices match.

Related error codes

Other codes on the E-CHO-SI3KS2

All E-CHO-SI3KS2 codes All E-CHO-SI5KS2 codes All E-CHO-SI8KS2 codes

Prefer the full written guide? Read the complete Felicity inverter error-code guide

Compiled from official Felicity user manuals. Always consult your device manual and a qualified technician before performing repairs.