F13 on a Sunsynk ECCO single-phase hybrid SG05LP1: Working mode change - grid type/frequency changed, battery mode set to 'No battery', or (old firmware) system work mode changed

What it means

The manual says: Working mode change - grid type/frequency changed, battery mode set to 'No battery', or (old firmware) system work mode changed.

Part involved: operating mode.

When it shows: Mode/setting change or grid event.

Likely causes:

• Grid loss or reconnection; grid type or frequency changed; battery mode changed to 'No battery'; major settings change; old firmware reports it on any work-mode change.

Is it safe?

The inverter keeps running with some functions stopped.

Resetting itself: yes.

Manual reset: Generally disappears automatically; if not, DC and AC switches off, wait one minute, on.

What you can check

• Read the full code and message on the inverter screen or in the Sunsynk Connect app and note the date/time for your installer.
• Check the inverter's AC isolator next to the inverter and the solar/battery breaker in the consumer unit are ON (do not reset a breaker that trips again - call your installer).
• F13 usually clears by itself after a settings change or grid blip - check if anyone changed settings in the app.
• Sunsynk's documented restart: turn off the inverter's DC and AC switches, wait one minute, turn back on - only do this if your installer has shown you the safe shutdown/restart sequence; otherwise ask them.

What the engineer will check

• Review settings history; update firmware; check grid sensing.

Who to ask for: Qualified electrician / MCS PV installer.

Certification: Firmware/config change via installer portal; no special certification but installer access normally required.

What you might notice

• Error code shown on inverter or app

Sources

• Fault Codes Causes & Solutions Version 1.0 ↗ · Version 1.0 · page 5 · Reviewed 24 September 2026

A code explains what the controller detected, not a confirmed root cause.

Reviewed: 24 September 2026