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Usually self-clears

Sunsynk F13: Working / Grid Mode Changed

Updated June 2026 · Reviewed for technical accuracy · ~2 min read

F13 is one of the friendliest codes your Sunsynk can show. It simply means the inverter noticed that its working mode or grid type changed, and it is flagging that it adjusted. Most of the time it clears on its own within a minute. It often pops up right after a setting is changed in the SunSynk Connect app or on the screen.

What sets off F13

  • A setting you or your installer changed, such as grid type, frequency, work mode or battery mode.
  • A grid condition the inverter adapted to.
  • A normal mode switch on a hybrid system, for example moving between selling, self-use and backup.

What to do

  1. Give it a minute. F13 usually clears by itself once the new mode settles in.
  2. If it lingers, power-cycle. Turn the DC isolator and AC breaker off for a minute, then back on.
  3. Check your settings match what you want. Confirm the grid type and work mode are set the way your system should run. If you changed nothing and it keeps reappearing, make a note of when it happens.
Good news F13 is informational, not a hardware fault. On its own it does not mean anything is broken. It only needs a look if it repeats without any setting change.

Related Sunsynk codes

F35, No AC grid F41, Parallel system stop F58, Battery comms fault

FAQ

Should I worry about F13?

Almost never. It is the inverter reporting a mode or grid change, and it usually clears within a minute. Only investigate if it repeats without you changing anything.

F13 shows every day. Is that normal?

Repeated F13 with no setting change can point to an unstable grid or a configuration that keeps flipping modes. It is worth asking your installer to review the work-mode settings.

Sources

  • Sunsynk Hybrid Inverter User Manual (F13 = working mode change; grid type/frequency or battery mode altered, restart if unresolved).
  • Sunsynk fault-code references and installer documentation.
⚠️ Safety disclaimer. Solar inverters carry lethal DC and AC voltage even when "off". This guide covers external, switch-level steps only. Never open the unit or work on wiring unless qualified. When in doubt, call a licensed installer or electrician.