Solar system stopped generating? What to check first in Perth

Your solar monitoring app shows zero output, or you've noticed your electricity meter running forward despite a sunny day. Before calling your installer, work through these checks in order — the large majority of zero-generation cases are caused by something you can resolve yourself in 10 minutes.

Check 1 — Is it actually a grid outage?

Standard grid-tied solar inverters shut down automatically during a grid outage. This is a safety requirement — if your inverter kept generating during an outage, it would energise a supposedly dead power line that a Western Power technician might be working on.

How to check: Look for any other signs of mains power failure in your home (clocks resetting, other appliances off, neighbours' homes without power). Check if your lights and appliances work normally. If you have no mains power at all, the solar being offline is correct behaviour — it will resume generating automatically when the grid is restored.

If you have a battery with EPS (Emergency Power Supply) mode, it may be powering part of your home during the outage — but the solar inverter itself will still be offline until grid is restored.

Check 2 — Check the inverter display

Walk to where your inverter is installed (typically on an exterior wall near the switchboard or in the garage). Most inverters have a display panel or LED indicators:

Green light / "Normal" display: The inverter is running normally. If output is still showing zero in your app, the issue is likely your monitoring connection (see Check 5), not the inverter itself.

Red or orange fault light: The inverter has detected a fault. Note the fault code displayed (a number or letter-number combination like "F13" or "Grid Volt High"). This is the starting point for diagnosis.

Display blank / no lights: The inverter has no power. Check the AC isolator switch (see Check 3).

Common display messages that are not serious faults:

• "No grid" / "Grid disconnected" — grid outage or temporarily out of range
• "Wait" / "Initialising" — inverter is in the 5-minute reconnection delay after a grid disturbance (required by AS4777.2); will return to normal automatically
• "Grid Freq High/Low" — grid frequency out of range; inverter automatically reconnects when frequency normalises

Check 3 — Check the AC isolator switch

Every solar inverter has an AC isolator switch mounted nearby (a white or red switch in a weatherproof enclosure, typically labelled "Solar AC Isolator" or "PV AC Disconnect"). It must be in the ON position for the inverter to operate.

Common reasons it's off:

• Tripped due to a fault
• Someone switched it off during maintenance or was unfamiliar with it
• A storm surge caused a trip

If you find it in the OFF position, switch it back to ON and wait 5 minutes for the inverter to reconnect. If it trips off again within a few minutes of resetting, there is a wiring fault — do not keep resetting it; call your installer.

Check 4 — Check the switchboard

Your switchboard has a dedicated circuit breaker for your solar system. Common labels: "Solar," "PV," "Inverter," or your installer may have labelled it with the inverter brand.

If the solar circuit breaker has tripped (the toggle is in the middle position or the OFF position), reset it to ON. If it trips again, there is a fault requiring an electrician or your installer.

Also check whether the main circuit breaker (the largest switch in the board) has tripped. A main breaker trip cuts power to the inverter as well.

Check 5 — Is the monitoring offline but the inverter still generating?

Some homeowners notice "zero generation" in their app, but the inverter is actually working fine — the monitoring connection has dropped out. This can happen if:

• The Wi-Fi router was changed or the password updated
• The inverter's Wi-Fi dongle lost connection during a router firmware update
• The monitoring datalogger has a low battery (for battery-backed loggers in some older systems)

How to tell: Walk to the inverter and look at the display. If it shows a normal output reading (e.g., "3.2 kW") but your app shows zero, the inverter is generating but not reporting. This is a monitoring issue, not a generation issue — your system is working fine.

For Wi-Fi monitoring: Most inverter apps (SolarEdge, Sungrow, Fronius, Goodwe, GrowWatt) have a reconnection guide in their support documentation. Usually this involves pressing a reset button on the Wi-Fi dongle and re-entering your Wi-Fi credentials.

Check 6 — Is it a morning/evening low-light situation?

Solar inverters have a minimum voltage threshold before they start generating. In early morning (before about 7:30am in winter) or late afternoon (after about 4:30pm in winter), irradiance may be too low to reach the inverter's start threshold even on a clear day.

A system that shows zero generation at 7:00am in July in Perth is behaving normally. Peak generation hours in Perth are typically 9am–3pm year-round, 8am–4pm in summer.

Check 7 — Is output low rather than zero?

If your system is generating but at significantly lower output than expected, consider:

• Clouds or haze: Output on cloudy days may be 20–50% of full capacity. Check the weather forecast and compare against expected output for clear vs overcast conditions.
• Soiling: Bird droppings or heavy dust on panels can reduce output 5–15%.
• Shading: A new structure, grown tree, or new neighbouring building may be casting shade on your panels. Compare against same-date output from the previous year.
• Shade from the ridge cap or parapet: Early morning and late afternoon shade is normal; if shading is occurring at midday, investigate the source.

When to call your installer

Call after exhausting the checks above if:

• The AC isolator or switchboard breaker keeps tripping
• The inverter displays a specific fault code that won't clear
• The inverter display is blank with all switches confirmed ON
• Output has been consistently 30%+ below historical for more than a week without an obvious cause

When calling, have ready: your inverter make/model (on the label on the inverter), the fault code displayed (if any), and what you checked from this list. This significantly speeds up diagnosis.

For inverters within the manufacturer warranty period (typically 5–10 years), your installer can raise a warranty service request with the manufacturer.

In Perth conditions, the most common zero-generation causes in order of frequency: (1) grid outage with automatic shutdown; (2) inverter in reconnection delay after a grid disturbance; (3) AC isolator switched off. Most cases resolve within 10–30 minutes without any service call.