Can clouds and cloudy weather explain consistently low solar output?

Partially — solar panels generate significantly less in overcast conditions, and Melbourne's winters are cloudier than summers. However, compare output on similar sunny days across different years to identify true underperformance vs weather variation.

My inverter is making a buzzing noise — is this normal?

A low-level hum from an inverter during normal operation is typical. Loud buzzing, clicking, or buzzing that intensifies before a fault code appears is not normal and warrants inspection by a solar electrician.

Homeowner symptom guide · Melbourne

Solar Panels Not Producing: Diagnosing the Problem

Many Melbourne homeowners only notice their solar system has stopped working when their electricity bill unexpectedly increases — by which point the system may have been non-functional for months. Understanding the most common causes of reduced or zero solar output helps you catch problems early and get the most from your investment.

Common Causes

• Inverter fault or shutdown: the inverter converts DC power from panels to AC power for your home. A fault code, thermal shutdown, or communication failure stops this conversion — the panels may still generate DC but none reaches your home.
• Panel soiling: heavy dust, bird droppings, or leaf debris on panels reduces the light reaching the cells. A single badly soiled panel in a series string can reduce output across the entire string.
• New shading: vegetation growth, a new neighbour's structure, or a new rooftop antenna can create shading on panels that previously had clear sun — often causing a dramatic reduction in output.
• Degraded panels: solar panels lose efficiency over time — typically 0.5–1% per year. After 10+ years, panels may be generating significantly less than their rated output, particularly if they have experienced thermal cycling or microfractures.
• Disconnected AC isolator or faulty DC isolator: isolator switches on the roof or at the inverter can fail or be accidentally switched off. This prevents generation without showing an obvious fault.

When to Be Concerned

⚠ No generation shown on the inverter display or monitoring app during clear sunny conditions
⚠ Generation is consistently more than 20% below historical averages for the same season
⚠ Inverter is showing a fault code or error light
⚠ Electricity bills have been increasing despite similar usage patterns

What to Do

1 Check the inverter display during peak sun hours — it should show active generation. Note any error codes.
2 Check that the AC isolator (typically next to the inverter) and the main DC isolator (typically on the roof or near the inverter) are both in the 'ON' position.
3 Check your monitoring data against historical averages for the same month in previous years.
4 If panels appear heavily soiled and you cannot safely access the roof, arrange professional cleaning.
5 Contact your installer or a Clean Energy Council accredited solar electrician for system inspection.

Frequently Asked Questions

Can clouds and cloudy weather explain consistently low solar output?

Partially — solar panels generate significantly less in overcast conditions, and Melbourne's winters are cloudier than summers. However, compare output on similar sunny days across different years to identify true underperformance vs weather variation.
My inverter is making a buzzing noise — is this normal?

A low-level hum from an inverter during normal operation is typical. Loud buzzing, clicking, or buzzing that intensifies before a fault code appears is not normal and warrants inspection by a solar electrician.

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