Your solar is producing a third of what it used to and the inverter isn't lying

Solar panels are famous for being maintenance-free, and the sentence everyone quotes skips the Nigerian addendum: dust, harmattan haze, cooking soot on the kitchen-side roof, and a mango that found its ambition at the panel's edge. A dirty panel loses output in silence - the system doesn't fault, it just earns less. This is the maintenance the marketing forgot.

The output evidence, before any climbing

Your inverter or charge controller is the instrument: log the same hour's production on three clear mornings, or read the app's history - a slow sawtooth decline with a rain-wash recovery is dirt; a hard step down after a storm is damage; the one-to-test is a partial shade pattern (a new shelf, the neighbour's antenna, the palm that was a seedling at installation). Dirt is a maintenance job; everything else on that list is a fault hunt. If the figures show nothing, the panel stays on the roof where the sun is keeping it honest and the inverter's history is the witness.

The cleaning rules that keep the warranty intact

• Rinse, then glide - never scrub. Soft cloth or a sponge on a pole, mild detergent only where there is grease. The glass is glass, but the edge seal is the vulnerable part: never a high-pressure washer, which drives water past the frame into the laminate, and never a dry scrub of gritty glass, which sands the coating and the panel at once.
• Cool glass, early morning. Panels straight-off-the-shelf at midday can crack under a cold pour - thermal shock is the one thing that breaks panel glass with no fault to show - and a wet panel in full sun dries into fresh water-spot mineral marks, so the dawn session is the only honest one.
• From the ground when possible; from the roof only when the roof is safe: the desk will not talk anyone onto a ladder - if the panels are beyond the eave-reach, the cleaning is a professional job with harnesses, and a good cleaning visit costs less than a single fall costs everyone. Walk the roof edge, check the feet: any rust bloom at a mounting foot or a lifted rail after a storm wind is a structural call, not a cleaning item.

The five-minute electrical glance (eyes off, hands off)

Look, do not touch: cable glands and any visible wiring for cracks, rodent chews and UV-brittle insulation - a chewed cable is not a "tape it" job, it is the DC fault that has started a roof fire; MC4 connectors and the inverter's DC isolator for a discoloured plastic (heat at a loose connection shows its colour before it shows its fault code); the inverter itself for its own ventilation - a box cooking in the sun room throttles its output, which reads exactly like dirty panels on the app, and the shade board or vent slot that fixes it costs the price of a piece of plywood.

The annual list

Wash at the harmattan's end; check the mount bolt torque when it is safe to reach (vibration loosens what the installer tightened); trim the shade at the panel line; re-run the same-hour three-morning test and compare with the last year's same-month figures; and read the battery room's smell and colour - a swollen battery case or a sulfurous tang means the whole page becomes moot because the battery person is now the first call, on the day, not the week.