Solar Panel Cleaning in Cairns

Soiling costs output, and not in proportion

An array in Far North Queensland rarely fails outright. It fades. Production slips a few per cent at a time across a couple of wet seasons and nobody notices, because nothing alarms for a panel that is merely dirty.

What settles on the glass here is specific. Fine dust off dry season roads and paddocks. Cane ash through the burn season out toward Gordonvale and the Mulgrave, which lands as a greasy film rather than loose grit. Salt aerosol on anything within a few streets of the water. Bird mess, which is the worst of it, because it is opaque and rain does not shift it.

Then there is the edge growth. Every panel sits in an aluminium frame that stands proud of the glass, and that lip holds water along the bottom edge after every shower. In this humidity the damp line grows algae, then lichen, and it creeps inward across the lowest row of cells.

Why a band across the bottom row matters

Cells inside a panel are wired in series, so the current through the string is limited by the worst cell in it. A continuous band of soiling across the bottom row does not cost you the small percentage of area it covers. It throttles the whole string behind it. Bypass diodes cap the damage at roughly a third of the panel, which is still far more than the dirt looks worth.

That is why a panel that appears only slightly grubby can be measurably down, and why the frame line gets the attention rather than the middle of the glass. Rain handles the middle reasonably well if the pitch is decent. Most Cairns roofs sit around 15 to 22 degrees. Below about 10 degrees, rain sheets across instead of running off, and the array stops self cleaning almost entirely.

The method, and what it rules out

Panels get deionised water and a soft bristle brush on a pole, worked early while the glass is still cool.

Nothing else goes near them. No high pressure, because the frame seal and the junction box behind it were never designed to take a lance, and water forced past that seal ends up in the laminate. No acids or strong detergents, because the glass carries a thin anti reflective coating that hazes permanently once it is etched. No tap water either. Local supply leaves a mineral film as it dries, and that film becomes the next layer of soiling.

Access gets planned properly, harnessed, and off the panels. Standing on glass produces cell microcracks that are invisible on the day and show up as hotspots later. While we are up there you will get an opinion on the roof itself, since lichen around an array usually means lichen on the roof too.

When washing will not help

If output dropped suddenly rather than drifting down over seasons, it is not dirt. A dead string, a tripped isolator or a failed optimiser all read as a production problem, and none of them are fixed with water. Get an electrician to the inverter first.

If the array is well pitched, clear of overhanging trees, and has just come through a full wet season, it may already be as clean as washing will make it. We will say so rather than book you in.

Call 07 4028 4268 or send a photo of the array through the quote form.