Solar Panel Maintenance and Servicing

What actually wears out

The modules are the most durable part of a solar installation. Glass, aluminium and encapsulated silicon sitting still in the weather age slowly and predictably. Everything attached to them ages faster.

A service is aimed at those parts: the connectors, the isolators, the fixings, the inverter and the monitoring. Cleaning the glass is a separate activity, and it is the one people ask about most and the one that matters least.

The array and its fixings

We start on the roof or at the frame, looking at the modules themselves. Cracked glass, delamination where moisture has got into the laminate, discolouration of the encapsulant, snail trails, and any damage to the backsheet are all recorded photographically so that the next service has something to compare against.

Then the fixings. Clamps loosen, rails move, and thermal cycling over years works at every mechanical joint. We check clamp torque against the mounting manufacturer’s figure rather than by feel, and look at rail splices, end clamps and the roof hooks where they can be seen.

The DC side

This is where the interesting faults live.

• Connectors. Plug-in DC connectors are reliable when they are the same make on both sides and properly crimped. Where two different manufacturers’ connectors have been mated — which happens more than it should — the contact pressure is wrong, resistance rises, and the joint heats. We look for discolouration and heat marking at every accessible connection.
• Cable. DC cable is UV-stable but not indestructible. Cable left resting on a tile edge, or looped under an array where a bird has been at it, fails eventually.
• Isolators. Rooftop DC isolators live outdoors in a plastic box and are a known source of water ingress. Any sign of moisture inside one is treated as a defect, not an observation.

Testing

Visual inspection tells you about the things you can see. Testing tells you about the rest.

We measure open-circuit voltage and operating current for each string, and compare them against each other and against the design figures corrected for conditions. A string producing meaningfully less than its twin has a reason, and the reason is worth finding.

Insulation resistance testing checks the DC circuit against earth. Earthing and bonding continuity is verified. Where optimisers or microinverters are fitted, per-panel data gives a far more precise picture and we review it panel by panel.

The inverter and battery

Inverters are the hardest-working component in the system and the one most likely to need replacing during the array’s life. We check the fault and event log rather than just the front panel, look at the cooling path and any filters, confirm firmware status, and check the mounting environment — an inverter in an unventilated loft in August is being asked to work in conditions it will not enjoy.

Where there is a battery, we review cycle count, throughput, state of health where the system reports it, and whether the charge and discharge schedules still match the tariff you are actually on. Tariffs change more often than equipment does.

What you get

A written report with photographs, the test results, anything that needs attention now, anything worth watching, and a clear statement of what we did not or could not inspect. Where remedial work is needed we quote it separately so you can decide.