The yearly service of a solar installation in six checks

Photovoltaics have no moving parts, which is where the reputation for "zero maintenance" comes from. The truth is more nuanced: the connections do age. An hour of checking every spring avoids the great majority of the repairs that reach us.

Start with a visual inspection of the modules. Look for cracks in the glass, burn marks around the junction boxes and yellowing of the encapsulant. Clean water and a soft brush are enough; avoid a pressure washer, which can force water past the seals of the junction box.

Next, check that the battery connections are tightened to the recommended torque. A loose terminal heats up, oxidises and eventually melts. It is the most common failure and the easiest one to prevent. While you are there, inspect the lugs for green discolouration or white powder.

Check the condition of the exposed MC4 connectors. Open a few of them with the keys made for the job and make sure no moisture has found its way inside. A connector holding water has to be replaced, not dried out and put back.

Finally, read the annual production off your controller or your inverter and compare it with the previous year. A drop of more than 5% that the weather does not explain deserves a diagnosis. While you are at it, check the surge protector indicator in your combiner box: the cartridge is consumed over time and replacing it costs a fraction of the price of an inverter.

If a reading worries you, write to us at info@sol-air-tech.com with your figures. We can often identify the cause remotely.