Solar System Health Checks & Performance Testing

Start with the inverter, because that is where a dead system usually shows itself. A green status light and a rising generation figure mean the array is producing. If your monitoring app shows generation tracking the weather across the day, the system is broadly healthy. What this will not tell you is whether one panel or one string has quietly dropped out, because the total can still look plausible while you lose a slice of output.

Your inverter display or monitoring portal gives daily and lifetime kWh. Compare a bright day this month against the same month last year rather than against a summer peak, since output is seasonal by design. A healthy system loses only a fraction of a percent a year, so a noticeable year-on-year drop on comparable days is a fault rather than age.

Open-circuit voltage and short-circuit current are the two readings, taken at the panel or string in daylight and compared against the values on the module label. It is a genuine test, but it means working on a live DC circuit, usually at height, and a healthy reading at the panel does not rule out a fault further down the string. It is the part of the job we would rather you left to us.

Once a year suits most domestic systems, and more often where there are trees, heavy soiling, coastal salt or a commercial array where downtime is expensive. If your system has never been checked and it is more than a few years old, that first inspection is usually the one that finds something.

A visual and structural inspection for cracks, discolouration and delamination, electrical testing of the inverter, wiring, fuses and breakers, performance testing that measures actual output against expected including thermal imaging for hotspots, and a shading and soiling assessment. You get a written report with the faults found and what we recommend doing about them.

Common signs are a red or amber status light, a fault code on the display, output that stops in the middle of the day and returns later, or a system that produces nothing at all while the panels themselves are fine. Note the exact code before switching anything off, because it tells us whether we are looking at a grid fault, an insulation fault or hardware failure.

It should support it. Some manufacturers require periodic maintenance to keep a warranty valid, and a documented inspection is evidence that the system has been looked after. A health check also identifies faults that are still inside a warranty period, which is often the difference between a free part and a paid one.

Yes. A large share of the systems we test were fitted by someone else, including installers who are no longer trading. We do not need to have installed it to measure it, report on it and take it on for future servicing.