What is a DC optimiser?

A DC optimiser sits between a single solar panel and the string that runs to your inverter. It monitors and conditions the voltage output from that panel, allowing it to operate at its maximum power point independently of neighboring panels. When one panel is shaded, dirty, or aged, a standard string inverter pulls the entire string down to match the weakest performer. A DC optimiser prevents this by letting each panel deliver its best output regardless of what happens next door.

Unlike a microinverter, which converts DC to AC right at the panel, a DC optimiser keeps the output as direct current and passes it to a string inverter for final conversion. This approach costs less than microinverters while avoiding the performance penalty of string-only systems. It is particularly useful in Perth Metropolitan installations where afternoon shading from buildings or trees affects portions of the array, or where panel orientation varies across the roof.

The device typically mounts on the DC rails behind each panel or in the combiner box. It draws minimal power itself and has no moving parts. For residential arrays with mixed sun exposure, DC optimisers offer a middle ground: better resilience to shading without the complexity or expense of full module-level power electronics.