If you're choosing solar electronics for a California ADU, the two main architectures are microinverters (one tiny inverter per panel) and string inverters (one central inverter for the whole array, usually paired with DC optimizers).
Microinverters convert each panel's DC output to AC right at the panel — every module is independent. String inverters wire panels in series, send the combined DC to a single inverter, then convert to AC at one location.
Microinverters handle shade per-panel: a shaded module doesn't drag down its neighbors. Plain string inverters suffer when one panel is shaded; SolarEdge-style optimizers close most of the gap but not all of it.
On a 2–4 kW ADU system, microinverters typically add $300–$700 vs a SolarEdge string + optimizer setup. On larger residential systems the cost gap narrows.
Enphase microinverters: 25-year warranty. SolarEdge inverter: 12-year (extendable). Microinverters distribute failure risk; string inverters concentrate it.
Not always. For unshaded, simple roofs on a tight budget, a SolarEdge string + optimizer setup is a strong value choice.
Microinverters — each new panel is independent. String inverters may need resizing.