String inverter vs MLPE under partial shade: calculator

String inverter vs MLPE under partial shade

One series string of 300 W modules, each with 3 bypass diodes (20 cells per diode). Instantaneous power at 25 °C cell temperature, not annual energy. An illustration from a simple bypass-diode model, not a vendor result.

Presets (12 modules, the page's worked example)

Array Modules in the string (2 to 30) Optimiser conversion loss, % of module power (0 to 10)

Shaded groups (modules not listed get full light)

Modules in group

Shaded diode sections (0 to 3)

Light on those sections, % (1 to 100)

Layout	DC power (W)	Against modules' own peaks

Assumptions: identical modules (CEC database record CS6K_300M, SAM 2018.11.11), bypass diode clamps a section at -0.5 V, an ideal global-maximum tracker, the same inverter efficiency in every case, no wiring loss, inverter voltage window ignored. Light scales the irradiance on a section. Optimisers carry the loss entered above; microinverters carry none because equal inverter efficiency is assumed, which real products will not match.