pvperfsolar performance modeling

Reference

API field

Max. efficiency

Peak efficiency; used as a flat efficiency when no curve is given

Unit %

What it is

The peak efficiency of the inverter, in percent. When no efficiency curve is given, the inverter runs at this efficiency above its power threshold. With the straight-line Sandia law (Model tab: Sandia, no voltage terms), the DC input at which the output reaches the AC nameplate is the nameplate divided by this efficiency. With curves present it is read by the straight-line Sandia law and the PVWatts curve, as their nominal efficiency, and by the flat law. An AC-coupled battery with an empty AC conversion efficiency takes the PV inverter's peak efficiency: the highest efficiency of its curves, or this value when it has none. The default is 98 %.

Typical values and how to get it

The OND value; 97 to 99 % for current utility inverters. If not given: 98 %, also when an OND file has no EfficMax.

References

  1. King, Gonzalez, Galbraith & Boyson 2007, Performance Model for Grid-Connected Photovoltaic Inverters, Sandia report SAND2007-5036
  2. NREL SAM Simulation Core (SSC) source code, release 2026.7.3, github.com/NatLabRockies/ssc: shared/lib_sandia.cpp, sandia_inverter_t::acpower(); ssc/cmod_pvwattsv8.cpp, the inverter parameters and the clipping

API

inverter.max_efficiency — sent as a fraction 0–1