API field
AC conversion efficiency
AC coupling: the battery inverter's efficiency; empty = the PV inverter's peak
Unit %
What it is
The efficiency of the battery's inverter. The model applies it once, on the discharge side, in addition to the round-trip efficiency; the charge side has no conversion term of its own. It applies to AC coupling only. An empty value takes the PV inverter's peak efficiency: the highest efficiency of its curves, or its maximum efficiency when it has none.
Typical values and how to get it
Empty takes the PV inverter's peak efficiency: the highest efficiency of its curves, or its maximum efficiency when it has no curves; 97 to 99 % for utility inverters. Enter the battery inverter's datasheet value when the round-trip efficiency covers the cells and their DC side only. When the round-trip efficiency already includes the battery inverter, set this to 100 % so the inverter is not counted twice.
References
- DiOrio, Dobos & Janzou 2015, "Technoeconomic Modeling of Battery Energy Storage in SAM", NREL/TP-6A20-64641
API
storage.ac_conversion_efficiency — sent as a fraction 0–1