API field
Series resistance
Series resistance of the one-diode circuit
Unit Ω
What it is
The series resistance of the one-diode circuit model, in ohms. It shapes the curve near the maximum-power point and sets the relative efficiency at low irradiance: a larger value raises it.
Typical values and how to get it
The PAN value, or the library value; PAN files of current crystalline modules carry about 0.1 to 0.4 Ω. Small changes matter: on a 600 W module, 10 mΩ more raises the efficiency at 200 W/m², relative to standard conditions, by about 0.7 % relative. If not given: the module runs on the PVWatts DC model, which does not read it. The one-diode models need it: a request that names one of them without it is refused.
References
- De Soto, Klein & Beckman 2006, Improvement and validation of a model for photovoltaic array performance, Solar Energy 80(1) 78–88
API
module.r_s_ohm