Modules per string

What it is

The number of modules connected in series in one string. The string voltage is this count times the module voltage. The inverter needs the string voltage inside its operating window in cold and in hot weather.

Typical values and how to get it

Size it against the inverter's voltage window at the site's temperature extremes: the cold open-circuit voltage must stay under the inverter maximum and the module's maximum system voltage, and the hot operating voltage above the inverter minimum. About 26 to 28 modules of the current 144-half-cell size on a 1,500 V system, depending on the site's lowest temperature. The System tab shows the voltage check; the API has no endpoint for it. To check a request, take this count times the module's STC voltage (module.v_oc_ref_v or module.v_mp_ref_v), corrected by the relative Voc coefficient (module.beta_voc over module.v_oc_ref_v, or module.mu_p_mp when beta_voc is empty) for each °C away from 25 °C. The tab compares the open-circuit voltage at the lowest ambient temperature of the weather with inverter.v_dc_max_v, the MPP voltage at that temperature with inverter.v_mppt_max_v, and the MPP voltage at a 65 °C cell with inverter.v_mppt_min_v.

API

array.modules_per_string