Solar PV String Sizing
Cold-Voc max series and warm-Vmp min series for an inverter MPPT window.
Example
You enter
- Module Voc (V) 40
- Module Vmp (V) 33
- Voc temp coeff (% per C, magnitude) 0.3
- Record low temp (°C) -10
- Record high temp (°C) 45
- Inverter MPPT min (V) 200
- Inverter MPPT max (V) 480
- Inverter Vdc max (V) 600
You get
- Max series count 13
- Min series count 7
- Cold Voc per module 44.2 V
Details, formula, and sources
Vmax = Voc(STC) × temperature correction at record-low ambient (NEC 690.7); current sizing 125% × Isc per NEC 690.8(A); OCP per NEC 690.9.
NEC 2023 (NFPA 70). Article 690.
Free read-only access at nfpa.org/freeaccess.
Estimate. AHJ and licensed electrician govern. Verify against the NEC edition adopted in your jurisdiction.
Field names used by the API: module_voc_V, module_vmp_V, voc_temp_coeff_pct_per_C, record_low_C, record_high_C, inverter_mppt_min_V, inverter_mppt_max_V, inverter_vdc_max_V, max_series, min_series, cold_voc_V
- Temperature-coefficient default −0.30%/°C unless user suppliesmodule datasheet typical
- Inverter-input window user-supplied from listingUL 1741 listing