power

Calculates optimal solar panel string and MPPT configuration based on panel electrical specs, inverter/charge-controller MPPT limits, and site temperature extremes. Applies temperature coefficients to determine Voc at minimum temperature (cold) and Vmp at maximum temperature (hot), then computes the safe range of panels per string, maximum parallel strings, and total array wattage. Prevents over-voltage damage in winter and under-voltage MPPT dropout in summer. Essential for NEC 690.7 compliant residential and commercial solar design.

post/api/string_sizing

Request

  • Base URL: https://calc.engineer
  • URL: https://calc.engineer/api/string_sizing
  • Auth: none declared

Request body

panel_vocnumber required

Panel open circuit voltage (Voc) at STC in volts

panel_vmpnumber required

Panel maximum power voltage (Vmp) at STC in volts

panel_iscnumber required

Panel short circuit current (Isc) at STC in amps

panel_impnumber required

Panel maximum power current (Imp) at STC in amps

mppt_vmaxnumber required

Maximum MPPT input voltage in volts

mppt_vminnumber required

Minimum MPPT start/operating voltage in volts

mppt_imaxnumber required

Maximum MPPT input current in amps

temp_min_cnumber

Minimum expected site temperature in Celsius, default -10

temp_max_cnumber

Maximum expected cell temperature in Celsius, default 60

temp_coeff_voc_pct_per_cnumber

Voc temperature coefficient in %/C (negative for silicon), default -0.30

Response

Computed result for string_sizing

toolstring required
versionstring required
computed_atstring date-time required

Changes

No recorded changes to this operation across all 1 revision of this API.