AC and DC current calculator

Enter the AC output of an inverter and the DC voltage of its string. See the DC input power, the DC and AC currents and the peak of the AC voltage.

Read this first. The defaults are the page's example: the 5,000 W rating is the nominal AC power on the SMA SB5.0 sheets, while the 350 V DC voltage, 97.5% efficiency and unity power factor are invented. Read real limits from the inverter datasheet. Use a dot for decimals; "5,000" is read as five thousand.

Presets:

Inputs

AC output power (W, not kW) Inverter efficiency (%) DC operating voltage (V) AC voltage, rms (V; line to line if three-phase) Phases Power factor (0.5 to 1)

Results

Result	Value
DC input power (AC output ÷ efficiency)	-
Inverter loss	-
DC current (DC power ÷ DC voltage)	-
AC current	-
AC peak voltage (rms × 1.414)	-
AC current as a multiple of DC current	-

Currents here are totals for the whole inverter. Per-input limits, string voltage and breaker sizes are separate checks: use the datasheet and your code.

Method: DC power = AC power ÷ efficiency. DC current = DC power ÷ DC voltage. Single-phase AC current = AC power ÷ (AC voltage × power factor). Three-phase AC current = AC power ÷ (1.732 × line-to-line voltage × power factor). Peak voltage = rms voltage × 1.414 (the line-to-line peak if three-phase).