Power Supply Systems and UPS

UPS and battery calculations by task

Separate UPS output capacity, AC input demand and battery duration. These describe different parts of the system and need different inputs.

UPS capacity in kVA and kW — Compare the apparent-power and real-power ratings.

UPS input current — Review the input-power, power-factor and efficiency assumptions.

UPS runtime estimate — Explore the stated battery-energy and load model.

Battery series and parallel configuration — Distinguish DC bus voltage from capacity.

Battery charging current and time — Compare C-rate, charge current and time under the selected model.

VA to amps — Use the voltage of the specific input or output whose current you are evaluating.

Do not use output VA alone to infer the AC supply current during charging. Manufacturer input-current data and runtime curves are needed to check an equipment selection. Browse the remaining calculators below for other system questions.

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