Battery / UPS Sizing Calculator

Load Parameters

kW
min
%

System Config

Vdc
(Typical: 384V, 480V)
%

Sizing Results

Max DC Current (IDC) - A
Base Energy (Ah) - Ah
Rated Capacity (C10) - Ah
Block Configuration -

*Estimates required C10 capacity. "Rated Capacity" includes aging, temperature, and high-rate discharge factors per IEEE 485 principles.

Technical Notes & Engineering Logic

Variable Definitions

  • IDC (Max Current): Calculated at End-of-Discharge Voltage (Vmin).
  • Vnom: Nominal system voltage (e.g., 384V).
  • Vmin: Battery cut-off voltage (assumed 1.75V/cell).
  • C10: Standard 10-hour capacity rating.

Formulas

  • PDC: Load(kW) / Efficiency
  • IDC: PDC / Vmin (where Vmin ≈ 0.87 × Vnom)
  • Base Ah: IDC × Time(h)
  • Rated Ah: Base Ah × (1+Aging%) / (Ktemp × Krate)

Assumptions

  • Peukert Effect: Krate approximates the loss of capacity at high discharge rates.
  • Aging: IEEE 485 recommends 25% extra capacity for end-of-life assurance.
  • Blocks: Assumes standard 12V monoblocks in series.
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