Calculateur de Dimensionnement de Batterie ASI — Formule

UPS Battery Sizing

Proper battery sizing ensures the UPS provides the required runtime at the expected load.

Formula

Capacity (Ah) = (Load / Efficiency) x Runtime (hours) / Battery Voltage / DOD

Where DOD is the maximum depth of discharge (80% for lead-acid to extend life, 90% for lithium).

Sizing Considerations

  • Battery capacity degrades over time (plan for end-of-life capacity)
  • Temperature affects capacity (reduce by 1% per degree C below 25 C)
  • Higher discharge rates reduce effective capacity (Peukert effect for lead-acid)

    • Exemple Résolu

    2000 W load, 30 min runtime, 48 V battery, 90% inverter efficiency, 80% DOD.

    1. Runtime in hours: 30 / 60 = 0.5 hours
    2. Actual draw: 2000 / 0.90 = 2222 W
    3. Capacity: 2222 x 0.5 / 48 / 0.80 = 28.9 Ah
    4. Energy: 2222 x 0.5 / 0.80 / 1000 = 1.39 kWh
    5. Discharge current: 2222 / 48 = 46.3 A