SPECIFICATION SHEET • SI METRIC
CAT: ELECTRICAL-ENERGY

Battery Runtime & Backup Capacity

Estimate battery runtime and required amp-hour capacity from load power, battery voltage, depth of discharge, efficiency, and backup duration.

💡 Engineering Knowledge PrimerBattery runtime depends on stored watt-hours, usable depth of discharge, load power, and conversion losses. This model makes those assumptions visible and reports both the runtime of an existing bank and the capacity required for a declared target duration.
OPERATING LIMITS — Battery runtime and capacity calculation only; verify chemistry, temperature, aging, discharge rate, inverter, protection, cabling, and manufacturer limits before equipment selection.
INPUT DESIGN PARAMETERS (SI)
kW
V
Ah
%
%
h
CALCULATED SPECIFICATION OUTPUT
Nameplate Stored Energy
⚡
19.2 kWh
Usable Delivered Energy13.82 kWh
Estimated Runtime0.55 h
Capacity Required for Target Runtime5787 Ah
Approximate DC Current578.7 A

Related planning checklists

This calculator appears in the following engineering planning checklists:

1. Three-Phase Electrical Power2. Transformer kVA Rating & Load Sizing (IEC 60076)3. Battery Runtime & Backup Capacity

Technical Methodology & Engineering Principles

GOVERNING EQUATION
Stored Energy (kWh) = Voltage × Capacity (Ah) / 1000 Usable Energy = Stored Energy × DoD × Efficiency Runtime (h) = Usable Energy / AC Load (kW) Required Capacity (Ah) = Load (kW) × Target Hours × 1000 / (Voltage × DoD × Efficiency)
Assumptions & Scope

Constant AC load; fixed inverter/system efficiency; no temperature, Peukert, aging, voltage-sag, discharge-rate, or battery-management derating beyond the entered factors.

Operating Range & Boundary

Load, voltage, capacity, and target duration must be positive; depth of discharge and efficiency must be between 0% and 100%.