Free Battery Capacity Calculator
Calculate the required battery capacity in amp-hours to power a load for a specified duration.
Total Battery Capacity
57.9 Ah
Total Battery Capacity vs Load Power
Battery Capacity Sizing
Battery capacity must account for the load, duration, efficiency losses, and depth-of-discharge limits.
Formula
Required Ah = (P / V) x Hours / Efficiency / DoD
where P is load power in watts, V is battery voltage, Hours is the backup duration, Efficiency accounts for inverter and wiring losses, and DoD is the maximum allowable depth of discharge (to protect battery life).
Example Calculation
500 W load on a 48V battery system for 4 hours, 80% DoD, 90% efficiency.
- 01Load current = 500 / 48 = 10.42 A
- 02Usable capacity = 10.42 x 4 / 0.90 = 46.3 Ah
- 03Total capacity = 46.3 / 0.80 = 57.9 Ah
- 04Battery energy = 57.9 x 48 / 1000 = 2.78 kWh
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