Battery Bank Sizing Calculator
Size a battery bank: calculate series/parallel configuration, total batteries, and usable capacity for off-grid and backup systems.
Inputs
kWh/day
days
V
%
Ah
V
Results
Total Batteries
20 batteries
Usable Capacity
6 kWh
Total Energy Required20 kWh
Batteries in Series4 per string
Parallel Strings5 strings
How to Use This Calculator
- Enter your Daily Load in kWh/day — sum all loads multiplied by their daily hours of use.
- Set the Days of Autonomy — the number of days the bank must supply power without recharging (typically 1–3 days for solar backup).
- Enter the Battery Voltage (individual cell/unit): common values are 2V, 6V, 12V, or 48V.
- Set the Depth of Discharge: lead-acid ≈ 50%, LiFePO4 ≈ 80–90%. Deeper discharge shortens battery life.
- Enter the Battery Capacity in Ah (20-hour rate) and your target System Voltage (12, 24, or 48 V DC bus).
- Review Batteries in Series, Parallel Strings, and Total Batteries, then verify Usable Capacity in kWh meets your autonomy requirement.
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