The Battery Bank Sizing Calculator converts a connected load and required runtime into usable energy, then into a bank capacity in kWh and Ah at your system voltage. Depth of discharge and inverter efficiency are applied, so the bank is sized on usable rather than nameplate energy.
Battery Bank Sizing Calculator (Inverter Systems)
Size an off-grid or backup battery bank from load, runtime and autonomy days, applying depth of discharge, inverter efficiency and temperature derating, with a series and parallel layout.
Load
System
Battery module
Results
--
bank capacity
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at system voltage
Notes
About Battery Bank Sizing Calculator (Inverter Systems)
Features
- Load in watts x runtime hours
- 12, 24 or 48 V system voltage
- Flooded, AGM, gel or LiFePO4 depth of discharge
- Inverter efficiency allowance
- Series / parallel configuration suggested
How to Use
- Enter the connected load and the backup hours you need.
- Pick system voltage, battery chemistry and inverter efficiency.
- Read the required capacity in kWh and Ah plus the string layout.
Examples
Example: 600 W for 8 h on a 48 V flooded bank (50% DoD) -> 4.8 kWh of load energy, 10.7 kWh of bank capacity, about 222 Ah, wired 4 in series x 3 parallel.
Benefits
- Sizes on usable energy, so the bank is not chronically over-discharged
- Gives Ah and string layout, not just a kWh figure
Frequently Asked Questions
What does this calculator do?
Size an off-grid or backup battery bank from load, runtime and autonomy days, applying depth of discharge, inverter efficiency and temperature derating, with a series and parallel layout.
Is my data stored?
No. Everything runs in your browser; nothing is uploaded, saved or logged.